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87 Jeep Cherokee Cheif 4.0

Thats not good looking..... Not sure what would cause that. I know what needs to be done now, but i dont know what caused it unless some debris got into there.
 
WOW. How's the compression on that one?
Was there debris in that cyl?

Could that be caused by detonation or come from the factory that way?
May be overheated?

How do the cylender walls look?
 
i traded my s10 for it and on the way home it overheated realy bad and melted the pvc valve on the top of the valve cover and shot oil out the top there and died. when i got it home it started and ran but it ran like shit i think the compression was bad cause it had a blown head gasket. and the only debree in the cylinder was from when i pulled the head off
 
First of all, you have a super rare vehicle... fix it up right and cherish it!

If you're gonna repair one piston, at least pull the others and make sure they're in shape, then re ring them if they are good. Hone the cylinders too. Yeah, a full rebuild would be best...

You should post pics of the rest of the vehicle!
 
My 90 did the same thing, pistons #3 and 4 completely shot at 140k. I went ahead and rebuilt the engine getting it bored out 40 over and decking the block/milling the head. It runs like a champ now 20k later. This XJ was in my family since day one and it always had a knock(piston slap) that the dealer disregarded about 30 times while in warranty. I could be wrong but I think a leaky head gasket or a fuel delivery issue led to the piston melt down, the piston slap was just poor workmanship from the factory. The pistons were not sized to the bore very well.

Not sure what to offer you for a solution other than spending money you don't have right now.

It may be easier/cheaper to pick up another engine in the junk yard.
 
for a piston to chip like that

stuck fuel injector "washed out" cylinder
misfiring spark plug
major ping or detonation
out of spec bore, and severe piston slap


I do see scuffing in the bore. That might hone out. But at that mileage, repairing just one cylinder is a gamble. A lot of tear-down for a limited repair.
 
well my uncle is a mechanic. hes been doin it for lik 30 somthing years so hes gonna look at it for me and see if it can just be done with the one piston if not i found another engine up here for 200 but not sure on the running condition of that one
 
Captainhswh said:
well my uncle is a mechanic. hes been doin it for lik 30 somthing years so hes gonna look at it for me and see if it can just be done with the one piston if not i found another engine up here for 200 but not sure on the running condition of that one
Click to expand...

Look in to the other engine, if the person doesn't know, ask if you can pull the head and pan to look! If it looks to be in good shape (not to much carbon on the cylinders, no metal shavings in the pan), clean everything up real nice and replace the head gasket, then throw it in.

Next, slowly save money to rebuild the old engine right, so you'll have something for the long run, and to add some piece of mind.

I was planning the same as what I just stated, and I have very little money, but my $180 replacement engine has been rebuilt recently so we're just gonna do seals and rings and probably sell the old one if we can...
 
Looks familiar. Bought it this way but I believe it lost water & detonated it's way to this (same piston in both pics.) It ran but really rough. The crack below is between 3&4 and last pic is #6.

If you don't have the $ and the compression is up on the others it's probably ok to replace just the low compression pistons although if you can swing it do all 6.

326716295_ece97c76ab.jpg


326716292_caf8277a46.jpg


Sure you don't have cracks like these:

274259071_6bc1ea51d8.jpg


471891606_b49360c743.jpg
 
Last edited:
X2^^, it would be worth the money to get the head checked out and magnfluxed. Cost is $25 for the local shops to check a head around here.
 
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