plastic timing cover?

[burwoodk5]

Went to napa and they gave me a plastic timing cover for my 87 350, is this correct or should i send it back? Its also missing 2 bolt holes, it lines up fine though. thanks

 

[dyeager535]

Sounds to me like they gave you a Vortec cover...does it have the spot or a plug for the crank position sensor?

It probably won't hurt anything, perhaps this is the aftermarket saving money...

 

[burwoodk5]

It does have a hole for the crank position sensor, but its blocked off with a cap. It seems leak prone. Parts stores around here only carry chrome and plastic, hmmmm

 

[Busted Knuckles]

If you don't have a vortec specific block, you'll need to seal a gasket to the block, then seal that plastic cover to it. They changed the boss on the front of the block when they went to the plastic cover and it barely touches in a couple of spots. Been there, done that. Either that or you can run a conventional timing cover, only the back of the pan changed when they went to a 1-piece rear main seal.

 

[dyeager535]

Hmm, if the blocks changed in the front, perhaps the aftermarket plastic cover was changed to work with both?

Obviously there is no issue with the plastic cover when used correctly, GM did it.

 

[Busted Knuckles]

They came out with the plastic timing cover in '96 with Vortec engines, they needed the spot for a crank sensor. That's the same year they changed the blocks. If you get a chance to look at two of 'em side-by-side, the difference is apparent. Hold the new timing cover up to the block with no sealant, etc. and you'll see where the "O" ring barely touches in a couple of spots.
I'd take it back and get the correct one, make sure the NAPA guy knows you're working on a pre-96 block.