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Hobbs 85 CJ-7


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Still in work obviously but:

1993 GM TBI 350 (I got it through the CA referee...pretty happy about that.

1993 GM NV4500 (6.3:1) from same donor truck. 1/2 tons did come with the 4500...

Advanced adapter bellhousing and Novak adapter from NV4500 to D300

4:1 kit and twin stick on the D300 

"Front Low Only" mod to the D300

Tom Woods rear driveshaft

MORE front shackle reversal (not seeing much value to this yet...)

VANCO hydroboost system

OME 2" lift (not sure if done with this or not)

Genright aluminum fuel tank (w/ stock GM fuel pump modified to fit)

Genright flat fender kit, sliders, and rear flares.  Beautiful but very heavy.

Aluminum radiator from 4WP

Monsta-liner interior (very nice stuff, almost on par with professionally done)

Autometer liquid filled gauges

Various other stuff I can't remember right now...

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looks good.  like the ratchet strap!   i too added a twin stick kit to my D300-- the comprehensive kit from advance adapters.  Low front is fun but beware of serious axle wrap. Too bad its not easy to get 4 high front only w/out dropping the rear driveline.     Now get us some trail action shots... 

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as far as shackle reverse, Moses might better explain the pros and cons but i found it to greatly enhance the street manners (like that counts, haha) and trail handling.  OEM set up has the front and rear springs working against each other.  Getting them into the same cycle arc seems to make it more of a pleasure to drive and less harsh on components and passengers.  It may be necessary to look into tire clearance at rear of front tire opening.  MORE sells a cool 1" off set plate to move the front axle fwd (or backwards) to suit your needs.

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The ratchet strap has actually been replaced with latches now.  :)

 

I found a modification on-line that allows you to shift to front low only, rear in neutral.  I did it while installing the 4:1 kit and it actually works.  It now has N, 2 HI rear, 2 HI front, 2 LOW rear, 2 LOW rear and 4WD.   It also prevents cross shifting (hi range on one end low on the other).  It's one of those "Seems to good to be true" mods, but its works, and at no cost (other than time and tools). 

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nice!  i kept my factory gear set in the D300 because, otherwise, you get super low crawl or just 1:1 high range which is not much help.  Instead, added a Klune-V under drive to add an entirely new range of gearing.  Sometimes factory low is nice for general trail cruising above 15 MPH but when super low ranges are needed, i have several combinations.

 

 

edit:  aah, there it is...

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The MORE axle reversal kit actually moves the front axle forward about an 1" or so.  They also have a PS box mount that moves the box forward which I also installed.  I still need to get the hi-travel front driveshaft, so not ready for off-road pix yet...

 

I've only driven it on road so far, I just don't see any improvement in handling...in any case, its already installed, so we'll see how it works off-road.

 

I like your Klune V idea, but I don't have the wheelbase to go any longer with the NV4500.  My last CJ was an 8...I would kill to have it back.

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you might see performance gains in the bumps at speed.  I also noticed a more fluid cycling of suspension in big rocks.  another issue with SR is need of longer slip front drive shaft.  Im on my 3rd iteration to find the sweet spot-- prevent bottoming out and not separating the two front pieces--- have had both happen couple times and not a fun experience.

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Great exchange!  Terrific CJ Jeep, very clean work, you did a textbook swap of the V-8, CA legal, yea!

 

The immediate concern for me on the spring over is the caster over the arc of travel.  If you can keep the caster angle within norms over the full range of axle/wheel travel, spring-over can work. 

 

Driveline U-joint angles, always a concern, get offset if you use a CV at the transfer case end and try to minimize the pinion angle change.  Yes, you do want 4-5 (as much as 7) degrees positive caster at static height.  Work all of this out, plus the steering linkage angles to prevent bump steer, and you're on your way with a spring over. 

 

Years ago, I balked at the idea, but with 35"-37" tires becoming the "norm", what's the alternative for that degree of lift?  For 33", even some 34"-35" applications, the OEM spring-under approach can work once caster is correct.  If you use caster/leaf spring correction wedges, make sure they are steel and not aluminum.

 

Target bump steering, arc of caster angle over the range of wheel travel, use the correct shocks, the usual...Keep us posted!

 

Moses

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Moses, I did a shackle reversal,  not a SOA.  In road driving I haven't seen much difference in how it handles vs. the stock spring configuration, but haven't tried it off-road yet.

 

 I'm going to try to take the route of "big tires little lift".  I want to trim away as much of the rear wheel opening as possible (to still look like a Jeep not a buggy) ands see if I can get 35 or 37's in there.  Upgraded axles will be called for with this size rubber, a 4:1 kit and a 6.3:1 1st gear...

 

 

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The main gain of a front shackle reverse on a CJ-7, -5 or Scrambler (1976-up) is that the front axle "trails" from the frame, it does not anchor to the frame at the rear of the spring.  You will notice a substantial gain when off-pavement and pushing against larger obstacles.  Instead of the axle and springs driving all the force into the OEM frame anchors at the rear of the springs, the springs will be able to swing or pivot upward from your reverse anchor at the front (the "shackle reverse kit").  This allows the springs and axle to pivot easily instead of needing to compress the springs lengthwise before the springs and axle finally have no place to go but upward! 

