co mixture effect timing??

[lagoon]

Previous post indicated that after changing the CO mixture to also check the ignition timing. Is this true? I don't see how the mixture could change the timing. Anybody know? 81'SC

[Jim T]

Changing the mixture can't affect the timing (the base timing on an SC is mechanically fixed by the distributor),

but I'd think that changing the timing can affect the mixture.

[schubee]

Originally posted by Jim T
but I'd think that changing the timing can affect the mixture.

I'm getting ready to smog my car and I adjusted my timing from 10 degrees advanced back to TDC. Would this richen or lean the mixture?

[lagoon]

John, your car should be 5 degrees BTDC with vacuum hoses disconnected. If you set it to TDC, your car will run terrible and may cause engine damage. 81'SC

[schubee]

Originally posted by lagoon
John, your car should be 5 degrees BTDC with vacuum hoses disconnected. If you set it to TDC, your car will run terrible and may cause engine damage. 81'SC

........what kind of engine damage? I'm not driving the car right now because I'm in Michigan. It doesn't seem to run terrible and I'm getting better gas mileage. I've been driving around with it at TDC for only 3 days. Hopefully it hasn't caused anything severe.

[schubee]

>> bump <<

........anyone?

[lagoon]

John, all I know is when my timing was set to TDC by mistake, It ran terrible. Didn't think I would make it home. 81'SC

[nhromyak]

I believe when you retard the timing, you will get less HP, but better low-end torque (to a degree).

I believe You will get a better combustion burn at the lower RPMs (better mileage), only if your CO is set for this newer timing. Your higher RPM power (HP) will suffer.

There are many things that will affect your CO settings in the low, mid, and high end.

Good luck.

[RoninLB]

I'm w/Nick on this one...to my understanding, the best way to plot an advance curve is on a dyno...a comprise due to variables is a good shot...that comprise takes your driving style and engine use into consideration and of course engine set up...Ron