Crank Pulley ID

Giro

Registered User
In the final stages of my engine swap, I noticed the crank pulleys in my old and new engines are completely different. Im curious if there simply is a.difference in pulleys amongst different years, or if I have an aftermarket performance pulley. The old one has a smaller outer side and bigger inner side, and off of a 1991 engine. The new engine, 1990, has a larger outer side, and smaller inner side.
 

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Ok, thanks for the info. I was going to transfer it anyway because the water pump pulley wouldnt go on with the larger crank pulley.
 
That means you also have the underdrive water pump pulley, and possibly the alternator pulley as well. On my car, I only run the underdrive crank pulley with factory other pulleys, but either way will work.
 
Makes sense, I think I do have an underdrive pulley in the alternator too, I always thought the alternator pulley was oddly close to the upper IC tube, about half an inch or less.
 
Makes sense, I think I do have an underdrive pulley in the alternator too, I always thought the alternator pulley was oddly close to the upper IC tube, about half an inch or less.

Alt pulley for the underdrive set is right around 3" diameter (top of ribs) and the stock alt pulley is around 1-7/8" dia. I agree with transferring all pulleys to the new motor. Note: The crank pulley bolt holes are not symmetrical, one hole is slightly off and the crank pulley will only bolt to the balancer in one position, so don't try to force it just keep rotating pulley until all 4 holes line up.

David
 
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