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1980 Jeep CJ-7 Inline Six Needs Emissions Compliance


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Well, it turns out none of the collector insurance companies will insure a vehicle that goes off-road. If I wanted a street only Jeep they'd do it, but who'd want a street only jeep?

 

 

Anyway, I don't think there is much if anything missing from this jeep. For those not familiar with my other thread abut hunting and buying, it's a 1980 CJ-7, 258 1 bbl carb, with 3 spd manual and Dana 300.

 

Did they put cats on these in 1980, with the one bbl carb setup? I don't have a cat. There is a sticker under the hood referencing 1976 emissions, and no cat. I do have an evap canister, with 3 ports. I have an EGR valve. What else should be on there? I'm at work right now but I can take as many photos as will help in the morning.

 

Thanks,

 

Jay

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Hi, Jay...The 1980 model is unique in some ways.  The YFA Carter 1-barrel carburetor is a one-year design, and I would suggest treating the OEM carburetor with great care.  If you rebuild the unit, do so without damaging the core parts.  A YFA, in itself, is not rare, they have many applications, including the Jeep 232 engine.  There is only one build code that fits the 1980 Jeep 258 inline six, though.  I can go into details about the tag number and such if you need it.  A rebuild kit is readily available, as this carburetor has many other applications that share the kit.

 

As for the catalytic converter, this came into play on the Jeep CJs in 1975 as we entered the unleaded fuel era.  There are two classes of emissions, however, and you may have either a California certified or strictly Federal certified 1980 model.  If you're fortunate, the emissions decal is still in place under the hood, and that will state what standards the vehicle met when manufactured.  This can also dictate the required emissions equipment.

 

So, look under the hood for the decal, and please share whether this is a California/Federal vehicle or a strictly Federal vehicle, which is possible if the Jeep has been at Arizona since new.  We'll go through the required emission controls at that point.  The decal will state the subset emissions on the vehicle.  A close-up photo of the decal would be useful, a cell phone photo will do.  I can break the information down.

 

Moses

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Ok Moses, here is the only label under the hood. I don't know if it's even original.

 

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Here are some other photos in the engine compartment.

 

air cleaner

 

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carb

 

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evap canister

 

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PCV in

 

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PCV valve

 

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For the time being I'll be going with Plan B, which is "selling" it to my Mom for $1. She lives up in Wickenburg and does not have to do emissions. Then she can add me as a driver on her insurance and I can pay her for that. It will buy me some time to get it squared away.

 

I'd eventually like to do the Howell kit, but I know I'd have to get a 2 bbl intake for that to install to. What years would fit?

 

Thanks

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Very interesting, Jay...The decal is a genuine emissions statement and has the mysterious reference to "1976".  If this decal is on a replaceable body panel, like the hood, it could be from a 1976 model, either that or there is the very doubtful possibility that the emissions "family" is 1976-80.  The decal typically reflects the model year of the vehicle's manufacture.

 

In either case, the decal provides some typical emissions era tuning information plus the notation that the engine requires an EGR (exhaust gas recirculation) system.  (We can discuss EGR if you're unfamiliar.)  According to the decal, there is no reference to Pulse Air or the catalytic converter, normally stated as "CATALYST" on the emissions decal.  For that matter, there is no reference to the catalytic converter whatsoever, and this leads me to believe the decal could represent a Federal (non-California) Jeep CJ built in 1976.  Cats are listed for 1976 models but could be a delete on a Federal (49-State) chassis, as hinted by the emissions decal.  The decal includes rudimentary tuning specifications and hints of 49-State, basic emission requirements, essentially the closed crankcase and an EGR system.

 

Does the fuel filler neck have a restrictor for unleaded fuel?  That would accompany a vehicle manufactured with a catalytic converter requirement.  According to this emissions decal, the vehicle would appear to be "Federal" and does not have references to any California required controls for 1980 or even 1976. 

 

I would check the VIN number, as the underhood emissions look more like 1976 than 1980.  We'll dig deeper once you do a VIN check.  Pre-1981 California versus 49-State is a much different emission controls bundling than the 1981-90 4.2L/258 requirements.  1980 Federal/49-State emissions could be minimal with the 1-barrel 258.

 

Here is a VIN decoder chart for 1975-80 Jeep CJ models.  Compare this with your VIN, and let's confirm chassis year, engine type and carburetor type from this chart.  There are other fine points like the transmission type and gross vehicle weight package:

 

1975-1980 Jeep CJ VIN Breakdown.pdf*

 

*Factory VIN chart courtesy of Morris 4x4 Center...Also provided is this very helpful statement when searching for the ID plate or a frame number: "1971 to 1986 Jeep CJ VIN numbers are usually located in several possible locations. You should find a tin plate on the driver's side firewall near the brake master cylinder. You may also find one on the driver's side dash or the inside body panel by the floor near the parking brake lever. On mid-1980s models it should also appear on the windshield wiper motor cover inside the Jeep. An abbreviated version is usually found on the top of the passenger side frame rail above the rear wheel."

 

We'll break down the required emissions from here.  As for what I see on the engine now, you have a closed crankcase and PCV valve with an open oil fill cap/breather (not legal); an OEM type carburetor with an air filter that appears not to have a provision for the return hose from the oil fill cap/breather; I don't see an air injection pump, though that may not be required, we'll research once you confirm chassis and model information; If there's a thermal air cleaner package, it's not visible; EVAP appears intact, though you need to trace the hose routings and fuel tank/filler tube venting; the EGR is in place, a good thing, as the EGR is passive and can help prevent detonation/ping. 

 

The cat is up for grabs, there's no mention of a requirement on the decal, though you need to verify the vehicle year model from the VIN...Obviously, Wickenburg is an option, but it would be good to know the origins of the chassis, engine and body.  You may, for example, have a VIN mix-up and a 1976 chassis/powertrain.  If so, the vehicle would have a Spicer 20 transfer case and not the Dana 300.  You can confirm the transfer case and transmission type from their casting numbers and tags, or I can clarify from photos.  The rear axle in either case would be an AMC Model 20.  A 1976 Jeep CJ has drum front brakes; 1980 is disc, readily distinguishable.

 

Let's sleuth a bit, Jay.  1976 is the first year of the later boxed frame, a significant improvement over 1972-75 AMC/Jeep CJs.  1980 has pluses, especially disc front brakes, which were introduced in late 1977.  The good news: Whatever we discover, the Jeep should be readily worth $2800, and it has great potential...

 

Let me know what the VIN reveals after following the OEM model chart breakdown.  Crawl around underneath and confirm the components in the geartrain, brakes and transfer case.

 

Moses

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Frankenjeep.

 

It may be this should have a salvage title, although it isn't titled that way. Here is the only plate I can find, the VIN matches the title I have. Notice it's a "Pennsylvania Special Plate", It's located on the passenger side next to the battery tray.

 

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Here is the transfer case:

 

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Here is a shot I tried of the exhaust pipe, from just in front of the new muffler towards the engine. It's old, but maybe not original. No cat.

 

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The VIN is J0D93EC034453 which decodes as 1980, transmission not listed in the chart above, CJ7, GVW 4150, 258 2 BBL !!

 

Front brakes are disc. The frame is boxed.

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Jay...The transfer case from this angle looks like a Dana 300; however, to confirm this, I want you to look at the front flange of the transfer case, where it mates to the transmission.  You should find a round bolt circle flange on the iron transfer case casting and a thin "adapter" from that flange to the transmission.  Here is an illustration of the 1980 Tremec 176-177 transmission case.  The Dana 300 adapter is piece #4 in the pic, a thin and circular plate:

 

Tremec 176-177.pdf

 

The Tremec is tricky, in that its output flange pattern looks similar to the Spicer 20 transfer case front flange pattern (the "reversed Texas" pattern as some call it).  If the transfer case has a circular front mounting flange casting, it is a Dana 300.  Here is a link to Forman's rebuild of a Dana 300 for additional comparison:  http://forums.4wdmechanix.com/topic/260-rebuilding-a-jeep-cj-7-dana-300-transfer-case/.

