Timing Issues Relived (Corellian Corvette you there??)

[Anonymous]

Steve

Really good explanation!

I will agree with others on the board that ‘Total Timing’ is the same thing as ‘All in’ in that it includes Initial + Mechanical + Vacuum.

Also, I think you may have complicated the procedure to determine mechanical advance, although there are several ways of going about it. The easiest would be simply to look at the advance weights for markings, because Ford distributors (I believe) have numbered weighs. Another way would simply be to subtract initial from total to get the mechanical number (38º-14º = 24º). In general, 36º- 38º is the maximum you want to run Initial+Mechanical. If you’re running that much mechanical you need to dial back the Vacuum so your Total Advance does not exceed 52º-54º

To adjust Vacuum Advance you can also put one of those MitiVac units and draw a vacuum to see how much Vacuum Advance your can is pulling.

Anyway, I ended up fixing my problem by putting some welds in the weighs to get my mechanical advance down to a reasonable level. Turns out my engine is able to run a ton of advance without ping, but the car wouldn’t rev past 3000 – 3500 RPM. With my advance fixed I can now get to the 4K + range and it seems to be running much better!

 

[Anonymous]

Corellian,
About time!!
Your post was one of several and the most recent dealing with this so I hope you didn't mind my using it as the example. The others were almost identical with the concepts and verbiage.

I should point out there probably isn't a wrong answer to the "total" concept of timing. The point I wanted to get across was that it was being flipped back and forth within a Subject and was confusing. I've seen dozens of articles and technical publications in defense of either adding or not adding vacuum to the equation. I've also seen a few that listed both and referred to both as "total". To the laymen this was confusing and when we're dealing with a variance of 38° and 55° (examples) and both are referred to as total it was down right scary. I was somewhat disappointed I didn't receive more support from several members here who have posted on this subject. Just to make it more dicey. I can accept either way, when I see the word total and an advance around 38° it's without vacuum, over 50° has to be with it.

Corellian what did you end up with for Initial timing?

Steve

 

[Anonymous]

You're totally right I think there is some difference in terminology - as was stated above it doesn't matter *that* much so long as you explain your definition.

I think the biggest confusion is that people think that timing should be 38deg TOTAL, including Vaccum, and you're going to severly reduce engine power to try and achieve that number.

IIRC, I think I ended up around 17 inital, but I had to do some Voodoo on my advance weights because they were 32 (!) deg weights and the car won't idle well with only 4deg initial. For the most part your initial advance is irrelevant. It's more important to get that curve to smoothly hit 36-38deg mechanical at 3000 rpm or less. Wherever you end up at initial is just a factor of that.

 

[Anonymous]

Corellian,
You probably have been following Jimbo65's saga of his timing, he's also at 17° Initial. Kind of interesting 3 of us have found that # as the sweet spot. I posted to him about his temperature's to see if they've dropped. Also he's going for a Dyno sometime soon. Surprised he hasn't posted on this string but I'm hoping his dyno numbers include the mechanical and totals.

Steve