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Old 10-29-2003, 02:01 AM   #2
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Re: bad vibration 4G63 engine

Originally Posted by zyman
help, iv'e got bad engine vibration @ 1800 - 2500 RPM
the cam belt has been changed afew months ago.
i got so p******D off i dropped another engine in.
guess what? same problem. could it be transmission?
any ideas?.
The 4G63 has two timing belts, the main one drivn off the crank turns the oil pump/balance shaft, and the cams in the head. The second belt is also driven off the crank sprocket and it turns another balance shaft. Your vibration could be caused by one of the following two things. 1. The balance shaft belt snapped, and the the engine is vibrating because the other balance shaft is still spinning, without the other shaft to counteract the motion of the shaft. 2. The oil pump balance shaft is out of phase. It's possible to align all timing marks correctly, but still have the oil pump shaft be out of phase. the only way to make sure the pump is aligned correctly before installing the main timing belt is to remove a plug and verify it's position. there is a very helpful guide to removing and installing a timing belt in a 4G63 engine at in the "engine" section. Hope this helps.
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