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Discussion Starter · #1 ·
I have a 1990 with a 2.5, took it on a trade with out hearing it run. Even with a few problems I still made out on the deal. When I start it, it runes fine, but it knocks, sounds like in the bottom end so I pulled the oil pan and put a set of rod and main bearings in it. The mains are .010 under and the rods are .030 under. Also put a timing set and tensioner in it. Airlock sounds the same, like a diesel. Any suggestions on where I should be looking next?
 

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How many miles on the engine?

Sounds like you could be dealing with piston slap. If that is the case, the only remedies are to bore and rebuild the bottom end, buy a used engine, or buy a remanufactured long block.
I say long block because if the bores are worn past the limit, then most likely the valve guides in the heads are worn too.
 

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Discussion Starter · #3 ·
Realy couldn't say on the mileage cause there hasn't been a speedo cable in it since I've owned it but the odometer says 147,000, but who knows what it realy is. If it is piston slap what is the worst that will happen if I keep running it. It's my only vehicle and I drive it prolly close to 100 miles a day.
 

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It's hard to say what will happen. My SBC 350 ran for over 40,000 miles with some piston slap. The wife's Grand Caravan ran for about 200 miles before a piston exploded destroying the engine.

Some engines are ok with piston slap, some aren't.

I had a thought to help you find the source of the knock. Buy yourself a mechanic's stethoscope. It will help you zone in on the source of the knock. If you cannot find one, get a piece of 1/2" pipe about 2 or 3 feet long and put one end on the engine block and hold the other close to your ear, The sound will transmit up the pipe. When I can't find my stethoscope, I use the pipe method with a set of ear muffs with one end of the pipe against the muffs. Sounds weird but it works.
 

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Mine has a bad wrist pin and makes a tapping sound, has been for awhile now....maybe this summer I will tear it down...
 
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