setting igniton timing-a primer

[So Cal Mark]

Here is a pretty good instructional video explaining ignition timing;
http://setyourtiming.com/video.html

[Hvnfn]

Great link, Mark!! Thanks!

[Kevin1]

Mark,
Any recommendations on what the total timing advance should be on a 2l FI engine? Todd Ryden's book (Building high Performance Ignition Systems) suggests 40 to 44 degrees for engines with a hemispherical combustion chamber. Stock settings for the Fiat yeilds 32 degrees total advance.

[racydave]

Realistically I think its closer to 36 degrees of total advance. Depending on your set-up. I built a dizzy-less system and build a computer program for it. Alot of trial and error involved, but cool anyway.

[Kevin1]

Realistically I think its closer to 36 degrees of total advance. Depending on your set-up. I built a dizzy-less system and build a computer program for it. Alot of trial and error involved, but cool anyway.

Dave! I knew someone on the forum mentioned they had been through this!!! Just couldn't remember who . . .
My advance springs are lighter than the stock springs - full mechanical advance comes in by 2600 - 2700 rpm.
Setting the timing by the vacuum method gave me a best manifold vacuum reading at 16 degrees of initial advance (800rpm). This is quite a bit more than the factory recommended setting of 10, but the car is running great, with no detonation running 98 octane regular. It still runs fine at the stock 10 degree setting, but acceleration is noticeably better at 16.
As for "how much is too much" advance, would no pinging indicate everything's ok?

[So Cal Mark]

where are you getting 98 octane? Our fuel is 89 regular and 91 premium

[Kevin1]

98 octane gas is available at the Dyslexia Gas and Convenience Store, which is exclusive to my part of Maine. I meant to say 89 octane.

[racydave]

Kevin, sounds like you have it pretty close! I get my total adv a little earlier, but you are very close. Never did hear mine ping, but watched the temp gauge. If you get to much total, it will start running hotter.At some point you may burn a piston, or maybe blow a headgasket. Also the fuel milage is a good indicator. Optimum performance is close to optimum milage.

[So Cal Mark]

when you buy fuel at Dyslexia, do they pay you?

[Kevin1]

when you buy fuel at Dyslexia, do they pay you?

Damn, the secret's out. Now everybody will be lining up.
Thanks, Mark!

[Kevin1]

Dave,
I think I'll run the car as is for a while before making any more changes. Haven't driven enough to notice any change in MPG yet, but I can say I haven't seen anything different on the temperature gauge. Currently have one light and one medium spring installed for the advance. Two light springs gave full advance below 2000 rpm, which seemed too early.
All of this ignition fiddling is the result of building a 5 liter motor for the Healey over the winter. Getting it dialed in opened my eyes to just how big a difference getting the timing right can make - compared to stock specs - for that particular engine. In this case tweaking the timing and advance curves made the difference between 320 and 358 hp, nearly a 9 percent increase.
Before that I always just set timing by the book and didn't give it a second thought. Not any more.
This just gets better and better . . .

[pope]

Kevin, you said that you use 98 octane when it should be 89. You said the station is named Dyslexia Gas and Convenience Store, are we to assume the real store name is Aixel Syd Convenience Store and Gas. I'm just saying!

[Kevin1]

The locals just call it "Greasy Sid's" but you've got the right place. Some folks confuse it with the diner.