Topic: 4 cyl Rebuild ... Options?

[RNandKT]

OK I have a some questions for everyone. Just today I came across a TJ with a motor going bad (still runs actually but I think it cracked a head since it dropped compression between cylinders 2 and 3), and it looks like he is going to take my offer.

Anyway this would be a second TJ for me, and I don't need to drive it as it would be a spare car (actually specifically the wife's). Anyway rather than just swapping in a used motor like I did in mine, I was thinking of doing a quick rebuild on it instead. The rebuild kits are cheap, but if I am going to do that, I was thinking throwing in something a little hotter might be nice.

So anyone done some mild internal work, and where did you source your stuff and most importantly how much did it cost? If I could pick up a nice Cam or something without spending too much more it would be nice. I was planning on going .030 over anyway, but other than those things I think it would surpass my planned budget (I am aware of 505's stroker kit, but I don't think I can spend that much).

Anyway let me know what you guys have done, how much it cost, and was it worth it ..... If it's just not worth it I will do a normal rebuild and save the money for gears. Let me know your thoughts ... Thanks in advance ...

[Rio_Grande]

I can't speak for the 2.5 specifically, I grew up on a farm and we didn't replace squat. We would overhaul as opposed to rebuilding, strip it down clean thoroughly. Instead of boring, we cut the ridge out with a ridge reamer, ran a bore tool through the cylinders and restored the cross hash and then replaced the rings. Sometimes we ordered touch bigger and filed the gap to make them fit. Replace the crank, cam bearings, lifter unledd they were solid and had the head reworked. The appropriate bearings in the bottom end and back together. We have done this to farm trucks that the engines continued to run long after the frames were junk, some came out and went into other equipment.

Something to think about and it takes out the cost of new pistons, machine work and time down.

[grumpygy]

Cracked head, Cracked Block or just blown head gasket.  Would be nice to know which one.

[RNandKT]

Yeah reman'ing the motor is cheapest, the standard reman kit is only like $150 (not including any machine work of course), but if it only cost another couple hundred to get a few more ponies ....

I wont know whats wrong with it for sure until I pull it ... or at least till I pick the Jeep up tomorrow ....

[Tr00b]

Common for head gaskets to blow between two cylinders. Replaced one myself on my ranger which was a bitch because its ohc. If its just a head gasket you should be able to just have the head refreshed and be good. My ranger sandblasted the valve stems on the exhaust ports with coolant and chunks of detonated spark plugs. Because the jeep is pushrod the head should come off in an afternoon.

[VA_YJ]

I agree with Tr00b - the most likely scenario is that the head gasket is blown between cylinders 2 and 3.  Pull the head and then you'll know :-)

[RNandKT]

Yeah after hearing it, thats my thoughts. I went ahead and bought it and pulled it into the garage. I will see about pulling the head this weekend.

[Tr00b]

That sounds like fun. Good luck with it, hope you can turn it around for some good money maybe.

[RNandKT]

I am planning on keeping it. I have 4 kids, so want to fix this one for my wife so we can start going on some family trail rides.

[Tr00b]

Sounds awesome. And fun.

Post pics of the teardown!

[RNandKT]

Will do ...

[RNandKT]

Yep turned out to be a bad head gasket. Never seen a blown head gasket where it actually was missing part of the gasket. Anyway it is back together now and runs great. Lift kit next weekend ... ;-) I will upload the pics tomorrow night.

[sharpxmen]

it can "burn" between cylinders and sometimes the cause is if you run lean so keep an eye out for that (in case yours was missing a piece there).

[RNandKT]

Yeah it was missing a piece between the cylinders. Did not cause any damage to the block or head though (the guy parked it the day it happened). I went ahead and had the head shaved and replaced the spark plugs, thermostat and lifters while I was in there. If I can get the replacement ford injector from the guy on ebay I will replace those too (may have to buy another one).

[RNandKT]

So Cost:

Jeep with "bad engine" and 160 K miles $3000

Bad head gasket:
New head gasket - $12
New Lifters - $45 (5.29 each)
New Thermostat - $9
New Plugs - $13
Misc other gaskets (valve cover etc) - $17
Head machine work - $52'

Now it purs like a kitten. In fact it sounds quieter than my TJ (and when I bought my Jeep it had a rod knock and I swapped out the motor from one with only 77K miles, so the fact that it runs better is pretty sweet, you never know how long those lifters will stay quiet though).

And we sold the awful bushwacker flares off of it and put the stock TJ flares back on so that netted us some profit. I also scored a deal on some wheels and tires and lift springs. So next weekends project is 2.5" lift and 31's. Adding pictures of the tear down in the next post.