Initial timing setting for first fire?
 

Good morning,

I'm getting very close to firing my fresh '79 930/64 motor (USA) with SC cams. Overlap setting 1.4 mm on the cams. (Euro CIS, euro heat exchangers, 36mm intake runners, stock Mahle pistons with Carrillo rods, I have the early vacuum advance only distributor) big 965 intercooler, K27/7200, Tial WG

Because of the SC cam upgrade I'm curious as to the best static setting for ignition timing to get it to fire and thought I'd get peolpe from the groups opinion.

Here is a chart of different ignition timing settings for turbo and 911 SC. Right now I simply set it at 5 degrees BTDC. Thanks
Matt


http://forums.pelicanparts.com/uploa...1616849546.jpg
http://forums.pelicanparts.com/uploa...1616849546.jpg
http://forums.pelicanparts.com/uploa...1616849546.jpg

I do not think cam choice really affects initial ignition timing, so I would simply go with what you are planning to do.

I may be missing something, but valves are closed when ignition takes place, and I do not believe these cams make a bit of difference from the perspective of starting the engine. The cams just affect when air and fuel are able to enter and exit the cylinder on the intake and exhaust strokes.

Congrats on the new engine install! Hooray! This is going to be fun :)
If you dyno it, post the results in the dyno thread.

Thanks s5uewf

Then I should probably go 10 degrees +/-2 ATDC.

This is Bandit the turbo S/T

Matthttp://forums.pelicanparts.com/uploa...1616899599.jpg
http://forums.pelicanparts.com/uploa...1616899599.jpg

That looks like a total blast! Beautiful!
I think removing side mirrors or having smaller side mirrors really do make the car's shape stand out that much more.

Good luck with the install and tuning!

Also, you may find this thread interesting and useful:

http://forums.pelicanparts.com/911-930-turbo-super-charging-forum/500986-ultimate-930-distributor-advance-retard-timing-turbo-lag-msd-mod-thread.html?highlight=cis+timing+thread

Thank you!

FWIW I idle at 10 BTDC I think the initial cranking spark is at TDC moving to 10 BTDC after 450 rpm.

Thank you. I'm set at 5 ATDC. If this is the case this means I should probably set initial spark at 15 degrees ATDC to be at around 5 ATDC at 1000 rpm with vacuum advance connected.

I'd suggest locking the distributor and installing the programable MSD with boost retard while it's apart.
Having a proper timing curve makes your other mods work so much better.

Thanks great advice but not right now as my wife has been really understanding and patient ($) and I don't want to press my luck.

I've never owned a 930 but of this vintage I'm guessing the timing settings are more for emissions and will have the motor run warmer.

I have initial setting at -15 ATDC but will advance this back to -5.

I won't be revving it too high for a while anyway.

I will use a light on it once it's safe to rev above 4k.

Matt