What determines the engine timing?
 

I have a 2.2 litre 911 T engine with e cams.

My questions are:
(1) What determines the timing value for an engine? Is it the cam profile? (wow - do I sound like a newbie?)
(2) What would the proper timing be for my engine?

Thanks in advance

Look up the factory spec.

How much timing a motor will take depends on a lot of variables that together must be tested to see what is effective.

Compression, position & head profile, cam profile and timing, operating temperature... all effect ignition timing.

There is also a ignition timing curve as the effective timing changes with load and rpm.

On an older cars there are weights, springs and vacuum canister/s in/on the distribuitor that control the timing curve.

It is the cam profile. That is my guess. The timing recommendations for the same engine are different with different cams.

For example, my stock SC engine has a timing of (I think) 1.1mm for stock cams, but 1.26 for my 964 cams.

More aggressive cams lower the effective compression ratio.

A lower compression ratio slows the burn rate and requires more advance.

Higher rpms require more advance.

If you have the original Pistons and compression I would start with the T specs and distribuitor. You could fine tune it on a dyno from there.