Timing. Which way to go?

Dr.Scientist · May 17, 2011

This is probably a dumb question to many of yall, but I never did much work when it comes to timing, so here goes. I would like to "advance" my timing by 4 degrees like many of you have done to your 302. From the factory, the timing is supposed to be set at 10 degrees before top dead center. So when I'm "advancing" the timing by 4 degrees, do I want to set it to the 14 mark on the balancer, or do I want to set it to the 6 mark on the balancer? I guess its the word "advance" that's throwing me off, on this one.

Cause if you think about it, 10 degrees "Before Top Dead Center" is like 10 degrees retarded timing... right? So if I wanted to "advance" the timing by 4 degrees to gain the free horsepower, then I would "advance" it to the little 6th notch on the balancer. Which would put me at only 6 degrees before top dead center, instead of 10. Right?

Addermk2 · May 17, 2011

advancing your timing is increasing the distance from 0?

so +4? to base would be 14?BTDC

Raffaelli · May 17, 2011

If your timing is set at 10 degrees BTDC, and you advance it 4 more degrees, the timing would now be at 14 degrees before top dead center (BTDC).

Or as some people would say 14 degrees advanced.

Advanced could mean the change of degrees, or the totall degrees before top dead center.

ccasion14:

Paul · May 17, 2011

Be careful. Many of the SN95s won't take that much initial timing without detonating. Listen closely for it, and back it down if necessary.

Paul.

Dr.Scientist · May 17, 2011

Ok. Maybe I should try just 13 degrees then? My motor is a high mileage motor so I'll be careful.

Paul · May 17, 2011

You can try whatever you like at first. Just listen for it, and back it down as necessary.

Paul.

ReplicaR · May 17, 2011

I know that many states have different gas, but in california with 91 octane, the most I could get out of the car before it started to lose power was 12. Going from 10 to 12 was about 8rwhp, but any more than that I was actually losing it. For example at 14 degrees, I was 20whp down on baseline result

Dr.Scientist · May 17, 2011

Thanks for all the help everyone. I really appreciate it. Ok so I'll just try 12 to start with. But I heard something somewhere about needing to pull the "Spout" connector. Never heard of it. LOL. Where exactly is it?

Paul · May 17, 2011

Passenger side inner fender apron, underneath the air inlet tube. Small white connector that plugs into a black plastic "receptacle" on the harness.

Paul.

Dr.Scientist · May 18, 2011

Thanks man. How exactly would you describe the sound of detonation? Does it make a low pitched "poomp" popping sound in the mufflers? Would it make the car a little cold blooded, and then kinda lessen once the motor warmed up?

Paul · May 18, 2011

It sounds like a penny in a pepsi can. Sort of a rattle.

auto_x5.0 · May 18, 2011

So if you make that noise you need to drop timing a little more?

Dr.Scientist · May 18, 2011

Yeah you need to back it down a little closer to 10 degrees before top dead center. From where you had it. Then try again. The goal is to advance it as far as you can with no detonation, and still be able to run 87 octane. I think... lol. Its supposed to be like free horsepower. But I have no idea how much.

toyman · May 18, 2011

Dr.Scientist said:
Yeah you need to back it down a little closer to 10 degrees before top dead center. From where you had it. Then try again. The goal is to advance it as far as you can with no detonation, and still be able to run 87 octane. I think... lol. Its supposed to be like free horsepower. But I have no idea how much.

You beat me to it. The reference to using 87 octane is the base upon which one needs to use in setting the timing.

The SPOUT may be grey as well as white. In any event it needs to be removed (don't loose it either) before setting the timing and you need a timing light to set the timing..

auto_x5.0 · May 18, 2011

Yeah, dont set it by ear...that never ends well, I had trouble seeing the numbers on my balancer tough...is there a trick to this?

Addermk2 · May 18, 2011

Advancing your timing as far as it will go before detonation is NOT the way to reach peak efficientcy. I proved that with my car! I was running 15? BTDC and did not ping or knock, or detonate one single bit. I backed my timing down to 12?BTDC and my HP went up by ~11 IIRC (that was a long time ago). Now I'm not saying that less is better... but MORE is NOT always the answer. You should strive to achieve MBT at any particular RPM/Load. There are many ways to calculate it, but ultimately it comes down to AFR, LOAD, RPM and Temp. With that said, any change to one of those variables, completely skews the calculations, and the results!

Dr.Scientist · May 18, 2011

Ok well now I have a new problem lol. I timed the car a while back, before I knew about the spout connector. So now, the dizzy is of course set to 10 TDC, where I set it. But, the computer would have compensated for that. So now what am I supposed to do? Now that the computer has compensated, I can't possibly know where the dizzy setting actually is. You see what I'm saying? Even though its set at 10 degrees BTDC, it really isn't because the computer is compensating. So now what do I do, to get the computer to think its back at 10? And at the same time, actually have the distributor set to 10? The whole thing is thrown off now.

Paul · May 18, 2011

Pull the spout, and set to 10* BTDC on the balancer. If the spout is out, the computer cannot change timing. You're only setting base timing. The timing/load tables in the computer take care of the rest.

Paul.

Addermk2 · May 18, 2011

Dr.Scientist said:
Ok well now I have a new problem lol. I timed the car a while back, before I knew about the spout connector. So now, the dizzy is of course set to 10 TDC, where I set it. But, the computer would have compensated for that. So now what am I supposed to do? Now that the computer has compensated, I can't possibly know where the dizzy setting actually is. You see what I'm saying? Even though its set at 10 degrees BTDC, it really isn't because the computer is compensating. So now what do I do, to get the computer to think its back at 10? And at the same time, actually have the distributor set to 10? The whole thing is thrown off now.

You have yourself WAY confused. The ECM ALWAYS thinks the base timing is 10 degrees... ALWAYS. Once you pull the spout out and move the distributor... the car has no clue that you have changed anything. When you put the spout back in, all it does is re-advance itself the same amount it would have before. Regardless of where you have set the base timing.

Basically, If the car wants to add 14degrees of timing, and your base is set to 10. when you plug the spout back in, your timing will jump to 24. If you had only set your timing to 6 degrees, it would only show 20 degrees on your balancer with the spout in.

Do you get it now? Don't try to give credit to the computer for being smarter then it really is.

Dr.Scientist · May 19, 2011

Yeah I get it now, thanks for all the help guys. Basically all you do is pull the spout and set it where you want it. I was thinking that the computer was like actively checking to see where the timing was and compensating, sort of like it does with the oxygen sensors.