Well this is tough one to answer, because it depends on the honesty of the mechanic.
An engine rebuilder would normally measure the block deck height and cylinder head deck surface to make sure there wouldn't be any problems. But if they skipped this procedure, it's possible it was milled too much and the valve head slapped a piston and punched a whole through it.
As for the car not idling on it's own: Does it drive well at higher rpms? If so, then there's no whole in your piston or broken valve. If it won't, then it's possible he's telling you the truth.
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Tuesday, November 23rd, 2010 AT 11:33 AM