Jeep motor swap

deerhound

New Member
Joined
Jun 2, 2010
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Scotland Neck
Looking at buying a 84 jeep CJ 8 it has a 4 cylinder in it currently. What can I put in there to replace it. Will a 258 bolt right back in or will it require modifcations. What are my option without spending a lot or doing major changes. Do not know anything about the 4 cyl. are they dependable and strong enough for the jeep
 
cj8

Pretty sure that you will have to change the motor mounts, different radiator, (depending on what transmission it has in it) the tranmission bellhousing, and or driveshafts, and even possibly re-gear the axles. Again depending on the transmission and what size tires you are planning on running. But I bet there are some guys on here that can help you with all these items. Me personally if you were going through all this trouble I think I would just do a V8 converson. AMC or other.
 
I think 1984 has the AMC 4-banger, earlier 80's used the GM Iron Duke. One is 150 cid, the other 151. Supposedly the GM engine was OK for a carbed 4-cylinder, but the AMC leaves a lot to be desired...even though its the base for later 2.5L MPI engines used all the way til TJ/XJ exit.

I think the 1980-86 258s will bolt right in to the tranny, but the its probably a weak T4 or SR4 that should be replaced with the engine (assuming manual, not sure about the autos). Keep the D300 t-case, find a 258 with T176 if you are alright with a 6-cylinder...or go 4.0L swap. The engine mounts between 4 cyl, and 6 (including 4.0L) might be the same, can't remember. Radiator is different.
The bonus with 4-banger is that CJ-8 should have 4.10 widetrack axles, not the crappy 2.73 gears AMC used with 80s model I6 CJ's.

AMC V-8 swaps require at least one motor mount change from I6 setup, pass. side IIRC. You will need adapters to get the D300 to fit behind any stock AMC engine/tranny combo.
 
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