anyone think its possible to rebuild 88 xj 4.0 with out pulling motor it is lifted so clearing oil pan and having room to work is not an issue. just would like hone, new rings, rods and main bearings, just know it will be a nightmare trying to remove the engine when i did head gasket cyl walls were in great shape no scoring ....
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engine rebuild??'s
- Thread starter 1slowxj
- Start date
notamos
NAXJA Forum User
- Location
- Fort Collins, CO
Not planning to pull the crank? If you are going to hone it, pull it. Too much metal particulate for my tastes. Do it properly or don't bother, IMO.
mcnamaag
NAXJA Forum User
- Location
- Red Lion, PA
How will you clean the oil passages? What's the reason for the rebuild? If its for mileage, low oil pressure, noise? Any of these issues really require the block to be cleaned. If not you're throwing money away. All that crap, metal shavings, carbon,etc will just get circulated threw out the rebuilt motor.
FWIW
FWIW
diggerdave
NAXJA Forum User
- Location
- Bend, Oregon
it is possible to do a rebuild without pulling the motor (I'm doing mine right now with the block still in the car) do be careful of where debris is going though and keep things as clean possible. Pulling the block is always the best option but if for whatever reason you can't it can be done in the jeep..
i've got a pretty nasty rear main leak which i believe is causing me to lose oil pressure after running 10 minutes or so i have a dollar bill size puddle...so i've gotta pull it all apart, i did a compression test on it and cyl's very between 110 and 130 with a wet test they increased dramatically so rings are tired..figured what the hell lol half way there might as well do it all
cruiser54
NAXJA Forum User
- Location
- Prescott, Az
Rear main seal leak will not cause an oil pressure loss.
bulrid8
NAXJA Forum User
- Location
- upstate,sc
cruiser54
NAXJA Forum User
- Location
- Prescott, Az
What's "dramatically"?
cruiser54
NAXJA Forum User
- Location
- Prescott, Az
Again, what are the numbers cold, hot, idle, driving?
What brand of oil filter are you using?
Does the engine burn oil?
on start up i'm right around 60 psi by the time i get to the trails which is about 10 miles from where i live my gauge is flirting with 10 psi and seems to level off there all through the rpm range, ii have a purolator classic filter on it running conventional 10w-40, never really had problems with burning oil always had more blow by than anything
cruiser54
NAXJA Forum User
- Location
- Prescott, Az
I think you should use a mechanical gauge and verify the readings before going any further.
alright finally had some time to hook up mechanical gauge it confirmed factory gauge 
but on the bright side i had a chance to grab a 94 h.o. motor for next to nothing out of a friends rig! being a renix i believe i need to use my head intake and exhaust but now i can do a full rebuild any suggestions on either route?
but on the bright side i had a chance to grab a 94 h.o. motor for next to nothing out of a friends rig! being a renix i believe i need to use my head intake and exhaust but now i can do a full rebuild any suggestions on either route?
sidriptide
nobody of any consequence
- Location
- western massachusetts
if the HO motor was running fine i'd leave it alone for the most part. clean it up, and do the mechanical stuff you don't want to do with it installed in the vehicle. full gasket kit, new oil pump, new timing chain, rear main seal, oil filter adapter o-ring, personally i'd do a new performance cam while i'm in there just to bump the torque a little. do it all while it sits on the engine stand. if compression is fine leave the cylinders alone.
cruiser54
NAXJA Forum User
- Location
- Prescott, Az
alright finally had some time to hook up mechanical gauge it confirmed factory gauge
Want the right answers on putting that HO into your Renix?
Here ya go. Easy.
Cruiser’s HO into Renix Swap
This swap is easier than some will lead you to believe, generally those who have never done it. Those of us who have done it, like myself, will share with you the things that need to be done for a successful swap. Just think of it as swapping in a long block.
The HO and Renix have some differences but none that can’t be overcome very easily.
Any HO engine from an XJ or ZJ through 1999 can be used. One running change was that the rear of the head was no longer drilled and tapped for the temperature gauge sender beginning in the 96 model year. The sender can be relocated to the threaded hole in the thermostat housing taken from the HO engine. You’ll have to extend the wire to that location. Some brave souls even drill and tap the HO head for the sender.
You will be using the intake and exhaust manifolds from your Renix, along with all your sensors and wiring. Since the intake ports of the HO are slightly different, you use the Renix gasket. Exhaust ports are identical.
You will need to use your Renix distributor as it is different than the HO because they use different fuel management systems. The flywheel or flexplate from the Renix must be used so your CPS gets the correct signals. The valve cover from the Renix allows you to keep your CCV system intact and requires no modifications.
The HO block will have a plug in the coolant galley on the driver’s side of the block, closest to the front, which needs to be removed so your Coolant Temp Sensor can be installed in it’s place just as it is on the Renix. It requires a 5/16" square drive or a modified 3/8" drive that has been ground down to fit. Do this before installing the engine.
As for the knock sensor, which is located just above the oil pan on the driver’s side of the engine about mid way, all the blocks I’ve seen are threaded for it. If not, I’ve heard they may be drilled but not tapped. Tap the hole if that’s the case.
Revised 03/28/13
alright im taking cruiser's method and building this motor put all new rings bearing melling hv oil pump shaved .011 off heads to bump up compression a little and went with mopar performance gaskets maybe mustang injectors...?? we will see how it plays out
alright motor is built set it in the jeep fired right up but has a horrible idle and if give throttle the motor just backfires like timing is off. now i am positive that timing chain sprockets are aligned correctly and that distributor is in right spot...when i through the timing light on it the ecu seemed to be whats throwing it off it starts to have intermittent spark not as constant as it should distributor,cap,rotor,plugs and wires are all new im really at a loss here.... any ideas??
winterbeater
NAXJA Forum User
- Location
- Royal Oak, Michigan
I'd try turning the distributor a little bet at a time first.
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