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Unread 11-25-2010, 04:49 PM   #1
Natethegreat569
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1986 MJ Comanche 
 
Join Date: Sep 2010
Location: Ocala, Florida
Posts: 70
My 1986 Jeep Comanche X

Ok so here's the scoop. I bought this truck about 3 months ago for $950. For what I paid I'm sure getting my use out of it. It has the 2.8 V6 carbed. Its 2wd and runs decent.

Now here's the bad part.
It leaks oil like no tomorrow.
Has almost no power.
It's only 2wd.

Ok. Here's the next part. I'm wanting to do a lot of mods but I'm not sure what to do. I'm thinking about starting out by getting a beat up but mechanically sound cherokee and swap out engine, tranny, and axles. I'm pretty new to all of this mechanical stuff but I'm excited to learn.

If you have any suggestions on what I should do for mods let me know. I'm low on money but I'm saving up.




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Unread 11-25-2010, 11:24 PM   #2
tbburg
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2000 XJ Cherokee 
 
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Location: Scottsdale, AZ
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Sweet looking little truck.

A big chunk of the reason you're down on power is the tires. Those look like 30"s or 31"s. The stock tire was about 28". As the 2.8 is only marginally more powerful then the 2.5-4cyl(maybe 5hp, depending on year), unless it's been re-geared,(doubtful) you'll really notice.

Bad news: the XJ/MJ engine compartment was redesigned to fit the 4.0 in '87. Shoe-horning the 4.0 in an earlier MJ is do-able, but not a direct bolt-in swap. Firewall mods needed. You're on the right line looking for a complete doner vehicle to do it if you so choose. If you go that route, you also need all the wiring for the engine(and trans if it's an automatic)

A possible engine swap is the 3.4L out of a Camaro (the early fuel-injected model) Same engine family. you can either use the Camao wiring and graft it in, or Painless wiring makes harnesses for most GM motors.
Another (overlooked) possibility would be to get the power train out of a 4-cyl. Cherokee. Everything is bolt in, and the 2.5 can easily be built to 150-160 HP - almost the power level of the 4.0, and a couple hundred lb lighter in front.

Don't get all down just because it's not 4wd. You don't NEED 4wd:

(thumbnail is link to full-sized photo)
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"Never attribute to malice that which can be adequately explained by stupidity, but don't rule out malice."
My other car is also a Jeep,.. and so is the other one,.. and that one too. How many do you own before it's "a herd" ?
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Unread 11-26-2010, 12:48 PM   #3
Natethegreat569
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1986 MJ Comanche 
 
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Location: Ocala, Florida
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I really wish my truck looked and performed like that one.
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Unread 11-26-2010, 03:16 PM   #4
tbburg
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For a good, inexpensive axle upgrade, scour the junk yards for a 4-cyl. Comanche(preferably), Cherokee, or a Ford explorer with rear disc brakes. you have to research the Ford to find the right gear set(4.10), but all the 4-cyl XJ/MJs came with 4.10 gears(or very rarely lower) That'll get some power back. Both the Cherokee and Ford axles would require welding spring perches on to bolt under the Comanche, and the Ford would require modification to make the brakes work, but the Ford 8.8 rear axle is a great upgrade.

You can do a inexpensive "budget boost" lift and get it up a couple inches for under $100.00. Here's a link for the Cherokee version:
Home Brew Budget Boost
For a Comanche, you use a set of S-10 or Dakota leaves in the rear, and follow the front instructions to the letter.
Here's a recent thread on the subject:
http://www.jeepforum.com/forum/f53/c...heels-1117177/

Quote:
Originally Posted by Natethegreat569 View Post
I really wish my truck looked and performed like that one.
No,...
You don't.

'08 BITD Vegas-to-Reno 500 - DNF - Crapped out at about MM 260 - holed oil pan - alternator failure(quit charging, then bearing fail/locked rotor) -

'09 BITB Parker 425 - DNF - Died at MM 126 - Holed oil pan(twice) - broken shock mount(as in off the truck) - ignition failure (water intrusion). (This one really chapped, due to race rules, if we went about 4 miles further, we would have placed 2nd in class,... as it was, DNF)
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"Never attribute to malice that which can be adequately explained by stupidity, but don't rule out malice."
My other car is also a Jeep,.. and so is the other one,.. and that one too. How many do you own before it's "a herd" ?
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Unread 11-26-2010, 04:54 PM   #5
Natethegreat569
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Damn that sucks. I wish I could get out on the trails a little with my truck.

