help diagnose
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Teching In
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help diagnose So my car sat for a week and a half and then wouldn't start. when the heads were taken off it had oil on top of the number 2 piston. At top dead center the piston to bore clearance is .0037. The heads and head gasket were checked at a machine shop and said they were fine. So how does oil get on top of the piston while it is sitting when the heads aren't the cause? Just seems that oil wouldnt rise while not running. The shop just acted like they had no idea.
Only way I know that oil can get on top of a piston would be a broken piston and or rings, or a bad valve seal letting oil leak by and travel down the valve stem around the valve and then into the chamber.
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That is what we thought. The piston isnt cracked, and the machine shop said they pressure tested the heads and they are good. So that leaves the rings. But the car had been sitting, so why would oil travel against gravity up above the piston. And even then, while it was sitting the oil should of drained back into the bottom since it wasn't running. Makes me think that one of the valve seals is bad and the machine shop is wrong.
How much oil on top of the piston we talkin about,,A light film or a puddle, if you have stock pistons they are flat tops and shouldnt hold any oil,,However if the top of the piston was submerged in oil,,that would lead me to say that the rings are good,cause they are stopping the oil from running down, I also have a few questions, are they working on this engine in the car,,If they are then its impossible for them to "check your piston and rings" you would have to remove it from the block. And if its still in the block I dont see how in the world they could possibly give you the measurement of .0037 piston to wall clearance.
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turns out they lied to me for the last 2 weeks. It was a cracked head that leaked antifreeze on top of piston and caused it to hydrolock. The piston is still in the cylinder and the motor is still in the car and they said at TDC they checked the piston to bore clearance to be .037. So im wondering if maybe the motor is fine and i just need to replace the heads now instead of both the heads and block.
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Thread Starter
Teching In
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Well i got the car home and was just looking at the cylinder. I don't have much experience with this stuff but you can still see the cross hatching on the cylinder wall. I will try to take some pictures of the cylinder and see what you guys think.
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