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visualsmoke 10-01-2011 02:49 PM

zz502 timing chain and sprockets question
Regarding the single roller timing chain and sprockets that come on a crate engine zz502 (timing chain and sprockets: GM part number 12371053), are these machined in a 'retarded' configuration? The literature I got with my new Edelbrock cam says this is the case.

zipper06 10-01-2011 07:58 PM

I think most of the GM motors come with the 10 degree retard on the cam since the use of ECM's and the knock sensers. i can remember back in the 80's the trick for a little more performance was to degree the cam in to "0" for more bottom end. But i would still pull the timing cover and check the gear. I had a friend who had a ZZ502 in his truck, it lasted about 40,000 miles and shelled the gear. It had plastic teeth on the cam gear for less noise, i don't know if they still use them, but i know they have been used since the 1960's, just a precausion.


visualsmoke 10-02-2011 03:01 PM

Pix of cam sprocket
The gears are not plastic. They look to be quite heavy duty. In fact, the chain is bigger than the drive chain on my motorcycle. Looks to be plenty strong for my needs, so, provided they are not machined 'retarded', I'd like to reuse them.
The pix below can be clicked for a super-sized view.

zipper06 10-02-2011 07:25 PM

Then the only way you can see if the cam in installed at 10 degrees retarded, is to get the specs for the cam and put a degree wheel on the engine. Doesn't take but a couple hours, but then you'll know for sure.



visualsmoke 10-03-2011 02:10 AM

Thanks for the tips. I will mock it up with the degree wheel as you suggest and see what happens. I post and let you know what I find.

ganther5000 10-15-2021 03:53 PM

let us know I'm interested on how this is gonna turn out

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