 

This is a very wise upgrade if installed properly, and it works better on the highway, too.  The front axle trailing from spring anchors at the front allows it to track freely.  The stock configuration had the frame pushing the front axle along from the rear/anchor ends of the springs.

 

A glaring example of trouble caused by the OEM spring configuration is the 1972-75 Jeep CJ.  They did not have the frame integrity your later 1985 CJ has, and hard trail use would cause the frame to crack or break just rearward of the stock front spring anchors.  This was caused by the severe force applied to the frame at that point when the vehicle pushed against obstacles.  In part, it was also due to the poorly designed frame:  The frame was boxed from the front bumper to just behind the spring anchors, then opened to a C-section.  The failure was at the junction between the boxed section (anchors) and the open channel rail. 

 

Note: Many CJs of this vintage have repaired/welded frames, we can discuss the best repair technique if anyone has this issue.  I'd be pleased to handle this in the welding forum.

 

As a point of interest, the M38A1 military equivalent to the original CJ-5/6 has the front spring anchors at the front of the springs.  My earlier Jeep CJ Rebuilder's Manual: 1946-71 features a 1955 CJ-5 that I restored and built up for the book.  That earliest edition CJ-5 came with the M38A1 type spring configuration—a factory "shackle reverse" if you will!  Can't explain why Jeep reverted to the MB/flat fender frame approach. 

 

Big tires, littler lift is a trend now, and it does help with the center-of-gravity and roll center, for sure.  The frame height for approach, departure and break over angles does not work as well as a chassis/suspension lift.  If you have enough approach, departure and break over frame clearance for your purposes, the "body opening" can be a smart way to go!  You will have the axle clearance "lift" of the big tires, especially 37" diameter.

 

Consider long-term planning around axle width for track increase.  Like RareCJ8's Scrambler, a radical lift is offset by a wider track width, in his case it's the use of stock, full-size 3/4-ton truck axles.  This wider track helps restore center-of-gravity from the dramatic chassis height increase.  Wider track also helps with any degree of body lifting that can affect roll center and C.G. 

 

If you plan to stuff 37" tires under that CJ, a wider track width may be a necessity for tire clearance and also can help restore vehicle stability.  This goes back to your comments about the J-axle—would it be wise to maintain that full track width? 

 

Could you configure spring perches for each side to center up that axle under your CJ-7?  A D44 J-axle at the rear could be a match.  Is the other end of that Wagoneer available?  That 6-bolt wheel pattern is a common G.M. 1/2-ton 4x4 truck and full-size Jeep configuration, aftermarket wheels are still readily available...make sure the hub center fits!

 

On that subject, I unearthed a simpler fix for your 6-bolt to 5-bolt issue.  Biggman100 brought Roadkill to our attention, and they have adapters for 6- to 5-bolt in your 5 on 5.5" configuration.  Here's a link:

 

http://store.roadkillcustoms.com/6-lug-to-5-lug-wheel-adapter-6-x-5-50-to-5-x-5-50-wheel-bolt-pattern/

 

Adapters would also increase track width somewhat, without the need to use wider axle assemblies.

 

Moses

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Thanks for all the input Moses, and everybody else.  I actually used to have a 1956 CJ-5 that did have the factory M-38A1 style "reversed" front shackles.  Moses, I'm sure you don't remember it, but I actually wrote you a couple letters back in your "Holy Moses" (that's right isn't it?) days for "Off-Road" magazine.  You answered both and I remember thumbing through the magazine at a book store and thinking "man this guy has the same exact problem I have!"  I still have the magazine.

 

I will investigate the adapters, that would definately be easier, I'm an old dog, but I can learn new tricks.

 

I have an unexplainable dislike for full width axles on CJs, I guess I should re-visit that.

 

(stupid thing is that as I have been expecting to discard the Waggy outers I have let the spindles rust in the rain.  Never assume I guess...

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The shackle reversal is the MORE weld in unit.  Very nice stuff.  The only tricky part is getting the 1 1/4" (as I recall) hole drilled straight through the frame.  I pretty well achieved that, had to use an observer to stand back a bit and eyeball that the drill was straight.

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You will like the shackle reverse...So will your Jeep's frame and front axle!  You can feel the handling difference, both on- and off-highway...

 

Pleased that someone remembers the Argus OFF-ROAD days, I wrote the "Holy Moses!" column for 12 years (1985-97).  The column's name was Editor Rick Sieman's brainstorm.  If you recall the questions you sent me, I'll likely remember our exchange, Hobbs! 

 

Well, we may be longer in the tooth, but we're still in the game.  The Honda XR650R motorcycle is my latest "exercise machine"...It even came with a cardio workout: kick starting a thumper at 10.5:1 compression ratio.  This takes me back to 1971, a dozen years before my first article appeared in the February 1983 issue of OFF-ROAD.  I bought a used '69 BSA 441 Victor Special, another thumper, and it, too, had a compression release lever for starting...