 

Once you verify the transfer case flange, you should be looking at a 1980 chassis and powertrain at least.  Try to find the frame ID number mentioned as above the rear wheel on the passenger side.  If it's there, see that it matches a portion of your VIN number.  If so, and if you are comfortable about the Dana 300, you have a 1980 chassis, T176-177 transmission type, Dana 300, disc front brakes and so forth.  The decal is either an emissions "family" covering 1976-80, or is simply part of a body panel from another (earlier) 1976 Jeep CJ.  I would go with the body panel idea, I have never seen an OEM decal that did not specifically note the model year of the vehicle.

 

I'm betting on a 1980.  We can dig deeper into the engine's build date, it could be the 1976 variety, we'll see.  This may be a vehicle assembled from more than one CJ, at least with regard to the decal's body panel and maybe the engine.  Don't despair in any case, we'll work through this.  Expect a positive outcome and a way to go with the emissions if necessary.

 

As a footnote, the Howell TBI adapter is for a two-barrel manifold.  If you go that route after establishing this vehicle as a 1980, the Howell 50-State legal kit will require a two-barrel (Carter BBD variety) manifold.  They are plentiful; many have been set aside after Mopar EFI conversions!

 

Moses

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I'll do some more crawling around in the morning, but I wanted to mention that the sticker is in front of the radiator. I also found a couple of other VIN decoders online that showed trans code D as meaning "Automatic, left hand drive, part time 4wd" so I guess it's not the the original transmission (which is cool, wouldn't want an auto in a jeep :) ). Maybe they had to change carbs to swap the trans?

 

Glad to hear that intakes are easy to find, as I think the Howell kit is going to be the best long term solution. I'm not despairing :), I have a running jeep in pretty good shape overall. Just need to iron out the details.

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OK, I crawled under it again today and this is what I found. The transmission appears to be a T-150, the number on the side matches what i found at this site: http://www.jeeptech.com/trans/t150.html

 

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The transfer case appears to be a Dana 20. I think this is the Texas you were describing:

 

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A close up of the rear:

 

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I could not find any numbers stamped on the frame near the passenger rear wheel. So I am going to operate on the theory that it is a 1980, since at one point the State of Pennsylvania said so. I guess when someone switched it from auto to manual they took the easy way and grabbed if not the whole drivetrain (including engine) at least the t-case and trans from an earlier jeep. Perhaps swapping in the radiator support with the 1976 label was an attempt to fool some emissions inspector somewhere.

 

Anyway, I read over the Howell install instructions and it looks like any air injection is no longer required with it to be legal, since they tell you to remove it. I think that if I put a cat and the Howell kit on it will then be legal. Please give me your thoughts on that, maybe I'm missing something.

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Jay...Sounds like the powertrain is 1976, the transfer case is definitely a Model 20, the photo angle confirms.  The back end of a 20 looks too much like a 300 to be definitive.  That's why I asked for this photo angle and emphasized the circular (Dana 300) versus "reversed Texas" (Spicer/Dana 20) pattern. 

 

The Dana 20 is a 2.0:1 ratio low range.  These units can be rebuilt with lower gear sets from Advance Adapters.  Here's a 3.15:1 ratio kit at Summit Racing:  http://www.summitracing.com/nv/parts/add-420315/overview/.  That drives the gearing lower than a stock Dana 300 (2.62:1), and the 20 is very durable.  The Dana 20 was popular on full-size FSJ 4x4 pickups, Ford 4x4s and the classic Bronco...It does have straight-cut gears instead of helically cut, and this makes these units a bit noisier.  With all of the Rhino Lining, you shouldn't hear it, though! 

 

The front disc brakes have to be late '77 or newer.  We can investigate the engine for its year of origin.  The engine's ignition distributor and module would be revealing.  Provide a photo(s).  If the distributor is a Prestolite, it's early electronic.  By 1980, Jeep uses a Motorcraft distributor and module. 

 

We're getting closer to knowing the pieces involved...There is also a telltale frame difference.  The 1976 boxed frame has one less crossmember than later CJs.  We can explore this and pinpoint the frame year...The frame PDF at my recent CJ-7 post could be helpful.  Scroll down that post, you'll find the PDF of a factory frame on the 1981-86 models.  The first version of this frame may go from 1976-79, the years of the Quadratrac transfer case behind the THM400 transmission.  We can confirm that feature.

 

Moses

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I took a look today, and I have a crossmember that looks to be in the same place as No. 4 on the diagram. Just forward of right over the pumpkin.

 

Yesterday I talked to a waiver referee about my plan with the TBI kit. He said that since 1980 required an air pump, I would still have to have one. This contradicts the install instructions from Howell as well as two separate write ups on installing it I read online. One from a guy in California with an 81 CJ-7 with the 258, and an article on JP mags website about an Arizona based J10 with a 304. I sure hope that guy is wrong. What do you think?

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Here's how I see this:  The Howell kit comes with instructions that comply with a California E.O. (exemption order) number.  If the kit instructions eliminate the need for the air pump, you will not need it.  If the kit eliminates Pulse Air, which is the factory 1981-90 approach for the catalytic converter, then the waiver referee will acknowledge and go along with that plan. 

 

My knowledge of the kit has the Air Pulse inlet tube pinched off at the cat.  I suggest welding the crimped end of the tube for a safe seal, a simple bead will do.  The Howell kit requires an O2 sensor, and the later 2-barrel intake manifolds have this provision and an EGR valve. (Make sure your future 2-barrel manifold has these features.)  On the MSD Atomic EFI install, the pinched air tube at the cat got sealed with a weld bead.  This was similar to the Howell by layout and TBI concept:  http://www.4wdmechanix.com/MSD-Atomic-EFI-for-Jeep-4.2L-Inline-Six-3.html

 

Note: Here are details at the Howell site for the kit you would need (1972-80 with a 2-bbl. manifold, which also complies with your '80 VIN decode): http://howellefi.com/tbi-kit-1972-80-cj-4.2l-offroad-emissions-legal.html.  You can request installation and emissions details.

 

When Howell sought a California E.O., the prototype vehicle(s) had to submit to emissions laboratory testing.  In a four-gas analysis, the tailpipe with a TBI conversion is much cleaner than any carbureted Jeep 4.2L I-6 gasoline engine.  This makes the smog equipment deletes more than acceptable.  The air pump and the later Pulse Air system components should be unnecessary with these tailpipe readings.  A cat (without air injection) and EGR will likely be needed.

 

Note: EFI/MPI/TBI engines eliminate air pumps by controlling air/fuel mixtures tightly and cutting off the classic fuel enrichment that accompanies deceleration on a carbureted engine—the phenomenon of "venturi effect". Essentially, the emissions can be largely controlled by the engine management computer.  An EGR system may be necessary, and if the chassis has a cat, it stays, too.  The cat is a passive, downstream method for further cleaning up the emissions.  On carbureted engines, air injection enhances cat performance under a variety of engine conditions.

 

Get the instructions to the Howell kit, I'm sure that Howell will gladly furnish them.  See what stays and goes.  When you're ready, you can enlighten the waiver referee tactfully, he's simply trying to do his job.  In the carbureted version of the 4.2L, the air pump is a mandatory and struggles to keep the emissions in check.

 

Let us know the official 50-State legal Howell package requirements, Jay...They address this question regularly.

 

Moses

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Thanks Moses. I had already read Howell's installation instructions, which is why what he was saying was so confusing to me. Hopefully, by the time I can afford a kit and put it on it will just pass, and there won't be any referees involved.

 

So do you believe I have a 1980 frame, then?

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Frame could certainly be a 1980 if cross members match with the illustrations.  Should not be a '76...This could account for the disc brake front axle, too.  We can even narrow down the front axle components.

 

Is the body ID still in place at the windshield, driver's side?  Any factory decals on the door sill of the tube, driver's side?  Does the tub look like a matching fit for the frame?

 

Did you look at the ignition?  Prestolite or Motorcraft distributor?  I can interpret from photos of the distributor and ignition module.

