New to Jeeps and what do you think?

[jordan89oak]

Hello everybody,

My name is Jordan, and I am new to the Jeep world. Although I am new to Jeeps, I have been wrenching on old and new muscle cars. I purchased my first Jeep, an '82 CJ7, a few weeks ago. I am hoping to be able to do a little off-roading and enjoy the Jeep with the family. The engine starts and everything, but I didn't drive it home and had it towed.

Unfortunately, I performed a compression test and the results were not good at all. Two cylinders came back with low compression, and one was dead. I performed a wet test on the dead cylinder and the needle jumped right up. I stopped there and just gave into the fact that the rings are bad. I was planning a trip to Yosemite for my wife's birthday in November in the Jeep, but I am not sure it will happen.

I have been thinking about rebuilding the 4.2, or going down to my local Pick&Pull and pull a 4.0 out of a Cherokee and possibly just rebuild that.

What would you guys suggest is the quickest and best solution overall?

[Moses Ludel]

Hi, Jordan...Looks like a good and highly original find.  '80-'86 CJs with the Dana 300 transfer case are a good place to start.  If you take the time to do a cylinder leak down test, you can pinpoint the cylinder pressure loss.  A leak down test on a static engine with each piston at TDC on its compression stroke is far more reliable than a cranking compression test.  There's much discussion at these forums regarding a leak down test.  Try "leak down" or "leakdown" in the search box.

For a rebuild, I would keep the 4.2L crankshaft and find the 4.0L you describe.  A 4.6L stroker would be a solid upgrade.  Again, we have covered the 4.6L stroker buildup both here and at the magazine site.  You can get buildup, tuning and other insights with a search box entry of "4.6L" at either these forums or the magazine site.  

A significant issue:  The 4.0L was not available with a carburetor/intake.  A 4.0L conversion or 4.6L build usually involves converting to EFI with either a 4.0L stock system (complete with PCM and at least the engine wiring harness) or an aftermarket Mopar EFI Conversion Kit, which is now very expensive.  The popular engine choices complete with EFI system would be 1991-99 with a distributor.  Mopar factory EFI and aftermarket conversion kits came in two variations:  1) patterned after the 1991-95 YJ Wrangler/Cherokee 64-way/pin PCM with two rail EFI/MPI and 2) the 1997-99 4.0L (single rail MPI/EFI).  

In my view, it comes down to whether you're ready to make the leap to EFI.  The least costly conversion is a complete 1991-95 4.0L engine with its EFI included, factory wiring harness and the matching 64-way PCM.  A high pressure fuel pump (inline) would replace the stock mechanical pump on the 4.2L engine.  You would need to sit down with a wiring schematic to make up a wiring system similar to what comes with the Mopar EFI Conversion Kit.  That conversion kit is still available from HESCO, currently a mix of 1991-99 MPI/EFI components. 

I did the EFI/MPI conversion on a 4.2L inline six-cylinder engine in my Jeep® CJ Rebuilder's Manual:  1972-86 (Bentley Publishers).  This book is available from Advance Adapters and at Amazon.com; it would be valuable for working on your 1982 CJ-7...At the time I wrote and illustrated the book, the Mopar EFI Conversion Kit was still under $2000 ($1400-$1600 in its original, mid-nineties kit form).  The cost has gone up considerably, and today, I would probably do a recycled 4.0L engine with all of its EFI related components included from the same donor vehicle. 

A 4.2L crankshaft and rebuilt 302/5.0L Ford V-8 injectors would be smart and add little cost to the engine build.  The kitchen table mapping of the wiring overlap with the CJ chassis would save a lot.  It does not take many wire connections to strip out and mate a 4.0L EFI engine wiring harness to an eighties CJ chassis.

Of course, to make the trip to Yosemite next month would more likely involve an in-chassis new set of rings, honing/glaze-breaking and a valve job on the 4.2L engine.  That would only work, however, if the cylinder taper is minimal and pistons can be reused or replaced at the same bore size.  The crankshaft needs to have round journals for rolling new rod and main bearings into the engine...Other approaches like a 4.0L conversion demand time and sorting out parts.

Another consideration is a GM LS (iron block version) or an older 350 TBI V-8 engine conversion.  If done emissions legal, the V-8 would likely get better mileage than a 4.0L or 4.6L in your chassis.  (Realistically, the worst mileage is the emissions 4.2L with a BBD carburetor.)  You have a muscle car background and might prefer the V-8 conversion in the long run.  See Advance Adapters' website for ideas and costs.