 

Though this certainly shows my age, I'm pleased to share that I passed the XR650R stress test and am still here to share at the forums!  As my brother-in-law would say, "I'm an 18-year-old brain in a 64-year-old body!"

 

Moses

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I do remember at least one of the questions.  I was putting a Buick V6 to a T-18 in my 80 CJ-7.  I couldn't get the clutch to work right, it would either not fully disengage (hard to shift) or if adjusted to fully disengage, the throw out bearing would stay in contact with the disk and spin forever.  You noted I had one of the Skylark bellhousings, with a reverse acting (forward throw) release arm.  You suggested finding a standard rear-operating assembly as they required less throw.  I finally found one and it worked!  Many Moons ago.   You and Granville King were my Jeep heros back then...

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We did have a fun and engaged 4x4 community in the '80 and '90s...Do recall this question, I enjoyed troubleshooting and drilling down in the parts sources, using cross-reference manuals and all...That was ground school for the Bentley books...

 

A friend introduced me to Granville King's daughter, she's now at the Reno Area.  I suggested we do an interview, she has myriad stories about the days with Granville, Mexico, the desert and all.  There's a unique story here.

 

You've maintained your keen interest in Jeep, too.  Wonder how many of us are still out there 'wheeling from that period?

 

Moses

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time line question:

 

when did the popularity of airing down one's tires for serious trail work happen?  I recall many, many 4x4 trips all over difficult trails from 1979 forward and we never though of, saw others or heard to air down.    then one day in perhaps 1995 someone suggested it and bright lights went off in my head.  What a game changer.   And in the early to mid 80s, 33" tires were considered monster meats, LOL.

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In the 'sixties through 'eighties, airing down was a sand wash or dry beach technique.  I went over the Rubicon Trail many times without airing down, but as you know, that's granite and good traction. 

 

Airing down became a mantra and ritual by the late '80s.  I would like to emphasize my time-honored concern over airing down:  The tire's capacity to bear weight decreases with the lower pressures.  For heavy vehicles, in particular, the fashionable "let's air down" can leave sidewalls and tire carcasses vulnerable to damage, belt separation and failure. 

 

On the other hand, the use of dramatically oversized tires, especially Load Range D and E one-ton truck equivalent tires on a trail Jeep, offers so much overkill in weight bearing capacity that airing down, within reason, is not much of a hazard.  For a lighter weight vehicle, you still have excess load capacity, even with air pressures down. 

 

Everyone has an airing down opinion.  Based strictly on tire stamina, I limit airing down to no less than 15 PSI in the extreme, preferably 18 PSI or higher.  I don't drop below 15 (for sand) even with oversize tires, as the load on the sidewalls and mounting strips of the tires becomes perilous at lower pressures.  Elaborate bead locks and other creative devices allow dropping pressure to the point of radical tire distortion.  18-20 PSI works for me.

 

Moses

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Great answer Moses.  I'm experimenting on an even more detailed air down tactic.   Often the rear is carrying more load than front axle, so i find a little more psi in rear and less up front makes a difference.  As a bonus, i find if there is a differential between front and rear, there is less wheel hop on steep climbs.  Average Rubicon run?  15 front, 18 in rear.   Now, if we all could have CTIS for our 4x4 axles, its then just a matter of momentary switches and gauges on the dash to dial it in...

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I never have done much airing down except at places like Pismo.  Basically I'm too lazy.

Anybody else have a "chuffer" pump?  Spark plug pump...it actually works pretty well, but newer fangled engines probably don't like running with a plug removed.  I use it as a novelty to get people talking once in a while.

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I recall the spark plug pump, another yesteryear invention...Always puzzled over whether there's a way to filter the chuffer pump air, or are you stuck with inflating the tire with a nice mixture of fuel/air?

 

This device works well on engines with accessible spark plugs, like your later CJ Jeep inline six.  Imagine this chuffer device with a Liberty 3.7L V-6, a 4.7L V-8 in a Grand Cherokee or a JK Wrangler 3.6L Pentastar V-6 and their aluminum thread, barely accessible spark plugs!  Time for a big, 12-volt powered pump in either of those cases!

 

Have JK Wrangler owners given up on the York compressor conversion and other traditional, high volume, engine driven air supply solutions?  What's popular currently?  Anyone want to open a new topic/thread on this subject? 

 

Moses

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The spark plug pump only uses engine compression to drive a little diaphram.  It actually pumps clean air, and pretty quickly.  Makes a racket though, banging away with each compression stroke.  Burned fingers are not worth it, it's just a conversation piece, although does work if needed. 

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Hobbs, thanks for qualifying...That makes sense and allays my concern, I'll no longer wonder whether chuffer pumped tires are rambling down the road with a perfect mixture of gasoline and air inside, just waiting for static electricity or enough road heat to ignite them!  This does make perfect sense...

 

Moses

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  • 10 months later...

I've been looking into the Oasis onboard compressors myself. They are right down the street from me, so I've got to see them in action. At 12V, wide open, they actually gain in pressure!

Add in the fact that you can run them at 24V, and you got yourself a winner. Downside is cost! They're big bucks!

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