Cam Degreeing

[upsidedown]

I need some info on degreeing a cam. I assume that when a manufacturer specs a degree point to install the cam that this would be where it should be when the engine is running. So on a sbc turning 8000 rpm using a belt drive should I advance the cam 2 or 3 degrees from the specs to allow for belt stretch so when it is running it is closer to the correct timing. Thanks.

[user-23911]

Belt stretch?
That's another can of worms.


The best way is to measure as much as you can.
IO, IC, EO, EC. at working lash.
Then lift versus degrees of crank.
It takes hours.


Once you've done that a few times, you won't need to ask and you'll know who's telling porkies.

[upsidedown]

Yes thanks I have done all that sort of thing before but not on an engine with a belt drive. As this is a friends engine and I have limited time to check as he needs to get the engine back together asap I'm hoping I can get some info from someone that already has it?

So if BigJoe, CamKing, WolfPlace or anyone else that feels eminently qualified to answer could reply then I'm all ears.

[williamsmotowerx]

What is this engine used for?

Do you have sufficient PV clearance?

Just run slightly adv if you want bottom end, more on ret side if it's top end. Don't even worry what belt is doing.

It's all about PV and intended use if you don't have time to check cam timing while it's running

[CamKing]

I really doubt your belt is stretching 2-3 degrees.

[Keith Morganstein]

Gilmer belts (toothed timing belts) of modern manufacture have almost no stretch at all.

[user-23911]

Gilmer belts (toothed timing belts) of modern manufacture have almost no stretch at all.

Yes, that's why cam belts for OHC engines have auto tensioners.
The ricers think that the belts stretch but they don't.
The engine grows as it gets hot so the belt tightens up.

[bigjoe1]

I have found that in the engines I build, four degrees advance from straight up has always worked out very well. If you have the ability to test on an engine dyno, you can see what is best for your application




JOE SHERMAN RACING