Timing way off

[911Brian]

Today I checked the timing of my 80 SC. I took off the vac lines and plugged them, then checked the timing @ idle. It was way to the right of 5 deg..... So, I set it to 5 deg. Anyway, took it for a test drive and it drove just fine. What neg effects would running the engine at that timing be?

Thanks!

[911Brian]

Anybody?

[jmohn]

Originally posted by 911Brian
Today I checked the timing of my 80 SC. I took off the vac lines and plugged them, then checked the timing @ idle. It was way to the right of 5 deg..... So, I set it to 5 deg. Anyway, took it for a test drive and it drove just fine. What neg effects would running the engine at that timing be?

Thanks!

Almost certainly ... Nothing. I don't know (without looking it up) what the base timing is for an '80 SC, but, if the mark was to the right, I think you were over-advanced 5 deg. on base timing. Someone may have set it what way on purpose to get a little more advance at higher RPM's (at little more power). I don't think 5 deg. additional advance would cause any negative affects, even if you use regular gas, unless you "lug" the engine a lot (typically, if you run very much above the recommended base timing, you should use higher octane gasoline).

Jerry M
'78 SC

[911Brian]

hmmmmm... I wonder if I should set it back then. The car ran great with the previous and current settings. I guess I will leave it for now and check the total advance when I get a chance.

[Superman]

When JW times my engine, he sets timing at 35 degrees total advance. That results in an idle setting (hoses disconnected and plugged) of about 12 degrees BTDC, rather than 5 degrees as called for in the factory specs. This additional advance in timing does not result in detonation and it causes improved torque and a smoother power band.

[911Brian]

That is about where mine was at. I will check my total advance probably this weekend and adjust accordingly.

Thanks guys!

[MotoSook]

Run a search on SC timing or advance, and you will find that lots of guys run with 30-35 degrees of total advance. Feels like a turbo in second gear sometimes when I start to climb the torque ramp just past 3500 RPM hehe..optimistic I know, but man do I love the 3.0. esp. in a very light(er) car.

[1fastredsc]

If the only mark on the pulley is designated for 5 BTDC, how do you measure 35?

[MotoSook]

You should have a Z1 mark..unless your pulley is from I don't know where.

Or find TDC on your pully. Get the No. 1 piston at TDC and mark your pulley with something that will show in the strobe light. Use a long straw or something solf to stick into the spark plug port to verify TDC.


Get Craftsman timing light with a dial advance for the light..about 60 bucks I think.

Or subtract 5 degrees..

lots of ways to get around the problem.

[1fastredsc]

Oh, that would explain it, i didn't know that lights had advance dials on them (the one i have my dad used back in the 70's and is cheap). If i ever get the motor together than i'll do this timing mod. Do you rev it to a certain rev or something with the vac's blocked to get a 30-35 degree advance as described?

[911Brian]

I will do a search. I am curious if there is a way to check total advance with a standard timing light?

Thanks again!

[MotoSook]

30-35 degrees at 6000 RPM. I don't run any vacuum at all

Brian, mark your pully for 30 and 35 degrees. the strobe should light it up when you are close to full advance.

[911Brian]

Thanks Souk! I will have to dust of my protractor and geometry skills

I didn't know if there was a mark already or not.

[MotoSook]

Brian, if yo get your wife's sewing tape..you can figure out the the 35 degrees that way..measure the pulley OD, devide by 36 and you have 10 degree measures..half that for 5 degrees..right?

[911Brian]

Sounds good to me! Although I couldn't really feal a difference between the previous setting and the current one. I will still recheck this weekend. Plus, it is just plain fun playing with my new toy! Give me an excuse to tell the wife that I have to take it out for a drive and drive the piss out of it to see if I broke something