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2.5 Rod an Main Bearing???


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I have a 86 Comanche 2.5L auto 4x4. I went to go to the store the other day, an on the way home my oil preasure droped to 0 psi. So I shut it off an had a buddy drag me home with a Chain. I pulled the oil pan off an there was about a 1.5 inch pile of sludge in the bottom. I pulled 1 main bearing an 1 rod bearing. The main looked ok but the top rod bearing was down to the brass looking material. The rod bearings are standard, but the main bearing is .001 undersize. I have called every parts an engine supplier I know of an no one has a .001 undersize. Has any one here ever seen this before? Should I just get a standard main set an plastigauge it an make sure my clearance is ok, or do I pull the engine an crank an have the crank turned 10.10? I live in a apartment complex with no garage, so the easiest way the better. Thanks for any info you guys can give me.

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There should be a letter code on the passenger side of the block, near the distributor, that will confirm the bearing size. The factory did use bearings that were .001 under, and as far as I know the dealer is the only source for them.

 

On an old engine you could probably get away with running standard bearings. Gotta be tighter than the ones that were all worn away.

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Petermontie the oil preassure drop I'm sure was due to all the sludge, changed the filter an oil when I got the truck about a week prior to the preassure drop.

Ping pong the engine is still in the truck I don't think I can get the crank out unless i pull the engine which I can't do where I live.

Eagle I can see the numbers your refering to but will a jeep dealer have AMC parts? I'm going to try an put the standard bearings in tomarrow night, plastigauge it an see what the clearance is.

Thanks for the info an advice guys I'll let you know how it turns out.

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Oh cool. I didn't know if it was the same engine used. I thought the newer engines were Diamler Chrysler. An the old ones were AMC. I'll give the local Jeep Dealer a call tomarrow an see if they can get the bearings. I'll try the standard one's I got first though. This is my 1st jeep with a 4 popper. The last jeep I had was the 2.8L Piece of Crap. I'd like 4.0 swap this one but the funds an lack of a garage won't allow me to at this time. Thanks for all your help. :D

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changed the filter an oil when I got the truck about a week prior to the preassure drop.

 

Mine was fine for like 3 days and then the pressure just dropped off the gauge while on my way to a wheeling trip. It would partially come back if I revved the engine, so if yours doesn't show anything at all, then it might not be that. I mention this because a filter is real cheap and I changed a whole lot of things before I learned it might be the filter.

Jeep on!

--Pete

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I'm going to change the filter an oil after I get the bearings back in tomorrow. I'll check the old filter see if I can see anything. My oil preasure dropped to 0 an I shut it off, I started it about an hour after it happened when I had the manual gauge hooked up to make sure it wasn't a bad sending unit or factory gauge. It had about 30psi for about 30 seconds an dropped to 0 reved it up once an the preasure stayed at 0. I'll definatey keep you guys posted. Thank you for the advice, i'm all ears an try anything once or twice. Pending it doesn't hurt to bad the first try. :lol:

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Alright guys here's what I did. I installed New Rods an Main bearings, oil pump an oil pan gasket. I unplugged the coil an fuel pump, cranked the engine until I got about 60 psi of oil preassure. Hooked the coil an fuel pump back up an started it up. I now have 60 psi at a idle an it goes up around 75 psi when i rev the engine up. No knocks, banging, Clanging. Purring like a kitten an quiet as a mouse. Thanks for all the help an advice guys.

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