 

Moses

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I'll upload some pics of my frame with the tub off.  1983 Jeep CJ with stock frame. Unfortunately, I didn't have a way to get a top down view, so these may not be of much use.  My frame has the front cross member right behind the bumper, the transmission skid plate, the cross member right in front of the gas tank, and the rear bumper.

 

 

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Thanks for the great pictures Case. I wasn't able to get back under it today. Picked up an old friend at the airport today. We're going to do some bird hunting over the next week. He's also an A&P certified mechanic so I'm putting him to work on the Frankenjeep too :).

So tomorrow while we're doing the tie rods and putting on the new top I'll compare my frame to yours, although from memory I think it's close. My crossmember might be a few inches farther forward. I'll get some pics of the distributor too, Moses.

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Upland game birds or doves, Jay?  Taking the "new" Jeep CJ-7 hunting? 

 

An A&P friend will give the Jeep a good once-over!  Looking forward to the distributor and ignition module photos.  If the carburetor has a tag and tag number still accessible, please share it, too.  I can nail down the exact year application for the carburetor, and if it's original, the engine year.  The cylinder head casting number is useful, too.

 

Moses

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Sorry Moses, no chance for pics today. We spent all day fighting the tie rods. Had to make two trips into town for tools I didn't have, wound up getting a nut splitter to get the old frozen castle nuts off. Then found the old ends so frozen in 35 years of dried grease, dirt, rust and paint we couldn't get them out even with a  torch to try and melt the old grease etc. So I ordered a new one from Autozone which won't get to their store until Tuesday. The old drag link came right out at least, and I already had a complete replacement for it, since the old one is bent, I guess from a rock. Tomorrow we're going out after quail, I can get to my favorite spot with just my car. So it will probably be Monday before I can take some pictures. Today was a long frustrating experience, hopefully things will get easier :)

 

Which side of the head will the casting number be on?

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You'll walk today off with the quail hunt tomorrow, good idea!   

 

Castings get swapped and exchanged during engine service work...Rather than scrounge and scrape for casting numbers, let's first look at the engine I.D. code.  It's located on the machined pad near the distributor, at the right side of the engine.  Clean the pad and scrape off debris carefully until you find the code number stamped on the pad. 

 

We're interested in the fourth digit.  This should be a letter "A" if an earlier 258 through 1978 (my 1976 hunch).  If the engine is a 1980, expect to find a "C".  These numbers are not guaranteed, as AMC bounced around with various codes representing carburetor type, compression ratio and other combinations, but the code may help isolate the year range for the block assembly.  We'll dig deeper if necessary.

 

Heads built to 1976 differ from '77-'81 heads.  Where is the temperature sender located on your cylinder head?  1980-up has distinct features.  A 1980 temp sender should be at the rear of the cylinder head and on top.  Cylinder head bolt sizes change later, in the mid-'80s, going from 7/16" stud size to 1/2" stud size like the 4.0L.. 

 

The distributor is distinctly different in 1976 if the engine sports that original ignition system.  It would be a problematic Prestolite.  In 1977, Jeep transitioned to a Motorcraft distributor and module, though some engines still had the Prestolite ignition in 1977.  By 1978, Motorcraft was the sole design.  The distributor's drive section is strictly Jeep/AMC, but the cap and rotor will interchange with Ford types.  (To prevent crossfire at the cap, my Jeep Owner's Bible depicts the use of a Ford adapter/spacer and Ford broad cap and big rotor on a Jeep 258 distributor's base housing.)

 

I keep focusing on 1976 versus 1980 because we know there was a 1976 radiator core support body member involved in the construction of this Jeep.  There is also the Dana 20 transfer case and a possible T150 transmission.  (You can pin down the transmission type readily.  Look at the casting numbers on the transmission.)  That has me comparing 1976 versus 1980 parts.  The air cleaner, which has a look of originality, appears mid-'70s, the older style AMC.  The thermal motor moves to the top of the intake snorkel by 1980. 

 

Note: There is also a 232 one-barrel engine, as you may know, and the block stamping ID code could help eliminate the possibility that this engine is a 232.  AMC built the 232 from the mid-'sixties to 1979, and many appeared in the CJ models.  Numerous parts, including cylinder heads, interchange between the 232 and 258.  These two engines share a common bore size.  The 258 has a "stroker" (longer stroke) crankshaft to increase its displacement.

 

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These two photos courtesy of Wikipedia depict a 1975 circa AMC Hornet 232 six-cylinder passenger car engine (at left) with a striking resemblance to your engine photos. Note the distributor, it's a Prestolite.  See the air cleaner, too, it looks very similar to your photo. You can also see how the closed crankcase should look, note the hose from the rear of the steel valve cover to the air cleaner.  I noted earlier that your aftermarket chrome breather cap should be a closed system to an air filter canister inlet, which would form a true "closed crankcase". At right is a 1980 AMC passenger car engine with the air cleaner showing the thermal motor at top and a host of added emissions components, including the air pump that your friendly referee described.  Note the distinct, more "modern" look to the 1980 components, which has me leaning toward 1976 as your Jeep engine's origins. 

 

Looking back through your photos, I see that the carburetor has two accessible numbers:  the carburetor main body casting number and a stamped number below the "Made in U.S.A." at the base of the main body.  Both numbers, especially that stamped number, could be valuable.  If you furnish these numbers, I'll see if they help isolate the carburetor build date and model or engine application... 

 

Moses

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Well it looks like a 1976 258.

 

post-521-0-53468300-1421115440_thumb.jpg

 

Here is the carb number, looks like 71093.

 

post-521-0-56259700-1421115456_thumb.jpg

 

And a few of the distributor.

 

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I was going to tackle the rear main seal today, until I found the ONE oil pan bolt you can't get a wrench on due to the right side engine mount. I'll just have to live with the leak a while longer.

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Sleuthing paid off...The engine code is a 1972-78 AMC/Jeep 258.  Your distributor is an early '70s AMC Delco-Remy application with breaker points, no newer than 1974, as that's the introduction of the Prestolite electronic distributor.  So, either the distributor is a '72-'74 AMC or AMC/Jeep type or the entire engine is '72-'74.

 

For the carburetor, we need the "tag" number if still on the carburetor.  The removable tag number will be something like "YF-6287S" (1972, one variation).  I can nail down the carburetor build and engine application from the tag number if available.  Unfortunately, the stamping and casting numbers do not pinpoint.

 

There is a striking difference between the valve train/rocker arms that takes place between 1972-74.  AMC was slowly transitioning to stamped rocker arms during this period, so many 232/258 inline six engines continue to use a rocker shaft assembly, referred to as the "Type 1" rocker shaft and arms in service guides.  The stamped arms resemble later AMC/Jeep engines.

 

All of this is academic.  If the engine is a 258 from 1972-78, whether rocker shaft or stamped rocker arms, you have a reliable engine design.  The breaker points do require periodic service if you stick with this distributor, and to me that's not earthshattering either.  Should you get tired of the simple chore around changing points, you can update the distributor to either an AMC/Jeep Motorcraft with an external module or an aftermarket, 50-State legal MSD distributor and AL-6 box if you want to go that expense. 

 

There is also the aftermarket conversion kit for converting this breaker point distributor to an electronic unit.  (From my exposure to these conversion kit products, I strongly suggest carrying a set of breaker points and a condenser in your tool box as a backup.)  Frankly, for service in the field, like when you're 20 miles from nowhere on a quail hunt, breaker points are the simplest to troubleshoot.

 

Moses

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Thanks for all the information Moses. I read your article online about ignition upgrades (and I have your book now, too). Have you learned anything new about the 4wd hardware HEI replacement? Is it reliable? Will the emission nazis look at it and fail it?

 

I am reaching a point of wishing I'd just kept on looking. We got the tie rods in yesterday and I think the ball stud seats are so worn that the knuckles should be replaced. Especially the drivers side. We had to put a couple grade 8 washers on the stud there to be able to use the cotter pin and have it go through a castellation. I'm sure this is wrong but not much other choice right now. Changing knuckles looks like a pretty big job.

