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Old 01-29-2013, 10:42 AM
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cobalt327 cobalt327 is offline
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Originally Posted by zildjian4life218 View Post
I wonder if its worth it to see if my machinist has a timing chain for a vortec that I could mock up real quick to check. I have only seen older blocks, vortec blocks and my block and I would definitely agree that mine looks like the vortec one. Idk what GM did differently between the flat tappet, the pre vortec rollers and then the vortec rollers.

Thanks for the input guys. Sorry took me so long to get back to you Ive been swamped with school and work.
Couldn't hurt to try a Vortec-specific timing set or at least the cam gear to see if there's a difference.

To help w/the diagnosis, the timing set currently being used is SUM-G6601. Application is '85-'99. It says "For factory roller camshaft Gen 1 motors, except 1996 and later Vortec. Will not fit behind stock plastic timing covers."

The timing set that was mentioned as a possible replacement for the Summit timing set is Cloyes p/n 9-3145. Application is '85-'99. Says "For factory roller camshaft motors. Will not fit behind stock plastic timing covers."

The camshaft is a Howards OE roller.

I have heard of double row cam gears requiring the block to be clearanced, and it's common knowledge the plastic timing covers are a problem. I've also heard the steel cover may need to be replaced or use doubled gaskets for clearance, although I've not had that problem on any I've dealt with. But if the retainer plate is being pinched between the cam gear and the step on the nose of the cam, something's just not right (obviously). It seems like measuring the length of the cam nose step, the depth of the bore in the back of the cam gear where the cam sits, and the thickness of the retainer plate should show what's wrong.

Last edited by cobalt327; 01-29-2013 at 10:49 AM.
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