engine differences/reliability

[collegeoffroad]

done a few searches around and read the dr. dyno writeup, but would like to know a bit more.

from the search, i gather that the headers are slightly different from year to year and that '00+ are less reliable (+ 1/2 of the '99), but outside of searching around here, are there any other websites where i might be able to find the information?

i've got an '89XJ, 4.0, with 177k on it and the rod bearings are worn out (though it hasn't thrown a rod yet)

TIA for the help! :wave:

 

[raypla]

Do the same one he has it seems to be reliable w/xxxxxxx mi it seems to have worked 4 him, and lasted too

 

[lost1]

darn right the '00s are unreliable, mine's already cracked on me at 87K. Avoid them like the plague.

 

[collegeoffroad]

good to know about the '00...i'd thought it was going to be a decent one until i started reading up on things

any ideas about other years? Is the '89 a good base to work from, or should I be looking for a HO?

 

[Dr. Dyno]

Just about all of the 4.0 engines are pretty bulletproof but several 2000 models have suffered cracked heads so avoid those.

i've got an '89XJ, 4.0, with 177k on it and the rod bearings are worn out (though it hasn't thrown a rod yet)

If you're already hearing rod knock, don't delay in replacing the rod bearings. If you do, a rod will come out of the block one day and you'll have a much bigger repair bill on your hands.
You can replace the rod bearings fairly easily with the engine in the vehicle. Just drop the oil pan. While you're there replace the rear main seal, oil pump, and main bearings as well. Be sure to clean the inside of the oil pan thoroughly before you put it back on. There's probably 17 years worth of sludge caked on it and you don't want your nice shiny new oil pump pick-up screen getting clogged up with that nasty stuff. .

 

[75SV1]

You could use the bottom end (block) from any year and put your 89 head on it. Well at least to 01. Still, I'd probably do what Dino suggest and try and replace the bearings, oil pump and stuff. Yours is a Renix motor. Some bash them a bit. They had 13 less HP. Still, mine was OK for power. Renix one seem to get a bit better MGP. There is less header choices. The TB can be bored out. I think 59.5mm is the max on a Renix. Really comes down to how much power you want/need and how much money your can blow.
Tom

 

[Cjmartz2k]

I thought the 00+ headers were an improved design over the pre '00 headers. Mine was cracked when I bought it with only 39k on the clock, and it's a '98.

 

[lost1]

perhaps they were, but the warning's more against the engine head, not the exhaust headers. :wave:

 

[75SV1]

The 00+ headers are cast iron. They fit the ports of the newer, smaller exhaust port heads. From what I've seen, they won't or just barely cover the exhaust ports on the earlier heads. I have placed them on a '95 head.
Tom

 

[collegeoffroad]

Just about all of the 4.0 engines are pretty bulletproof but several 2000 models have suffered cracked heads so avoid those.



If you're already hearing rod knock, don't delay in replacing the rod bearings. If you do, a rod will come out of the block one day and you'll have a much bigger repair bill on your hands.
You can replace the rod bearings fairly easily with the engine in the vehicle. Just drop the oil pan. While you're there replace the rear main seal, oil pump, and main bearings as well. Be sure to clean the inside of the oil pan thoroughly before you put it back on. There's probably 17 years worth of sludge caked on it and you don't want your nice shiny new oil pump pick-up screen getting clogged up with that nasty stuff. .

any thoughts on rebuild vs. buying a remanufactured from advanced auto? I can get one for around 820 out here in VA, but I'm not sure how much it would cost for the rebuild...didn't know what was involved to look up!
:rattle:

 

[75SV1]

The 00+ headers are cast iron. They fit the ports of the newer, smaller exhaust port heads. From what I've seen, they won't or just barely cover the exhaust ports on the earlier heads. I have placed them on a '95 head.
Tom

I should say the cast iron ones. There might be factory tube 'header' manifolds.
Tom

 

[lost1]

any thoughts on rebuild vs. buying a remanufactured from advanced auto? I can get one for around 820 out here in VA, but I'm not sure how much it would cost for the rebuild...didn't know what was involved to look up!
:rattle:

Lucky...I paid 1800 for my reman, cheapest around here. Apparently these engines have been selling like crazy in the SW

 

[Dr. Dyno]

any thoughts on rebuild vs. buying a remanufactured from advanced auto? I can get one for around 820 out here in VA, but I'm not sure how much it would cost for the rebuild...didn't know what was involved to look up!
:rattle:

You might not need to go that far unless you've also got worn piston rings and the engine's burning oil. Otherwise just do the things I've already mentioned and they'll breathe new life into the engine. Hopefully it'll go several thousand miles before you'll need to touch it again, and you'll have only spent ~$200 in parts (oil pump, rod/main bearings, rear main seal, oil pan gasket).

 

[collegeoffroad]

unfortunately, i've got huge blowby problems (spits quite a bit of oil through the air filter), so I'm thinking it might be a good idea to just go with a reman. It's a bummer though, because it'd be nice to have the stroker, just more money than i probably need to spend right now.

at this point, i'd just be happy having my jeep back!

 

[Dr. Dyno]

You could buy a Titan Engines stroker for ~$1900 from e-bay. If you're interested, you could phone them and get more details.
OTOH, you could buy the reman for $1100 less and use the savings to rebuild your existing engine into a stroker later on as time and budget allow.

 

[75SV1]

Your blowby could be from the rings or it could be from a malfuntioning CCV system. Mine had about 135K on it and it puked about 1 quart in 100 miles. It was so bad, when I picked up some Jeep parts in Ohio, the guy appologized that I had to drive so far and blew up my engine. I did some fixes and the airfilter was clean for a few months till I blew my slave cylinder.
Tom

 

[collegeoffroad]

You could buy a Titan Engines stroker for ~$1900 from e-bay. If you're interested, you could phone them and get more details.
OTOH, you could buy the reman for $1100 less and use the savings to rebuild your existing engine into a stroker later on as time and budget allow.

that's a good idea right there...hadn't thought about it. Only question is whether they have a core charge (which, since it's advanced auto, I'm assuming they do). Depending on how much it is, it still might be worth it though.

thanks again for the advice! You guys have been lifesavers as always
:wave:

 

[zerf0]

I've recently developed a knock at idle in my '92 4.0. I have not checked the flexplate to torque converter bolts yet. If I do need to replace rod and main bearings, how do you install the main bearings on the block side with the motor still installed? Does the crank have to be dropped completely? Do you somehow slide the bearings around the crank like the top side of the rear main seal is installed?

 

[Dr. Dyno]

Sent you a PM.