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This HEI is actually a knockoff of the 250/292 GM inline six distributor, which some have modified to fit a 232/258 engine.  I would get the 4WD Hardware version, as it will fit properly and has the correct drive gear-to-camshaft mesh and oil pump drive relationship.  The price is inexpensive, comparatively, so this is a good option. 

 

My guess is that the referee would likely see the HEI, assume it's an electronic unit alongside a 50-State legal Howell kit and give it a nod.  Better HEI than breaker points in a 1980 registered chassis, right?  The breaker point distributor, if the referee is savvy enough, would be an obvious 1974 or earlier design.  There is also the 50-State legal MSD replacement distributor for AMC inline sixes.  Though spendy, they do have a California E.O. number. 

 

Davis Unified Ignition (DUI) makes a popular HEI distributor as well, they are under $300 at Summit Racing though there is no mention of a California E.O. number.  DUI has a solid reputation and would be a more substantial distributor than the one sold through 4WD Hardware.  In fairness, though, the 4WD Hardware item is really inexpensive if cost is a large concern.

 

As for the steering knuckles, you can likely find a good used pair.  When you get new ball-joints (advised during the changeover), do not use cheap replacement types.  There are some off-shore pieces that really fall short of OE quality.  MOOG, TRW, Mopar or Raybestos would be better brands.  These parts are common, try Rock Auto or Amazon.com on this one...When you swap knuckles out, you can also do a thorough inspection of the front axle shaft joints and wheel hub bearings.  You need to service and recondition the front wheel hubs, wheel bearings and seals, anyway. 

 

You're still ahead of the curve with the $2800 initial purchase price.  Yes, there are challenges, though each one can be overcome...Let us know what you find in the way of knuckles.  David (spdljohn) may have the Dana 30 front axle parts you need, he's replacing his original front axle with a complete Dana 44.

 

Note: The free-wheeling hubs change during the '80s from six-bolt to five bolt flange pattern, the earlier six-bolt like yours (if 1980) are desirable.  Axle ratios can differ, too.  We can discuss these details further...

 

Moses

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Well we took it out today for a desert duck hunt. It was the last day on my last available 3 day tag. It ran fine and got us back home after 200 or so miles of driving on and off road. So now it will have to sit until I get it right.

 

I guess I'll get the distributor first, and start on gathering exhaust parts and an intake manifold. Will any 2 bbl intake form about 1976 to 1980 fit? If I can't find it at one of our many local salvage yards are there any good online sources? I'd like to get all the less expensive pieces and then finish saving up for the Howell kit. It'll take me a few months to get everything together.

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Glad you had some fun with the Jeep, Jay.  A 200 mile on- and off-road excursion can be gratifying. 

 

Over time, you're going to work your way through Frankenjeep and be pleased with your results...Might pay to contact spdljohn and see if his Dana 30 front knuckles are available, that would be a load off your mind.  Check your free wheeling hubs, I'm curious whether they are 5- or 6-bolt flanged to the wheel hubs.

 

As for manifolds, we have this engine pegged as 1972-79 circa, which can be further confirmed by the head casting number.  The gasket sets break out as 1972-80 and 1981-90.  Since the end game is a Howell E.O. legal TBI kit, I would use a 1972-80 2-bbl intake manifold.  1981-86 CJ (1987-90 YJ is similar) has a different part number and features the electric heat riser.  For emissions inspection and the referee, the 1972-80 Howell kit is the pattern that can be considered "original" through 1980 vehicles.   

 

If you plan to keep your current exhaust manifold, the EGR type and plumbing layout will dictate your choice of a replacement intake manifold.  When you search for a 2-BBL intake manifold, make sure you have the EGR valve and plumbing in mind.  EGR will be a part of 1980 model year emissions compliance.  There are two popular EGR manifolds for the year range discussed here:  8126521 (1976-79) and 3236732 (1980). 

 

Your choice of an intake manifold will be based on the EGR system compatibility with your current exhaust manifold casting.  The exhaust manifolds during this period are with or without air pump/air injection.  Review the Howell kit installation to see if an air pump can be removed when installing the TBI kit.  You may need to call Howell for confirmation.  The intake manifold is unaffected by whether the engine has an air pump or not. 

 

The exhaust manifold should be plumbed for air injection if originally from an air pump engine.  Does your exhaust manifold have air injection ports—plugged off if you have no pump in place?  There were some engines without pumps, they use a non-air injection type exhaust manifold.

 

Here is the 1972-80 kit from Howell that will work with a stock 1972-80 2-bbl intake manifold: http://howellefi.com/tbi-kit-1972-80-cj-4.2l-offroad-emissions-legal.html.

 

Moses

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I forgot to mention that I do have 6 bolt hubs. Here are a couple shots of the EGR valve if it will help nail down the manifold year. I didn't take pictures but my exhaust manifold does have air injection ports (plugged), so perhaps is newer than 1974? Not sure when they started doing that. 

 

post-521-0-18377900-1421462444_thumb.jpg

 

The part number is pretty clear on this one:

 

post-521-0-01828700-1421462449_thumb.jpg

 

I have read and re-read the Howell instructions and the CARB EO and they both say air injection is no longer required. When the time comes I will take along all documentation, receipts etc.

 

The exhaust system will need some fabbing. I have what seems to be a pre-cat front pipe, and the new muffler is welded to it, with a short turn down welded to the back of it. No original hangers seem to be there, just one added in at the new muffler. Any idea how long the original front pipe was with a cat? I think I'll need to shorten what I have or just get a replacement made at an exhaust shop.

 

I ordered the distributor from 4wd parts today. Sometime in the last day or two they stopped bundling ignition wires with it and now it's priced at $99.

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Jay...This EGR valve, which looks original like the distributor, is a gem for identifying the emissions package.  So is the air pump exhaust manifold.  Your engine, based on the engine code, Delco-Remy breaker point distributor, EGR valve and the manifolds, is a 1974.  The exhaust manifold should be a part number 8125077 for 1974 with an air pump.  The same manifold can replace a non-air pump manifold by plugging the ports, as they did with your system. 

 

Note: The reason why your front pipe is a non-catalytic converter type: This is a 1974 pre-cat exhaust manifold and pipe.  Do not discuss engine year with the referee, it has no bearing on the exhaust emission performance but could be misinterpreted as an older engine retrofit into a 1980 chassis, which opens another issue...You have an engine that is essentially the same as a 1980 for emissions control purposes and otherwise.  Howell has certified this TBI conversion kit to cover 1972-80 engines.  Enough....

 

If the exhaust manifold casting number is 8125077, I'm banking on the entire engine being a 1974 258.  This is actually not a bad situation overall.  This exhaust manifold starts in the 1966 AMC passenger car engines (199 and 232) and progresses up to 1974, its last year of usage.  Your referee "knows" that your 1980 chassis requires an air pump for the original emissions system; however, as you share, the Howell information should indicate the delete of the pump and its hardware under the "package" installation.  The referee just needs to know that the delete is part of the California E.O. exemption.  So you have the option to either:

 

1) Keep your current exhaust manifold and EGR system and find a two-barrel intake manifold from the 1973-74 era 232/258 with the EGR provision.  I found a 8129342 intake manifold part number; you can confirm whether this is a two-barrel type and not your current 1-barrel intake manifold number.  Be sure it has an EGR provision.  The referee will look for a functioning EGR system, not break it down by model year.  We can discuss how to hook up EGR, that information may also be in the Howell instructions.

 

2) Get a 1980 intake and exhaust manifold under the part numbers 3236732 (intake manifold) with a 3236582 exhaust manifold. If you get the matched 1980 manifolds, be sure to get the EGR valve and plumbing with it

 

Once Howell Engineering assures that you do not need an air pump system for its 50-State legal E.O. installation, you should be okay.  Otherwise, both the 1974 and 1980 AMC and Jeep engines offered air pump systems.  If you must run an air pump (sounds unlikely), make sure you get the one that fits up with the exhaust manifold you choose.  Get the pump brackets, pump, valves, tubing, hoses and hardware.  To broaden the parts sources, you can also pick through AMC passenger car and Jeep J-truck equipment from this era.  You're not stuck with Jeep CJ equipment, which could raise the price of some parts.  Make sure the air pump system works with the manifolds you choose.  To simplify, get all parts from the same engine.

