I have a 1997 S-10 blazer, we rebuilt the motor after a spun bearing toasted the original. (bought the blazer that way $250) The heads were rebuilt, and a donor block machined. My problem is: The motor has eaten two flexplates and a distributor gear. If the flexplate is aligned properly, the distributor is getting eaten by the cam, and is miss-firing. When you replace the distributor the flexplate gets chewed up. Are there different number of teeth on flexplates for different year models of 4.3? Or could the timing gears be miss-alined?

 

What year was the donor engine?

 

I believe it was the same year, or one year younger (1996)

 

Typically if the flexplate is getting eaten there is an alignment issue witht he tranny or the tranny may have a bent input or broken pump. Next time you replace teh flexplate make sure the tranny pump is one piece. Also make sure you are bolting it down tight, and using the tranny cross brace, check your motor mounts too. Is this a new torque converter, or are you using hte old one? Could the old one have gotten bent when the bearing went?

When you rebuilt it did you put in teh retainers. Devices to push the cam and crank back in the block? I am drawing a blank on the proper term, however they hold the cam/crank from sliding around front to back within the block.

 

I do remember putting in a cam spacer or plate. But I do not remember any kind of "spring" type pusher on the cam or the crank. Do you know of a schematic of the 4.3 that might show these parts? Thanks for the time/info.

 

The crank is centered via the thrust bearings. If there is too much end play in the crank... I cannot remember what you do. But there should have been a retainer plate behind the cam drive sprocket to hold that into the block.

It definitely sounds like there is something amiss in your engine... Although at this point in time, I just cannot think what would be common between these two events.

 

The retainer plate was replaced on the cam. but i don't remember any kind of spacer that would have actively pushed on the cam to keep it from walking when we tore the motor down.

 

If the teeth are getting chewed up on the flexplate wouldn't that be a starter problem? the distributor gear is a different problem unrelated.

 

Yes that would be correct.
there are a couple reasons the flexplate is getting chewed up by the starter.
1) Misalignment between engine tranny.
2) broken flexplate.
3) Starter loose and flopping around.