Engine Balnce

Internally, unless it is a very early production 89. The first SCs had a cast crank, which was a 28oz externally balanced engine. Shortly into production, they switched to the forged crank, which is internally balanced, and was used on all late 89 through 95 SCs.
 
Thanks guys. I have a bhj to install on my 94. When i removed the crank pulley the balance weights were loose and fell out. It will help knowing , to get it rebalanced.
 
Any idea the build dates, VIN #s for the '89 change over? Or is there an easy way to ID the internal vs early external balance? I have several '89s, and several "extra" motors :cool: and understand the earlies are a known weak crank. So much so my understanding is not many out lasted the warranty, and fewer still r probably in service, but I'd like to know if any ended up in my pile BEFORE I put any time $$$ into one

Thanks

Adam
 
They did have a different VIN digit for the motor, but I don't remember what it was. A forged crank car will have an "R" as the 8th digit of the VIN. If it has any digit other than "R" in the 8th spot, that means it came out of the factory with a cast crank engine.
 
I would think the dampers would look different. The externally balanced damper would have a counter weight on it, or so i would think. Or if the engines are out yank the pan and look at the parting line on the crank. Thin lin cast, thick line forged i believe.
 
Well the damper, accessory drive, and jackshaft are all within 7/10 of 1gram of being perfectly nuetral balance. A dollar bill weighs 1 gram.
 
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