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CJ7 motor swap options

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Toad

Well-Known Member
Location
Millville(logan)
My 1985 cj7 currently has 4.2 with howell efi, t5 trans, and dana 300 with 4 to 1 gears. Motor has a lifter tick when cold other than that it runs fine. I use this alot off road. In the rocks the gearing is perfect. Problem is normal street driving and mud or snow it is a complete dog. Motor has no top end power.

So 1st option is I have a 1995 4.0 removed from a ZJ 130000 miles compression at 160 psi.

2nd option is a vortec 4.3 out of 1995 jimmy. 230000 miles. Have not checked compression but runs good.

I will be swapping to ax15 with either motor.

I have never driven a 4.3 in a jeep. I think the 4.3 will get better mileage. Have a higher rpm range and less low end grunt. I dont think it will be a issue with my gearing.

Just looking for any suggestions or recommendations.
 
Cherokeester

Cherokeester

Registered User
Location
Wellsville Utah
Honestly I don't see a huge improvement with either of those two engines. If you want the grunt, find an amc 360 with a t-18 on it, get an adapter for the dana 300 and you will be golden. I put a 401 in mine and it will do a wheelie if I wanted. The ax15 is a long tranny as well.
 
T

Toad

Well-Known Member
Location
Millville(logan)
If I were to do any v8 swap it would be a 5.3. Yes the ax15 is longer than any 4 speed. It will be about 1.5 inches longer than my current setup. Josh tell me about you 5.3. Not interested in the 4l60e
 
RockChucker

RockChucker

Well-Known Member
Location
Highland
Ls motors are where it is at. Just finished putting a 5.3 in my TJ about 6 months ago. Tons of low end and the top end is incredible. I am also running an AX-15.
 
idahoyj

idahoyj

Well-Known Member
Location
Twin Falls Idaho
mbryson

mbryson

.......a few dollars more
Supporting Member
Location
Bountiful, land of rocks
Bart said:
As long as you're doing a different motor, do a 5.3 or 6.0.
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T


This

Of your choices, I wouldn't bother with swapping to a 4.0L or a Chev 4.3L. They really won't be much if any better than what you have and you'll put a lot of work into the swap without much if any return.
 
L

larrybenny

larrybenny
Location
Salt Lake City area
I did a 5.3 conversion with beefed 4L60E in my 91 YJ. Love it and the power. I get 21 mpg even putting my foot into it a lot. Runs perfect at any elevation and at any angle. These engines come stock with about 325 HP. Very reliable, no issues for the last 2 1/2 years and 32,000 mi.
 
Maverick

Maverick

old-school
Location
Anywhere, thanks to my geeky droid
Bart said:
As long as you're doing a different motor, do a 5.3 or 6.0.
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What he said. I'm getting a '91 YJ for my son, already looking at a 5.3 to swap in. Jeepin4x4james has a 5.3 w/ 4l60, and it looks like idahoyj does too.

I agree with Marc, bang for the buck swapping in a 4.0 or 4.3 just isn't there. 5.3 or tbi350 or (ahem) tbi454 is the way to go.:D

What axles do you have?
 
RockChucker

RockChucker

Well-Known Member
Location
Highland
Toad said:
Any overheating issues?
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Nope. None whatsoever. I have a big griffin radiator and spal electric fan that is computer controlled. My temps never get much past 210.

Team1k said:
If i may hijack a little, what did this conversion end up costing?
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Cost is a hard thing to compute. I know what it cost me, but I shopped around a lot and collected parts for more than a year before I started anything. I also did the swap by myself.

The most economical way to do it would probably be purchasing a wrecked donor vehicle that you can pick up for not much more than the engine, PCM and harness will set you back. That way you can sell off what you don't need and break even or make money on that part. Adapters and brackets are a significant cost and are fixed unless you can make them yourself. The thing that really gets you is all the little things. A few bolts here a wire connector there. It all adds up. And if you pay a shop to do it, expect to pay somewhere between 5 and 10 grand just for the install labor.

The swap is not terrible though if you research what you are doing before you even begin collecting parts. Take your time and do it right the first time.
 
Caleb

Caleb

Well-Known Member
Location
Riverton
IMO, it'd be a waste of time to swap any motor in with 160K or 230K unless maybe it was a 4bt (or similar) :D That's a ton of miles on any gas engine, even if they were cared for, let alone if they weren't or it's unknown.
 
Team1k

Team1k

Active Member
Location
Lehi
rockchucker said:
Nope. None whatsoever. I have a big griffin radiator and spal electric fan that is computer controlled. My temps never get much past 210.



Cost is a hard thing to compute. I know what it cost me, but I shopped around a lot and collected parts for more than a year before I started anything. I also did the swap by myself.

The most economical way to do it would probably be purchasing a wrecked donor vehicle that you can pick up for not much more than the engine, PCM and harness will set you back. That way you can sell off what you don't need and break even or make money on that part. Adapters and brackets are a significant cost and are fixed unless you can make them yourself. The thing that really gets you is all the little things. A few bolts here a wire connector there. It all adds up. And if you pay a shop to do it, expect to pay somewhere between 5 and 10 grand just for the install labor.

The swap is not terrible though if you research what you are doing before you even begin collecting parts. Take your time and do it right the first time.
Click to expand...


Yeah that was what i was afraid of. Everytime i start thinking about doing these swaps i get turned off by how expensive it will be considering i can get a brand new 0 miles 4.6 stroker that just drops into my YJ for $3000, no special parts needed besides new injectors. I wouldnt be making as much power though(260hp). Decisions decisions.
 
Tacoma

Tacoma

Et incurventur ante non
Location
far enough away
You could easily do an LS swap for $3k or less if you were smart about it. :D You could also spend over $10k without much work either, all depends on your skill vs. money vs. time ratios.
 
T

Toad

Well-Known Member
Location
Millville(logan)
The 5.3 is very tempting. I am good friends with the novak guys. I have the resources for the swap. They have a 5.3 4l60 cj7 that they have been trying to get me to go for a ride in. I have always turned it down. Afraid it would seal the deal :) I am cheap. I have thought the best way to get the motor would be buy a wrecked truck. Need someone with insurance auction connections. Unfortunately buying the 5.3 is the cheap part. It is motor mounts, headers, radiator, fuel system, custom flywheel, ecm and wiring that get expensive.
 
Maverick

Maverick

old-school
Location
Anywhere, thanks to my geeky droid
Toad said:
The 5.3 is very tempting. I am good friends with the novak guys. I have the resources for the swap. They have a 5.3 4l60 cj7 that they have been trying to get me to go for a ride in. I have always turned it down. Afraid it would seal the deal :) I am cheap. I have thought the best way to get the motor would be buy a wrecked truck. Need someone with insurance auction connections. Unfortunately buying the 5.3 is the cheap part. It is motor mounts, headers, radiator, fuel system, custom flywheel, ecm and wiring that get expensive.
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Tell me about it. I just spent a half hour perusing the Novak site looking at their adapters and reading through the YJ installation. Part of me wants to keep the YJ stock, since it's just flat less expensive, and part of me wants the vroom vroom factor, but that will mean different axles for sure. I suppose I could swap in the stuff from the Rainbow Relic... bwahahhahaha
 
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