Moses  

[jordan89oak]

Moses, 

Thank you so much for your feedback. My local Pick-n-Pull just got as '04 Grand Cherokee, and I was there trying to pull the head, but ran out of time. It is a TUPY head, so I am hoping to go back tomorrow and pull the head from that engine. I took an impact to get the head bolts out, but I was not able to get the rear bolts out. I forgot to take my breaker bar with me because I was rushing before they closed, and that screwed everything up. That engine looked good: coolant in the block, pretty clean valvetrain, and looks like it passed California emissions just last year (did some research on that Jeep). 

I am thinking of just rebuilding my Cj7 engine and adding the TUPY head with the cam that I have. I also have a Weber 38 DGES that I was going to install on the Jeep before I found out that the engine was bad. I would definitely like fuel injection, but I will have to keep it simple right now in hopes of being able to finish in time for my wife's birthday. I am waiting on the piston rings for the rebuild. I have main and rod bearings here already. 

As for an LS swap, that's definitely in the plans. I have a '72 Nova that I did an LSX/T56 swap on, and the efficiency and power of these engines is incredible. 

[jordan89oak]

Another question for you Moses. I am going to be installing a four inch Rough Country lift on the Jeep and was looking for heavy duty shackles. It seems like all of the "heavy duty" shackles are lift shackles. 1/2in. lift shackles are the smallest I can find.

What is your recommendation for shackles? 

[Moses Ludel]

Hi, Jordan...The 4.0L head does require mods to install it on a 4.2L block—not extreme but perform this work carefully.  There is much info online about the port modifications. 

Make sure you can adapt the intake manifold of your choice to the head.  If you plan to reuse the 4.2L intake manifold, be certain to position the manifold to port match with the cylinder head.  Get the exhaust manifold/header from that 'Grand Cherokee 4.0L—your earlier 4.2L exhaust manifold will not fit. 

Work through this head swap methodically:  1)  plugging the correct ports, 2) using an intake manifold that will match with the head (modifying the manifold pin notches as necessary), and 3) install the 4.0L exhaust manifold/header from the donor vehicle.  Do your homework to avoid issues.

As for the Weber, I'm not a huge fan though many have used them successfully.  The one caveat to follow is installation of a fuel pressure regulator.  Restrict pressure to the PSI recommendation that comes with the Weber carburetor kit.  The stock mechanical fuel pump is well above that pressure, which will unseat the float needle and cause flooding.

As for shackles on an eighties CJ, I recommend a shackle reverse kit at the front springs.  The stock front shackle frame brackets have a hole drilled in them to clear a frame rivet.  The shackle frame brackets fatigue over time and break at the rivet point.  I talk about this in my Bentley Publishers' Jeep® Owner's Bible™ and also my Jeep® CJ Rebuilder's Manual: 1972-86. 

Most front shackle reverse kits add a slight lift, so you need to adjust your spring lift kit plans accordingly.  Some shackle reversal kits are bolt-on, some require welding.  Years ago, we made these kits bolt-on, using the factory bracket threaded holes in the frame and reaching out to catch the front bumper bolt holes.  Use care removing the frame bracket bolts, they will want to shear.  AMC/Jeep® factory nuts in the frame tend to seize the bolts over time. 

See what's available in the front shackle reversal kit market.  Read reviews and consumer feedback before choosing a product.

Moses

 

[jordan89oak]

I have been looking at the required modifications for the swap and it doesn't look too difficult to do. Thank you for reminding me about getting the exhaust manifold. I would have definitely forgot all about it. I'm hoping to be able to go back tomorrow morning. I have read the instructions for the Weber carb and the need for a fuel pressure regulator. I still have to get that. I have looked into Rough Country's reverse shackle kit. It is a bolt on kit that requires some drilling to the frame for the front brackets, but definitely something I can handle. I am going to give them a call tomorrow to ask a few questions. I want to stick with their products since my lift kit came from them. 

Thank you so much for all of the help Moses. I will definitely have to pick up one of your books.  

[Moses Ludel]

You're welcome, Jordan...Glad you followed up on my comments.  You will find the hands-on Jeep® CJ Rebuilder's Manual:  1972-86 valuable.  I had your CJ in mind when constructing the book and prototype vehicle.  The Jeep® Owner's Bible™ will help you orient to your new "Jeep® Thing!"  I've been in and out of muscle cars since the sixties and wrote tech copy and the Tech Q&A column for Popular Hot Rodding from 1987-97.  We have much in common, including wives with birthdays in November!  Welcome to the Jeep® community.