 

Note:  As a point of interest, I researched at eBay and came up with an alleged 1974 Jeep 258 one-barrel manifold set.  Your current manifolds should look just like this setup: http://www.ebay.com/itm/Jeep-AMC-Intake-Exhaust-Manifold-w-Carburetor-Fits-258-6-cyl-engine-/151540842990.  Take a peek and confirm, note the heat riser, EGR and other features.  This is one more way to verify your engine's origins.

 

As for the HEI distributor, the referee will be happier with an HEI than a breaker point and likely will not create an issue here.  Otherwise, he's looking for a 1980 Motorcraft ignition.  I would be very surprised if the distributor type makes any difference to the referee in this case, the key is the Howell kit with an E.O. decal and the instructions indicating the emissions deletes.  The catalytic converter and EVAP being part of the 1980 chassis, expect a requirement there.  A legal cat without air injection or Pulse-Air should suffice here.  Tailpipe readings will be quite clean with the Howell TBI system, and that's the point.

 

One option you have here is to sit down with the referee before the tests.  Bring a copy of the Howell instructions for the 1972-80 E.O./50-State legal kit.  Tell him you're interested in passing the test the first time around.  Confirm what he wants to see.  I would guess:  EGR, a catalytic converter, the Howell system installed as per instructions with the E.O. decal, the intact EVAP system and a non-vented gas cap.  He may want a CTO (coolant temperature switch/sensor, a simple device) for the EGR valve vacuum and possibly the distributor vacuum advance.  We can discuss this last item.

 

Moses 

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Thanks again Moses. When I got home tonight I shone some light around and found some more numbers. On the intake manifold I found 3225202-2 and what looks like a date: 9.3.75

 

On the exhaust manifold I found 3190800, over the letters BV.

 

The left side of the engine block below the manifolds has 3224098. Hopefully those will mean something to you :).

 

As far as manifolds go, I assume any matched set from 75-80 would work? Or if I have 75 set already then am I good with any 75-80 intake?

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Moses, I've been doing some more digging online and I found this document: https://drive.google.com/file/d/0B9wA8jeRfSFjN2tTdllhenFRV0E/view?usp=sharing

 

which decodes engine numbers. It looks like my engine build date is Sept 10, 1975. That matches up very closely with the date on the intake manifold. Am I interpreting all this stuff correctly? It leaves the distributor unexplained but maybe someone had trouble with the Prestolite and put in the old fashioned breaker point system as more reliable. What do you think?

 

If it's a 1975 engine I think it makes finding an intake a little easier.

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Well, this is a 1976 model year engine from your findings, Jay...You did some really good research here, and the emission decal is now making more sense.  New models come out in the fall, the September 10, 1975 engine build date would be consistent with use in a 1976 model vehicle.

 

The breaker point distributor was confusing.  However, the Prestolite distributors are so bad that someone might readily resort to installing an earlier breaker point Delco-Remy unit. 

 

I did some more homework, and the Federal '76 CJ-7 could be a non-catalyst engine/chassis as indicated from the decal.  We know that the distributor is '74 or earlier, we can confirm actual year application from the distributor number once you pull out the unit.  Your speculation about an earlier retrofit distributor is likely correct, as the first Prestolite distributor is the 1975 model year engines.  I can't find a breaker point listing past 1974.

 

So, this intake on eBay should work.  As for condition, ask about what appears as a threaded mount at the right (forward end) of the intake manifold.  Compare that mount with your current setup if you have any attachments at the front of your intake manifold.  This intake should mate with your current (EGR type) exhaust manifold...You'll need to also compare the EGR valves, the later manifold (1978 indicated) may require a later EGR valve, though I doubt it.  This is not a very expensive item, regardless, and quite likely your original EGR valve is tired.

 

As for the non-catalyst 1976 powertrain, the issue would be your 1980 model title.  It would seem easier to install a catalytic converter if you want the 1972-80 Howell TBI 50-State legal kit.  You would register the vehicle as 1980.  Otherwise you need to "prove" to the DMV that the Jeep is a 1976 49-State model with a later front axle, disc brakes and so forth.  If the frame is 1980, that's one more reason to register as a 1980.

 

Moses

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Thanks again for all the help, Moses. I just snagged the intake from ebay. 

 

I think my chances of proving it's a 76 jeep would be pretty slim :). So I'll go ahead with the plan to modernize it. The Howell instructions do call for the CTO and even list a Jeep part number. My research on that turned up the fact that the part number they give apparently doesn't exist. I found a cross reference online for a Borg-Warner part which I found at Autozone. So I have a few key pieces on the way. Once I piece together an exhaust system I can start saving up for the Howell kit.

 

I don't have a fuel return line now, I'll need to figure out what happened to it. I might need a different evap canister too. One step at a time, I guess :)

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This is straightforward around the CTO.  We'll discuss setting up an EGR and distributor vacuum advance when you're ready.  Just ask, the concept is simple in purpose and layout...

 

Glad you bought that manifold, the price was very right, the stock iron manifold will make everyone happy.  Before installing the manifold, clean (ideally, bead blast and then clean) thoroughly.  Check the mating surfaces with a straight edge for relative flatness.  The thicker gaskets compensate some here, you're looking for major warp.

 

Good job, Jay!

 

Moses

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OK, I guess this will be a "build" thread from now until I get it to pass emissions. I'll update it as I get and install pieces.

 

Today I put the 4wd hardware HEI distributor in. And it even starts!

 

But I caused another problem doing it. In order to get a wrench on the crank bolt and get it to TDC on #1, and be able to see the timing marks at the same time, I figured I'd take the fan off. There is no clutch on it, just 4 bolts. I didn't realize it at the time but those 4 bolts were all that were holding the pulley on too. So when I began turning the engine over I could see the belts trying to remove the pulley. I took the belts off, got it set and put the distributor in. Then, using the five hands I don't have I got the bolts back in through the fan and pulley to the water pump. The pulley was spaced with 5 washers and I don't think I lost any. I put the belts back on and finished up the ignition, changing the plugs, new wires, hooking up the tach and batt wires etc.

 

Then I started it. It runs rough of course but it runs so I guess I got the rough timing right. My Harbor freight timing light isn't flashing though so I can't check the timing. The problem is the pulley and fan are way crooked and I'm afraid if I run it any more I'll destroy the water pump, if I haven't already. Any ideas on what happened with it or what I should do? I haven't had the energy to take it all back off yet today.

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Jay, the orientation of the fan pulley, the fan and the hardware begins with the pulley fitting directly against the water pump hub flange—no "spacer washers".  There may be an aluminum fan spacer between the pulley and fan since there's no clutch fan unit.  You may have a direct drive aluminum spacer that rides against the pulley (inside of spacer) and doubles as a mount for the fan (outside of spacer). 

 

Whether you have a direct drive spacer or not, the fan should always fit flush against a machined aluminum spacer or the fan clutch.  Rarely does a fan fit against the pulley unless there is a deep cone to the pulley.  (Otherwise the fan would chew up the belt.)  Always make sure the fan clears the belt and is in proper fore-aft alignment.

 

Fasteners should be four bolts with lock washers and flat washers in some installations.  "Factory" is usually a set of graded bolts with lock washers built onto the bolts.  Your setup from the factory included a fan clutch.  It has likely been replaced with an aluminum spacer as I'm describing, perhaps the fan is aftermarket (Flex-a-Lite or other product). 

 

Take a couple photos of the parts orientation and post here.  I'll comment further...

 

Moses

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The "spacers" are behind the pulley. There is a real spacer between the pulley and fan.