I was thinking about maybe putting a small block 350 into my truck but I'm not sure what transmission I should look for to go with it.
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Unread 11-26-2010, 10:40 PM   #6
tbburg
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SBC is a fairly easy swap. As you're fooling with a truck, you don't have to worry about trans length. Anything will fit. The trans for a SBC would be the TH-350 or -400(3spd) or the TH700-R4 or 4L60(4spd OD)
I'm a little un-sure of the GM terminology, but I think the 4L60 is the hydraulic version, and the 4L60E is computer controlled Any of 4WD versions of those transmissions will bolt to a Jeep transfer case(GM used the NP transfer cases too)

I just realized you have 2 threads running, and I'm responding to both of them,... oops!
To avoid confusion, in the future, I'm only going to talk about power train mods in this thread and suspension on the other one.
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"Never attribute to malice that which can be adequately explained by stupidity, but don't rule out malice."
My other car is also a Jeep,.. and so is the other one,.. and that one too. How many do you own before it's "a herd" ?
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Unread 11-27-2010, 04:33 PM   #7
Natethegreat569
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any idea on a cost estimate for a sbc and transmission? and how much adjusting will I have to do to get the sbc to fit? any suspension changes need to be made for weight?
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Unread 11-28-2010, 07:17 PM   #8
tbburg
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Never tried to buy anything automotive-related in Florida, so I can't help much on a cost estimate. Craigslist, or the local junk yard.

One thing I didn't really specify but need to: Any transmission you get NEEDS to be the 4WD version. While you can convert a 2wd trans to the 4WD version, the process costs damn near as much as a new transmission.
Also left out, if you want a standard trans, the NV-3500 5-spd out of an S-10 is the same transmission as the NV-3550(used in the 00-01 XJ, and '00-up TJ), except it has a one-piece cast bell housing/trans case. Dodge also used a version of the NV-3500 with the 5.2-5.7(318-360)bell housing if you want to go Mopar instead of GM

I've read a couple threads on SBC swaps, and they didn't have to cut anything out to get the V-8 in there. Conveniently, the 4.0 weighs more then the SBC, and the weight sits further forward in the chassis then a V-8 would, so any spring for the 4.0 Cherokee works fine with a SBC conversion, you just get a little more lift.

Here's a pic thread from over on NAXJA. Guy fitted a SBC/700R-4 into a Cherokee. It's an '86, so your Comanche should be the same.
New guy and project pics - NAXJA Forums -::- North American XJ Association
He didn't futz around with electronics, just the old-school HEI and a carb.
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"Never attribute to malice that which can be adequately explained by stupidity, but don't rule out malice."
My other car is also a Jeep,.. and so is the other one,.. and that one too. How many do you own before it's "a herd" ?
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Unread 11-29-2010, 08:24 PM   #9
Natethegreat569
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ok I do have one more question. I've looked under my truck a few times and realized I have a ridiculously huge driveshaft, like diameter wise. Its even bigger than my friends 80' toyota cruiser. any way to identify it? I'll try to get a pic of it soon.
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Unread 11-30-2010, 03:40 PM   #10
1986Comanche
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Quote:
Originally Posted by Natethegreat569 View Post
ok I do have one more question. I've looked under my truck a few times and realized I have a ridiculously huge driveshaft, like diameter wise. Its even bigger than my friends 80' toyota cruiser. any way to identify it? I'll try to get a pic of it soon.
All 1986 Comanches have the really big rear driveshaft, My 1986 Comanche has the really big rear driveshaft as well. I hope this info helps.
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Unread 11-30-2010, 04:00 PM   #11
1986Comanche
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Quote:
Originally Posted by tbburg View Post
As the 2.8 is only marginally more powerful then the 2.5-4cyl(maybe 5hp, depending on year)
The 2.8L V6 is not more powerful than the 2.5L I4. The 2.5L I4 has 117 HP while the 2.8L V6 has 110 HP. The 2.8L V6 does have a little more torque though. The 2.8L V6 has 145 lb ft of torque while the 2.5L I4 has 135 lb ft of torque. What do you mean depending on year? The 2.8L V6 was only offered in the Comanche in 1986. I hope this info helps.
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Unread 11-30-2010, 04:25 PM   #12
Natethegreat569
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would it be possible to use my driveshaft for a sbc 350?
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Unread 01-08-2011, 03:09 PM   #13
cheese_man
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i would recommend that you swap a chevy 283 or 305 v8 engine

should be readily available at any wrecking yards and should just bolt right in
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Unread 01-08-2011, 04:23 PM   #14
Pete M
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Quote:
Originally Posted by cheese_man View Post
i would recommend that you swap a chevy 283 or 305 v8 engine

should be readily available at any wrecking yards and should just bolt right in

are those 60* engines or 90* engines?
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-88 MJ; 4.0L, ex-2wd, TJ ax15/231, 78 Ford D44 w/spool, 9" w/posi, 33" trXus MTs, custom roll-bar/bumpers/etc.
Also an 86 MJ Metric ton and 2 '90 MJs
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Unread 01-09-2011, 12:16 AM   #15
tbburg
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All Chevy V-8s are 90deg. architecture.
The 305 is the low performance base V-8 offered in earlier (late 80s and back) They generally had either a 2-bbl or TBI. Not a ton of power, but not a bad motor.
The 283 is obsolete and you're not likely to find one in a wrecking yard any more.
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"Never attribute to malice that which can be adequately explained by stupidity, but don't rule out malice."
My other car is also a Jeep,.. and so is the other one,.. and that one too. How many do you own before it's "a herd" ?
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