motor frame mounts 4 cyl vs 4.0L 6 cyl

[jpfrogger]

I got another Comanche and this one is a 1988 4 cyl but I'd like to do the swap to the 4.0L as I already have the motor and trans. The question is are the engine motor mounts different between the 4 and 6 cylinder, I am guessing that the 4 cyl mounts the motor farther back in the engine compartment. And if so, does anyone have a set that they don't' need and would let go cheap? How about the radiator mounting, is it just a matter of removing the 4 cyl metal mounting brackets to install the 6 cylinder radiator? Any info is greatly appreciated. Thanks

[FxRacing282]

core and whatnot needs to be changed i believe... could be wrong though. and i think the engine mounts are in the same spot... it would make sense

[rockhardzj]

I have the 4.0L motor mount brackets that attach to the frame. Very good condition, if you need them.

[CWLONGSHOT]

The MM's on a 6 cyl and 4cyl WRANGLER is different. So I am going to say its likely the MJ's will also be different.

Although I have not had both MJ mounts in my hand at the same time.

 

CW

[1999MJ]

the 4 banger mounts are way diferent then the 6 cylinder. the 4.0 mounts are set forward a little more then the 2.5 but they bolt in the exact same location on the frame

[HellCreek]

I just changed the motor mounts on my 1989 Comanche 2.5 and my 1991 XJ 4.0, and they looked the same to me.

[CWLONGSHOT]

I just changed the motor mounts on my 1989 Comanche 2.5 and my 1991 XJ 4.0, and they looked the same to me.

 

Yes they do... BUT side by side examination will show the 4cyl are lower and narrower where the single bolt goes thru the mount to the motor. Where they mount to the frame mounts IS THE SAME.

 

CW

[HellCreek]

Thanks CW. I actually changed both of mine about 2-3 weeks apart, so I did not do a side-to-side comparison. They just appeared to be the same. Thanks for pointing that out. I might have tried to use the wrong ones later and had to return them.

 

Thanks,

Tom

[jpfrogger]

So does that mean that the frame mounts are the same and the motor mounts are different or vice versa? I just bought some frame mounts for the 4.0L so I hope they aren't the same as what I already have for the 4 cyl.

[CWLONGSHOT]

Seemed to be something in the sir here in CT a couple weeks back..... One of mine, two of my pops and TWO friends MM went all in about two weeks time!! We changed them all here., All but one replaced both and one was a 4cyl all others where the 4.0 6cyl.

 

My buddie with the 4cyl figured he would be cheap and put in a set made up from a couple used ones that where in good shape. his where completely separated. The 4.0 bolted in to the mount on the frame, but where too high and too wide to fit between the 4cyl's engine mount. We had both in hand and didn't immediately notice they where different!!! EASY TO DO!!!

 

CW

[comanchedude]

If you want to put a 4.0L in a Comanche that had a 4cy you must change the frame engine mount horns "thats what I call them"

the frame horns are diffrent and look diffrent as noted by 1999MJ

 

the rubber mounts (motor mounts) are diffrent but could be used, the 4cy is a smaller rubber mount but will bolt in the same.

 

So you need the frame horns "brackets" whatever you want to call them

from a 4.0L truck

[jpfrogger]

Thanks, that's what I needed to know and thought was necessary. Luckily, I've got a set of frame mounts headed my way. Now I think I will also need a radiator and necessary mounting parts. I've already got the motor, trans, transfer case, t/c mount, shifter, an engine wire harness from a 1990 XJ, and a new in-tank fuel pump for the MJ. Besides driveshafts, anyone have any ideas on what other parts I might need?