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Jeep 4.0 motor swap

J

JGlenn

Active Member
I have a 1993 jeep wrangler with a factory 4.0 with close to 200k on the clock and its just time for a new motor. I came across a deal an another 4.0 from a 2005 jeep wrangler with 16k on it and would love to drop it in. I plan to use the intake/exhaust maninfolds as well as the electronics off the 93 motor. This seems like it should be a direct swap but maybe im unaware of something. Does anyone know If im right or wrong about this ?

Justin
 
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Not that I know much about car stuff. But my 1995 Jeep Cherokee had the 4.0 high output in it and I sold it with 335 k on it and it still ran like a top.
These motors will run forever. Is there something wrong with it that you have to swap it out? 200 k is not alot on that motor.
 
Don't quote me on this because I haven't done it, but I own a '94 4.0 ZJ and I try to keep up on tech. The block should be a drop-in, although there might be differences where the tranny bolts up. Not sure. There will be sensor points in the new block that aren't used in the old one and should be plugged.

Don't use the old manifolds. The exhaust ones from the early '90s are crap and crack like crazy. The old intake is usable, but it's a popular mod in Jeep circles to use a '99+ intake for more power. You can use the new one as long as you make appropriate changes to allow the old sensors to fit the right places. And replace any sensors that have to do with engine timing, at that age they're getting iffy.

I think the ignition could be an issue. Newer 4.0s I believe use seperate coil packs with electronic controls, although I'm not sure if it's in concert with a mechanical distributor of some sort. Your old engine uses a ye olde distributor with electronic timing.

The later blocks are better, other than ones from a short period with head gasket failures. Earlier 4.0s are prone to piston slap and other odd but harmless noises. Later ones are braced heavily.
 
The motor bolts up the same as far as the transmission goes. Where you run into trouble on a jeep is doing a manual tranny swap from older to newer as they changed alot of things between '93 and '05. You can use your manifolds but as John says aftermarket intakes and exhaust manifolds will give you better reliability as the old ones crack easily and dont seal well when messed with. But as far as your original question it should work. The only concern i have is with the distributor. I think the '93 has one and the '05 doesnt as i think it has distributorless ignition. Good Luck!
-Tony
 
thanks for the input guys the motor I currently have in the jeep runs fine but the gear on the camshaft that runs the distributor is wated so it eats the dist. gear right up. I thought about just putting in a new cam but I was able to pick up this motor for only 300 bucks. I looked into an aftermarket and even stock replacement came and everything else I would need to do the job and it was easily going to cost twice that much. As far as the intake manifold I currently am running one off a 2000 and I plan to reuse it. I know all too much about the cracking manifolds as well last spring the stock one cracked so I put on a nice gibson header the same time I put on the 2000 intake but now that has cracked too. Im trying to get it warranteed since that it cracked right at one of the collector welds but if they give me a hart time i may just end up welding it back up myself
 
The 05 motor has almost a dummy dist. in it it just has the cam pos. sensor where the rotor would normally be and the oil pump drive at the bottom of the shaft. I bought a rebuilt one for the 93 year and it dropped right in to the 05 so hopefully im good to go here ?
 
Sounds like your good to go then from what you've told us. Just pay attention to any sensors you might have that are different on the block if any. Most of the sensors are either on the intake or exhaust manifolds so i dont expect you having any problems. Check your bracket mounting and bottom pulley also. Is yours an automatic or 5 speed? If a 5 speed check your pilot bearing as it may be different between the two. Since you've already had to change out distributors before i take it you already know how to set up your firing order and TDC. If from base (where it meets the block) down are identical including the gear on both the dummy and your rebuilt distributor, you should be fine. If your '93 block has a crank sensor mounted on the rear of the block (picks up off the flywheel) as some '93's had them, make sure you have the same hook-up on the block of the '05. Jeeps had a nasty habit of changing minor things from year to year from mid 80's on so keep a sharp eye out for any differences. Good luck!
-Tony
 
Yes, i've seen that but mainly in the 4cyl versions after they overheated. You know, the ones with the plastic valve covers...lord..who was the winner that thought that one up? Those you didnt change the gasket, you changed the whole cover or they would still leak. Some of the 4.0 and 4.2 engines had those too with the same results. Come to find out the heat messed up the timing chain guides (plastic) causing slack in the chain. Replacing the guides and chain cured it. I suspect something similar in the 6cyl engines as the rattle i hear in those sounds identical. The rattle never caused anything worse to happen that i've seen but it sure is annoying...lol! But the common link seems to be that they didnt rattle until they were overheated. And no...they all dont sound like that, only the ones that have been overheated do. Ironically they must have a tough head gasket on them as i only recall only having to do a couple in the 15 years i've worked at my garage. Usually the head had to come off for other reasons instead of overheating like burnt valves due to driving awhile with badly leaking exhaust manifolds. Go figure.. Most of the heating problems i've seen with these were from not getting all the air out of the cooling system after a flush or anytime the coolant was drained like water pump, heater core or radiator replacement. This happened especially in the newer ones but started in mid 80's. The older ones would bleed the air off thru the radiator cap and overflow tank if by chance there was some air left in the system.
-Tony
 
mine is a 5 speed and i had a custom pilot bushing made as the 05 motor had an auto behind it in the donor jeep. Also that crankshaft pos. sensor you mentioned gets mounted in the tranny bellhousing so that will be in the same place but i was told i need to use the flywheel off the 93 motor because thats what the sensor gets its refrence points from. I seem to think this should all just bolt right up but i have a jeep dealership guy telling me that even though that distributor fits in that i wouldnt be able to get it timed and would need to use all the elctronics and newer coil on plug style ignition as well as the 05 computer to make this run but that doesnt really make sence to me
 
I've done some similar swaps in Wranglers, but I'm trying to dredge up all the details from the haze upstairs.

I've experienced having to use the starter motor from the new engine. Never had any problems with hose / linkage routing. I've had to resort to chasing down an odball bellhousing to work with the eng. /trans. /c.p.s. combo.

If I remember anything more important I'll chime in usefully. ;)
 
have you tried running a motor that came with coil on plug ignition with the old style dist and singe coil ?
 
yea i'm a bit skeptical to just start ripping my old motor out which i know could be a strong runner with a new cam to put in this 05 motor. my friend had talked to some jeep guys that said it would be a nightmare and i would need the 05 computer and electronics but then i talked to a guy at hesco performance that said as long as i used my old flywheel and all sensors it would a real easy swap. I've had this jeep for a few years and i've had thoughts of selling it but it was my fathers for 10 years before that and id kinda feel bad just letting it go and i'd miss it. Not to mention i've got quite a bit of time and money into it and its just an all around fun and practical vehicle. I can really think of anything else thats a blast to drive in the summer and is unstopable in the snow. Ha my 85 buick regal with the chevy 350 swap sure sucks in the snow. Anyways im at kinda a loss here my dad seems to think I should just sell it since it would probably bring 5 grand or so and pick up another beater
 
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