 

Here is the fan and pulley:

 

post-521-0-14397400-1422146689_thumb.jpg

 

I can come up with a theory about anything and here is what I think went on. They guy I bought it from put on a new water pump, and I bet he bought one for a 1980. Both Rockauto and Autozone show different parts for 1976 and 1980. They look a lot alike, but my guess is the pump flange sits farther out on the 1976 pump. So he put the washers in there to get the belt grooves to line up, as well as keep the pulley from grinding against the block. So since I didn't get them all equally tight (even in the hand tightening phase) it went on crooked. I was able by backing them all out and gradually tightening them to get it about like it was before. Good enough that I could run it a bit.

 

I think my Chinese timing light has a bad inductive pickup, I got it to flash a few times but that was it. I moved the distributor enough to smooth out the idle a bit and called it a day. Here are a couple of the snazzy new distributor:

 

post-521-0-33471800-1422146707_thumb.jpg

 

post-521-0-35335800-1422146730_thumb.jpg

 

So in addition to a timing light that works I guess I need to get another water pump.

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Did you compare the stick-out lengths of the two water pump flanges, 1976 versus '80?  The theory sounds very plausible, since '80 does have the fan clutch and may have required a shallower water pump and less cone/dish to the pulley.  The current pulley looks like a deeper belt offset.  You need to remedy this...It's not safe to have the fan pulley spaced out by washers.  There's also a high likelihood that the washers have pushed the pulley to the edge of the water pump pulley locating stub.  This would account for the severe fan and/or pulley wobble.

 

Until you get that new timing light, there are two effective ways to set timing without a light, each is a "field emergency" approach: 1) use a vacuum gauge and advance the timing to the highest vacuum reading at an idle, then back timing off as necessary if the engine detonates/pings under load, or 2) advance the timing to the highest rpm reading, using just a tachometer, then drop the timing back 75-150 rpm to eliminate ping or detonation (adjust as needed to eliminate ping/detonation). 

 

These are each temporary settings, you need to tune the engine with a timing light, making sure the vacuum advance hose is disconnected and taped as you set the base timing.  This vacuum source is carburetor ported vacuum, not manifold vacuum.

 

Did you get a chart with the spark timing "curve" (vacuum and centrifugal/mechanical spark timing) for this distributor?  Otherwise, we'll have to assume the curve is close to stock, maybe a bit brisker.  Set the base timing close to the factory recommendation or no more than 8 degrees BTDC at an idle with the vacuum advance hose disconnected.  2 to 6 degrees BTDC is a typical 258 setting at an idle with the vacuum advance hose disconnected...Always reconnect the vacuum advance hose after setting the timing and check for ping/detonation under load.

 

Moses

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Hi Moses,

 

As far as I can tell by looking at photos on the internet, the 76 pump's shaft does appear to stick out more. I'll be ordering a new Gates brand pump from Rockauto this week, less than $20. The current pulley is quite deep. I'll also get a real timing light this week, too.

 

I believe I do have a timing curve chart, I do remember at least seeing instructions on how to adjust the vacuum advance if necessary.

 

On Friday I also received the 2 bbl intake. I haven't had a chance to start cleaning it up yet, but I did notice the build date on it is 12/10/76, so I think it ought to go right on. Do you happen to know off hand what size nuts I need to get the old carburetor studs out?

 

One other thing that I've been worrying over, with the new HEI setup, do I still have to be careful of having the key on, engine off like with the old setup? I'm assuming so. Is disconnecting the Batt lead enough?

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With your HEI, if patterned after a GM HEI from 1975 to the end of the conventional distributor era, you could have the engine fire while you're turning the engine over by hand, if that's the concern.  If the primary (smaller gauge) wire lead to the distributor is the same lead that formerly served as the primary signal from the coil, it would be KEY ON hot and KEY OFF dead.  (Check the lead with your voltmeter in each key position.)  KEY ON could trigger a spark if the distributor shaft moves.  The HEI pick up and pole piece use a magnetic pulse signal and module instead of distributor cam lobes and breaker points with a condenser...I would not test whether there is spark with your hands anywhere near the crankshaft, fan or pulleys! 

 

Note:  If you're asking whether you can set spark timing like with breaker points (by moving the distributor housing by hand to fire a spark plug), that might not be possible with the HEI.  The magnetic pulse would be erratic with the engine not running.

 

Glad you have a water pump coming.  The current arrangement is dangerous.  When I was in high school, a classmate bought a '58 Ford Ranchero with the 332 V-8.  He was revving the engine with the vehicle stationary.  The direct drive fan and water pump impeller pulled forward like a propeller and snapped the shaft loose with the fan.  (This scenario was not that unusual before the days of fan clutches, though modern clutches come apart, too.  Vehicle stationary, the fan wants to pull forward.)  The fan flew upward into the hood.  (Fortunately, this '58 Ford hood hinges at the front and lays rearward above the engine.)  Luckily, he was away from the fan and did not get injured.  The damage was to the hood and radiator.  Moral:  Do not get over the top of your fan with the current pulley and washers arrangement and the engine running.  For that matter, do not get in line with the fan with the engine running...This is the reason for steel safety shrouds.

 

The carburetor nut wrench size should be 1/2" (12mm if nuts are U.S. thread with metric outer hex, not unusual as OE or aftermarket parts).  The manifold/carburetor stud size is 5/16" with 5/16"-24 SAE Fine on the top side (nuts you need).  The manifold casting end of the studs should be 5/16"-18 thread or U.S.S. course.  Sounds like you're double nutting the studs to remove them without scarring.  Good idea.  I would soak the manifold ends of the studs with penetrant first.

 

Moses

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Hi Moses,

 

I remember seeing something on the web about burning up ignition coils by having the key on, engine off for a long period of time (how long I don't know) like when probing for key on hot circuits or other testing. Maybe that problem was for the later 1981 and on CJs.

 

I should be able to tell with a tape measure if the 76 water pump will fix the issue, if not I'll have to find a shallower pulley.

 

Thanks for the nut info, yes I was planning on PB blaster and double nuts. Sounds like a sundae :)

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Jay...The HEI module is better than the Ford/Motorcraft module in this regard.  Your HEI, if using GM type components, has a robust design with the coil-in-cap.  Of course, leaving the key on for long periods would not be advised in any case, though I've seen GM systems left on without damage to the module or coil.  The module does heat up in running mode, but KEY ON for a reasonable period without the engine cranking should not burn up the module.

 

I'm curious how 4WD Hardware can sell this complete distributor for $99.  Does the unit seem well built?  Is there any issue with parts quality?  We'll assume the assembly is made offshore, though so are most U.S. replacement parts these days, including many of GM's own Delco-Remy parts.

 

Looking forward to the update on the water pump nose length and pulley alignment...

 

Moses

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Thanks Moses. I'll eventually need to troubleshoot my fuel and temp gauges, so if it's going to take a while I'll play it safe and disconnect the batt lead to the distributor.

 

Rockauto came through for me again, not only cheap but fast. Ordered a box of parts on Tuesday and got it this morning just about 48 hours later. The 76 water pump sticks out at least 1/2" farther to the face of the flange so it should solve the pulley issue. I also got a new EGR valve for later, a new PCV valve, a new temp sender (probably nothing wrong with the old one but what the heck?) and a new exhaust flange gasket for when I get to messing with the exhaust.

 

As fas as the distributor goes, I have no idea how they are doing it for $99. I haven't handled many, the last one I changed was about 15 years ago, but it looks well made to me. Machined from a billet of aluminum. The vacuum advance parts are stamped steel. The hall sensor/module is encased in plastic so I can't see in it. I wish I'd taken some pictures of it before I put it in.

 

I won't be able to get to the water pump until Saturday. I'll post a follow up then.

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Water pump is in and everything now lines up correctly. My new timing light arrived yesterday so I got the timing set to 6 deg BTDC, After I hooked the vacuum back up I revved it to 2150 (per the timing light) and it showed 32 degrees of advance, with the mark back on 6 BTDC. Does that sound about right?

 

I took it for a short unlicensed :) road test and although it's only seat of the pants, it does feel a bit peppier with the new distributor. Couldn't hear or feel any pinging. I have a tach installed now too, so I saw approx 2400 rpm at 65 mph (per GPS, I have the wrong speedo gear). So I believe I have 3.55 gears, which was a pretty common ratio, right? Looking at Quadratec's tire/gear ratio chart I'd line up closer to 3.42, but I don't know if they ever sold any like that. My timing light also was reading about 75 rpm higher at idle than the tach in the cab. Since the timing light cost more I'm assuming it's more accurate :) . If the tach is off even more at higher rpm I could even have 3.73. 

