request a lesson on engine timing Options

[type47]

I'd like to know on what parameters does the timing of an engine depend: induction? cam? I am resurrecting a 2L with a carb cam and installing a CIS basic system. We started the engine at the ECC in Oct and am progressing very slowly. I think the engine has an 009 dizzy (engine is still at ECC site so can't check now); at least it has a non-vacuum advance dizzy. I have a 2L D-Jet dizzy ready to install and that will probably be one of the next steps. When we started the engine, it did not sound smooth running but it started and that was the intent at the time,

http://www.youtube.com/watch?v=gRLyDnp7G_0#t=15

but there could be other things that caused that. My question is really to what specs do I time the engine; 27 degrees @ 3500 rpm like a D-Jet?

[r_towle]

Let's see.
The 009 advance curve is just plain wrong for a type 4 motor, so you will end up making a compromise of the transition advance at some point in the curve.

Overall timing, and total advance is very closely related to the camshaft (valve timing) so if you have a different profile on the camshaft from stock, your ignition timing will be different.
You may want to ask the camshaft grinder what they suggest.

Overall total advance can also be affected by compression ratio.
Higher CR creates a higher possibility of detonation.
That can be offset by a different camshaft, higher lift, more overlap etc etc...

So, ignition timing is best done (custom) on a dyno or with lots of data acquisition on the open road.

Rich