Spark Timing

[Chris Hill]

I've been reading some engine books recently and it got me thinking about spark timing and different engine combinations in S/SS. In general, the better the combustion chamber and intake quality, the less spark timing is nessary. Would folks be willing to share what timing settings work best for you with your engine combo and fuel?

I'll start. Our 4.3 chevy v6 liked 40* with c10 or c11 fuel in stock eliminator.

[Billy Nees]

Chris, excellent subject but, I think that it is a subject that becomes too "singular" in scope. If we can agree that, after a certain point, timing becomes a "crutch" then you will know what I am meaning by it being too "singular".
Most of the "stuff" that I'm playing with right now seems to naturally want about 33 or 34 degrees total. That being said, this past year, I took one of my motors and installed it in a car weighing almost 400 lbs. more than what it is usually in and the same motor/trans/converter (more gear) wanted 6 degrees more timing to "peak" its ET. I think that you're truck is a good example of that because (IMHO) I don't believe that you're motor (using C-11 especially) should need 40 degrees of timing. Please reply as this is a subject that really does interest me.

[Ed Wright]

That's a lot of timing, particularly for an iron head engine.

[art leong]

Originally Posted by Billy Nees

Chris, excellent subject but, I think that it is a subject that becomes too "singular" in scope. If we can agree that, after a certain point, timing becomes a "crutch" then you will know what I am meaning by it being too "singular".
Most of the "stuff" that I'm playing with right now seems to naturally want about 33 or 34 degrees total. That being said, this past year, I took one of my motors and installed it in a car weighing almost 400 lbs. more than what it is usually in and the same motor/trans/converter (more gear) wanted 6 degrees more timing to "peak" its ET. I think that you're truck is a good example of that because (IMHO) I don't believe that you're motor (using C-11 especially) should need 40 degrees of timing. Please reply as this is a subject that really does interest me.

Billy on the old Hemi we ran 40 degrees most of the time. While all the superstockers ran 36. We also ran faster with "SoCal" Prostock Orange than the lower octane stuff.

[Billy Nees]

Art, generally, the higher the octane the fuel, the slower the burn rate, the reason to need more timing.

[ron mattson]

Octane definately matters, as does geography, the timing you would use at the coast
in sea level or better air is going to be different than what you would use in the minnesota
swamp bp of 28.50 or denvers 5,000 plus ft elevation

[art leong]

Originally Posted by Billy Nees

Art, generally, the higher the octane the fuel, the slower the burn rate, the reason to need more timing.

Yes Billy we found that out with a lot of A-B-A testing The guys at Mopar couldn't believe it, They though our balancer was degreed wrong, or the TDC mark was wrong. but everything was right. They even brought out their own timing light.
We had a lot more cranking pressure that the SS motors due to the big cams they ran. It wanted the timing and the fuel.
I believe I told you how we corrected our timing when we were at a race? Water pressure!!!!! Worked like a charm.

[art leong]

Originally Posted by ron mattson

Octane definately matters, as does geography, the timing you would use at the coast
in sea level or better air is going to be different than what you would use in the minnesota
swamp da of 28.50 or denvers 5,000 plus ft elevation

When we ran Denver we just bumped the timing 4 degrees. And were able to run the index. Never touched the carbs

[Chris Hill]

Art, what did the turbo cars like for timing?

[art leong]

Originally Posted by Chris Hill

Art, what did the turbo cars like for timing?

I used stock ecu's so timing was controlled by the computer. I would set the intial (distributor) to 18 or 20 degrees