 

I also put in my new temp sender and the gauge moves now, just barely into the normal range.

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Jay...Since you say, "...with the mark back on 6 degrees BTDC", I believe you bought a timing light with built-in advance adjustment?  If so, is your total advance 32 + 6 degrees BTDC?  If the total was 32, the dial back would be 26 BTDC.  What we want here is total crankshaft advance degrees for the centrifugal/mechanical advance (vacuum hose disconnected to the advance unit).  You can then check total crankshaft vacuum advance degrees at an idle by simply using a hand vacuum pump attached to the distributor vacuum canister.  Stay away from the fan during all of this work!

 

By 2150 rpm (crankshaft, presumably), the vacuum advance should be waning or nil.  This is ported vacuum, highest at throttle tip-in and dropping to zero when the throttle opens and the throttle plate creates little to no vacuum at the port below the throttle plate.  (See my exchange with Forman on his tuning of the 4.2L/258 and a Weber carburetor.)

 

I'll share some time-honored, best performance "curve" specs and the base timing for a 258.  This is from my library and reflects actual truck needs and maximum efficiency, presumably without ping.  (Ping will require backing down on total centrifugal advance degrees or just the vacuum advance, which is adjustable in your case.)  I like to see 28 crankshaft degrees or so of distributor centrifugal advance by 3200-3600 crankshaft rpm, depending upon the vehicle weight, gearing and usage

 

Note: As a point of interest and comparison, the 1971 Jeep 258 J-truck engines (pre-severe smog era tuning) call for a maximum 28 crankshaft degrees of centrifugal/mechanical advance by 4,400 crankshaft rpm—the advance starts moving just off-idle and reaches 18 crankshaft degrees advance by 1900 crankshaft rpm, a steady and wide advance curve.  Add vacuum advance and base timing degrees to this.

 

Many aftermarket "performance" distributors bring total advance by 2000 crankshaft rpm, and that's okay as long as the engine does not ping.  (If your 2150 is crankshaft rpm, that's not unusual.)  Base timing should be 2-6 degrees BTDC dependent upon ping.  30-34 degrees of total crankshaft advance (centrifugal advance plus the base timing) is plenty at cruise speed.

 

Vacuum advance is a wild card, as the base timing plus vacuum advance will determine the engine's tip-in throttle response and the degree of ping risk.  Start by setting the centrifugal advance and making sure your vacuum source is "ported" and not manifold for the vacuum advance.  You can test drive the Jeep for cruise speed and higher speed acceleration response.  Check the response under load or when "lugging" somewhat.  If okay, then concentrate on the vacuum advance.

 

For a baseline on the vacuum advance, get your idle as slow as reasonable.  Use your vacuum pump and apply 3-7 in/hg vacuum.  This should have the vacuum advance just beginning to move and registering as crankshaft advance with a slight rpm increase.  As you pull more hand vacuum, by 17 in/hg, there should be full vacuum advance with a crankshaft degree reading of 20-22 degrees (beyond the base spark timing BTDC).  This gets slightly confusing, as the increase in vacuum advance will naturally cause the engine's rpm to increase, and the centrifugal advance begins to move as the rpm climbs.  Try to keep the idle down for an accurate read on the vacuum advance.

 

Years ago, we removed the distributor from the engine and did the distributor testing and advance curves (both centrifugal/mechanical and vacuum advance) in a distributor testing machine.  The specs did not involve a running engine nor base timing.  (The degrees of advance were always listed as distributor degrees and distributor shaft rpm, which is 1/2 the speed and degrees as crankshaft speed and degrees.)  Once the distributor was completely dialed on the distributor test machine, the distributor was reinstalled in the engine.  The base timing was set, and the tune-up was complete. 

 

In the breaker point era, it was often much easier to do the points and condenser in a distributor machine—especially on engines like the 1932-48 Ford flathead V-8 with the crab tree distributor mounted at the front of the camshaft!  The biggest breakthrough for in-engine distributor work was the GM window cap distributor with "pre-adjusted to start" breaker points, introduced in the 1956 Cadillac V-8s.  From 1957-74, this was GM's V-8 and V-6 (not inline six) tuning gift from Delco-Remy.  The window cap provided the easiest to tune breaker point distributor in the automotive industry.  Jeep took advantage on the Vigilante (AMC 327) and Dauntless (Buick 350) V-8s, AMC/Jeep 304, 360 and 401 V-8s, and some of the Buick/Dauntless 225 V-6 engines (those 225s fortunate enough to not have the Prestolite distributor).

 

Moses

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Yes, it was 32 + 6 if I'm following you correctly. The display read 32 and the timing mark was at 6. So it sounds like I should back it off a little, although I'll recheck it with the vacuum still disconnected and verify it is ported vacuum. I'm pretty sure the vacuum line goes to the carburetor.

 

The timing light is an Innova 3658, I assume it's calculating RPM from the ignition pulses.

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I just went out and checked where the vacuum advance hose goes. It connects to a port at the base of the carb, right above the manifold, so am I correct in assuming this is manifold vacuum? If so that's probably where my extra advance is coming from. I could tee it into the EGR which comes from a port at the top of the carb. Then I could use the free port to plumb in the dash mounted vacuum gauge I ordered. I'm not going to get too worried about it, since this will all get straightened out with the TBI kit and the new 5 port CTO.

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Jay...Simple test of the vacuum:  1) if manifold vacuum, there will be a strong pull with the throttle closed (warm idling), reading high on your vacuum gauge, 18 in/hg or better, and 2) if hooked to ported vacuum, you will have barely any vacuum with the throttle closed and a rapid rise in vacuum as you open the throttle slightly from an idle.  Ported vacuum is strong to 1/8-1/4 throttle (depending upon the carburetor design) then tapers down...

 

This is also easy to test with your finger on the end of the disconnected vacuum advance hose.  Same test, you're the gauge...

 

38 degrees total advance would be too much for your stock 258.  You want no more than 6 degrees BTDC base timing at warm idle with the vacuum advance hose disconnected and taped off.  At that point, with no vacuum connected, the total advance (centrifugal/mechanical) at full advance engine rpm should be between 30 and 34 degrees.  (This is combined base timing plus the centrifugal advance at the full advance rpm.)  It's your choice on the 30-34 degrees total, ping is usually the determinant.  32-34 should be readily achievable.

 

Sounds like a quality built-in advance timing light, and yes, the #1 spark lead pulse is a simple place to pick up an rpm pulse.  The light doubles the pulse reading for actual crankshaft rpm.

 

Moses

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I played around with it a bit this morning after my new hand vacuum pump arrived. I used to have one but it disappeared in one move or another over the years. 

 

The distributor is hooked to ported vacuum, 0 at idle and it begins climbing as soon as I open the throttle. At around 2400 rpm it's at 22" Hg. The timing at that point with the vacuum advance disconnected is a total of 22 degrees. Here is what he distributor instructions say about the mechanical advance curve:

 

Most engines with the HEI distributor typically run the best when the base or initial timing is set at 6 to 10 degrees before TDC. The HEI distributor has a mechanical advance curve that begins at 1200 RPM and is all in by 3600 RPM with 20 degrees of advance,   

 

And here is the paragraph on the vacuum advance adjustment:

 

 The new HEI distributor is also equipped with an adjustable vacuum advance canister.  You can adjust how much additional vacuum timing advance can be delivered under light engine load during high intake vacuum conditions such as during highway cruise, to improve the economy of the engine.  The unit is adjusted by removing the vacuum line to the canister nipple and inserting a 2.5mm Allen wrench into the end of the canister nipple and turning the internal hex set screw. Turning it counter clock wise reduces the amount of advance, while turning it clock wise increases the amount of advance.  The vacuum advance canister is set at the factory approximately in the middle of the adjustment range.  With five full turns of adjustment in either direction.  Turning the adjustment all the way counter clockwise until it stops reduces the amount of vacuum advance to about 2 degree at a vacuum reading of 10 inches of Hg.  Turning the adjustment all the way clockwise until it stops increases the amount of vacuum advance to about 18 degrees at a vacuum reading of 10 inches of Hg.