Keep us posted on your progress and whether you make the Yosemite deadline next month.  Some cell phone photos of the cylinder head swap would be helpful to many.  (Start a new topic for that one!)  I'm guessing you do not have an emissions requirement for your Jeep®?  If you do, the 4.0L head would likely pass with the 4.2L intake and the OEM BBD carburetor with all emissions devices in place.  Did Weber get a California E.O. number for the carburetor?  The head by itself is a flow and anti-knock improvement, your incentive, I'm guessing, for making that swap.

Moses

[jordan89oak]

Thank you very much for the warm welcome. It is great to hear that you have been a part of the muscle car scene as well. I will definitely start a new topic on the build with lots of photos. 

California still requires emissions inspections on '76 and newer vehicles. I am planning on doing the smog using the OEM BBD carb, as Weber doesn't have a California E.O. number for their carbs. I did manage to get the head off this morning. The engine on that Jeep ('04 Grand Cherokee) looked like it was cared for pretty well. I kind of wish I would have just pulled the entire engine out, but I had to make it back in time for class. I have to take the head down to the machine shop to have it checked. I also managed to get the rocker arms, as I am not sure if the CJ7 rocker arms are the same.

Thanks Moses!

 

[Moses Ludel]

Jordan...I wondered about emissions as the Weber has never held an E.O. number.  I'm guessing you will be doing a complete emission legal engine conversion between the current smog inspection with the BBD and the next smog check due? 

I like your idea about the LS, here's a link to a 50-State legal LS swap into a TJ.  The approach would be similar.  California is tricky about the transmission and downstream emissions components.  The current CARB view is that the transplant engine is integral with its transmission and also requires all engine related downstream emissions equipment (OEM components from the donor vehicle) such as the converter(s):

https://www.4wdmechanix.com/HD-Video-Advance-Adapters-Jeep-TJ-Wrangler-LS-V-8-Conversion?r=1

Another, perhaps simpler approach would be a traditional TBI 350 V-8, 1987-95 variety.  I like this engine for its simplicity and torque, which is more than enough for a CJ-7.  Complete, it would not be complicated beyond the usual donor ECM and engine harness issues.  In addition to automatic transmissions, there is the manual NV4500 found in early nineties 3/4-ton and 1-ton GM trucks.  Painless and others make harnesses to simplify these swaps.  Curious where you go with all of this.

Moses

[jordan89oak]

Hi Moses,

I'm back for another update. Today, Sunday, I purchased a complete 4.0L Grand Cherokee engine. This engine also has the TUPY head and is complete, minus the engine harness and ECM. I would like to take advantage of the fuel injection system if I can come across a harness and computer. If not, I will have to put the carb intake just to make the trip in November. 

That LS article is great. I actually have an L96 engine on a stand that might make its way into the Jeep once I am done with law school and the BAR exam. I was saving it to drop it into my 1974 Corvette, but I just went with the original L82 engine and vortec heads for now. The car will be a gift to my dad, hopefully, for his birthday in December. 

I have read about the NV4500 transmission, and it sound like a really good option to go behind an LS engine. 

[Moses Ludel]

Jordan...You have the option here of doing a complete restoration of this 4.0L with or without your 4.2L crankshaft and a 4.6L buildup.  You could easily make this engine emission legal by restoring the PCM and wiring.  (See whether Painless has a harness for this conversion.)  If that performance level makes sense, you have what it takes here if the exhaust manifold is available. 

Your 4.0L find is a coil-on-plug engine that would require a PCM for a chassis with a matching coil-on-plug engine (1999-2006). An aftermarket 50-State legal (CA E.O.) exhaust manifold can be substituted.  The 4.0L would be considered an "engine change" into a CJ chassis, which does require a referee station for the initial smog inspection and testing. 

Here is a piece I did recently on diesel engine conversions with an in-depth look at CA engine change law.  Sift through for my comments regarding California emissions:

https://www.4wdmechanix.com/Cummins+4BT+and+4+ISB+Diesel+Engine+Conversions

Can you restore the 4.2L head to get by with the current 4.2L AMC/Jeep engine?  Reworking the head and installing new rings would do it if the cylinders are not tapered too much.  (If tapered too much, a ring change will be an exercise in futility.) 

You can remove the ridges then the rods/pistons.  Hone cylinders properly.  If you do this work in the chassis, use extreme care to cover the rod journals fully while honing.  Honing debris will quickly take out new rod bearings.  Clean all embedded debris from the honed cylinder walls.

If the pistons are reusable, clean them without using a wire brush, you do not want to damage or round the piston ring land edges.  Scrape the ring grooves carefully with a ring groove cleaning tool or a broken and shaped old piston ring—without removing aluminum.  Wear gloves to keep from getting lacerations when removing and installing piston rings.  

Buying time with the 4.2L would enable getting your 4.0L/4.6L or LS V-8 swap in order.

Moses