 

So I'll need to find my metric Allen wrenches or get another 2.5mm and back that off until my total advance is 32-34 instead of 38. Of course it will probably all change with the TBI installed :).

 

BTW, how hard is it to change out the speedometer driven gear on these things. I'm sure the TBI computer will be happier if it's speed sensor is telling it the truth.

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I like your strategy, Jay!  The total of 32-34 degrees at real world rpm and cruise makes the best sense.  Ported vacuum of 22 in/hg at 2400 rpm seems high, but this is with no load on the engine.  The throttle valve setting is still relatively low.

 

Very easy to change the driven speedo gear on a Dana 20.  Simply loosen the speedometer cable at the transfer case and remove the cable housing and driven gear.  Replace with the correct gear and reinstall the speedo cable.  The gear that's not easy to change would be the drive gear on the output shaft of the transfer case.

 

Moses

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  • 8 months later...

Howdy,

 

Sorry it's been so long since I've updated this, but there really hasn't been anything to add. I'm not any closer to having the scratch needed to buy the Howell TBI kit. I've decided for the interim I will get collector's insurance and not take it off road. If I just use it for hunting everywhere I go there is at least a dirt road. A road is a road, right? :)

 

I have got a few things done to it lately. I finished installing the Tigertop which I set aside back when I was trying to do it in cold weather. Much easier when it's warm out. Also put in the lockable center console I bought back when I got the jeep, so I can lock stuff up and I have cup holders too! I put in 2 new VDO gauges for voltage and oil pressure, and I have a matching vacuum gauge to add later. I'll install it on the stainless instrument panel cover which I put on to cover up the empty radio hole.

 

I do still intend to eventually do the TBI conversion, possible along with an engine replacement at the same time. I'd also like to swap in a Ford T-18 to get some crawling capability.

 

Here are a few updated pictures:

 

post-521-0-03942600-1445826687_thumb.jpg post-521-0-00939900-1445826688_thumb.jpg post-521-0-54485200-1445826689_thumb.jpg post-521-0-84707800-1445826691_thumb.jpg

 

 

And here is how I had to jury rig the door strikers, since my door wells (if that's the right word) don't seem to be the dimension that Bestop expects. These are upside down and on the opposite side (I think) of where they should be, just so the latch will actually contact them.

 

 

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Hi, AZ.Jay!  It has been a while, you've made some progress on the Jeep.  Sounds like the fall may be providing some bird hunting?  The latch is "interesting", if it's secure, all the better!

Keep us posted and enjoy the Jeep, this is the season...The T-18 is a great addition, night and day gear reduction change!  You want the traditional Ford truck version with an Advance Adapters kit.  The AMC/Jeep version of the T-18 has a much taller 1st gear ratio.

Moses

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I got quite a bit done today. First I dropped the tank and put in a new sending unit. I was dreading this job, since I had never dealt with a fuel tank before, but it wasn't bad at all. I like the design they used on the CJ. Only rough spot was detaching and reattaching the filler vent hose. I put 5 gallons of clean fuel in after, but my gauge still shows E. Not sure if it's just way out of cal, or the circuit still has a problem. Hopefully I can legally drive it to the gas station next week and find out :).

I also reinstalled the spare tire carrier, with a reinforcing plate for the top hinge, and I put on new tailgate cables. The next big job will be the still leaking rear main seal.

Here's the old fuel sender, with that rotten piece of fuel hose on the pickup I'm surprised I was getting any fuel to the carb!

 

20151031_204728034_iOS.thumb.jpg.b9efc5c

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  • 1 month later...

Well I'm pretty much back to square one. Now the excuse the collector companies give me is that it's not nice enough for them to bother with.

 

So with some overtime I might be able to get the kit next month, or February.

 

I started putting on the exhaust I bought a few months ago. I need to go get some more adapters and clamps. I can tell that in order to get it all on I'll need to remove teh transmission shield.mount. Any pitfalls to look for there? The transmission won't fall out, right? :) I'm going to have to cut the pipe far enough forward do that the adapter that will come out of the cat will fit in there. The cat itself should be farther back than the transmission shield so I don't think I'll have any interference problems.

 

Jay

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AZ.Jay...The skid plate doubles as the transmission/transfer case mount.  (This is the rear engine and transmission support/mount.)  Yes, you'll need to safely support the transfer case when removing the skid plate.  Look at the top of the skid plate, you'll see the transmission/transfer case mount attached.  To separate the skid plate, you'll need to loosen the transmission mount from the plate.  Be sure the transfer case and transmission have support before removing the skid plate.

Note:  Be careful with the skid plate-to-frame bolts.  The frame nuts are notorious for spinning in the frame.  We can discuss this if a bolt is frozen or seizing.  Use Liquid Wrench on bolt/nut threads before attempting to loosen.

As for positioning the cat, keep in mind that it must fit in a position similar to the OEM cat.  These devices can set brush on fire, keep that in mind, too.  Use a stock vehicle as a pattern for installing the cat and other exhaust parts.  I like the tailpipe to exit at the rear of the Jeep (stock location) to reduce risk of exhaust fumes entering the cab/tub area.

Moses

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AZ.Jay...The skid plate doubles as the transmission/transfer case mount.  (This is the rear engine and transmission support/mount.)  Yes, you'll need to safely support the transfer case when removing the skid plate.  Look at the top of the skid plate, you'll see the transmission/transfer case mount attached.  To separate the skid plate, you'll need to loosen the transmission mount from the plate.  Be sure the transfer case and transmission have support before removing the skid plate.

Note:  Be careful with the skid plate-to-frame bolts.  The frame nuts are notorious for spinning in the frame.  We can discuss this if a bolt is frozen or seizing.  Use Liquid Wrench on bolt/nut threads before attempting to loosen.

As for positioning the cat, keep in mind that it must fit in a position similar to the OEM cat.  These devices can set brush on fire, keep that in mind, too.  Use a stock vehicle as a pattern for installing the cat and other exhaust parts.  I like the tailpipe to exit at the rear of the Jeep (stock location) to reduce risk of exhaust fumes entering the cab/tub area.

Moses

Hi Moses,

I crawled around under it some more today. I have the new muffler and tailpipe more or less hanging where they'll be. What I have is a Magnaflow generic cat, and  Heartthrob cat-back exhaust, including a tailpipe that exits to the rear.

I looked at my 1980 shop manual and it looks like the original cat was connected to the muffler inlet, which is where I intend to put it with this install. Keep in mind there was never a cat installed on my 1976 drivetrain/exhaust so I have to cut the pipe to fit the cat and the appropriate adapter in. Unfortunately that cut (and the clamp for the adapter) need to be above the transmission mount/skid plate. So I will have to remove it. I assume a jack placed under the front of the trans raised until it takes the strain is sufficient support? I think the frame bolts will be OK, as the PO put in a trans drop kit along with the suspension lift he installed. There are approx 2 inch spacer pucks and new bolts all around.

As for the cat, it has a heat shield on one side, I am thinking I should point it down to prevent brush fires. The cat should be 5 or 6 inches below the floor pan.

 

Thanks,

Jay

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AZ.Jay...You can support the rear engine/transmission/transfer case as a unit from the base of the bell housing if accessible.  A block of wood will protect the aluminum while jacking.  Make sure your jack is stable, a jack stand and additional block of wood can be at least a backup beneath the rear section of the engine oil pan.  Don't place weight on the oil pan, it's only tin and you don't want to compress the oil pan or pan gasket.  

The engine has side mounts, so this setup should remain stable, you're basically just balancing the powertrain for dropping the skid plate.  A floor jack would be best, rated 1.5-ton at least.  A stout scissors jack would be the bare minimum.  A bottle jack is too unstable for this kind of juggling...

Moses

 

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