06-20-2022, 05:42 AM | #1 |
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Join Date: Jul 2012
Posts: 28
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timing
I was having trouble timing my Model A so a friend of mine came over to help. After insuring that the distributor was in good shape and the point gap was set at .022, he set the timing so that when completely advanced, it was at 28 degrees. Car runs great now but was wondering what the opinion was of this method of timing.
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06-20-2022, 06:50 AM | #2 |
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Location: Largo Florida
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Re: timing
If everything is as Ford meant it to be, then the timing will be quite a bit retarded at startup. 28* at full advance is fine for most driving, but a tad low.
Timing should be right at TDC [0*] for startup and adjustable to 40* BTDC. [ which I think is too high] So, drive it for awhile then when the points block wears and the gap closes up a bit just reset the point gap to .020" and reset the timing. |
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06-20-2022, 09:07 AM | #3 | ||
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Re: timing
Quote:
https://www.fordgarage.com/pages/bdi...toradvance.htm Quote:
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06-20-2022, 10:50 AM | #4 |
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Re: timing
Has anyone seen a plausible theory for why the quadrant permits 40° total advance, when Ford specifically didn't design the engine to run that way? Potentially they might have designed it to span from -10 ATDC to 30 BTDC, but this isn't supported by the factory timing instructions that I've seen. Perhaps it was designed so that it could be modified to start at -10 in extreme conditions?
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06-20-2022, 11:45 AM | #5 | |
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Re: timing
Quote:
Ford really was "behind the times" in centrifugal or other advance. I watched the two NuRex vids on Youtube and according to him MOST other makers had made the change to centrifugal advance by the time of the Model A. Joe K
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06-20-2022, 12:44 PM | #6 |
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Re: timing
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You had to fiddle constantly with the timing on a stock Model T. The operator served the function of the engine computer in a modern car. The magneto timing varies all over the place depending on the rpm. Ricardo also said that if you are running very lean you have to have much more advance because the flame burns a lot slower. Who knows what the Ford engineers were thinking of but maybe they just wanted to cover all the bases. It could also be because of the difference in fuel back then. If the spark advance range is a problem for someone they can add stops to limit the travel. This might be valuable if someone not familiar with Model A's borrows the car.
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A is for apple, green as the sky. Step on the gas, for tomorrow I die. Forget the brakes, they really don't work. The clutch always sticks, and starts with a jerk. My car grows red hair, and flies through the air. Driving's a blast, a blast from the past. Last edited by nkaminar; 06-20-2022 at 12:51 PM. |
06-20-2022, 12:46 PM | #7 | |
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Re: timing
Quote:
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06-20-2022, 01:45 PM | #8 |
Junior Member
Join Date: Jul 2012
Posts: 28
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Re: timing
Thanks to you all for responding. I had never heard of timing this way and according to your responses, I understand the physics behind it. After timing the old fashion way (top dead center) I was skeptical about using a new system. Thanks again guys.
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06-20-2022, 02:26 PM | #9 |
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Location: Santa Rosa, CA
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Re: timing
I have the same issue on my pickup. A Snyder 6-1 head and B cam. Have timed it so 20* is max advance. Obviously retarded on start, but no problem. Easy start, and heats up faster in cold weather. I just start it retarded and advance as soon as it gets running smooth.
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06-21-2022, 12:55 AM | #10 |
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Re: timing
the idea of maximum advance of 28 degrees was proven a long time ago to be the ideal for 4 cylinder motors. There is nothing about a model A that sets it apart from other 4 cylinder engines. It used to be that a driver of a Model A would learn how his car ran best. Nowadays people are looking for a hard and fast rule and that's unobtanium. Minimum advance at idle is very flexible. If there is a total of 40 degrees available I think it would be best to time it at 28 degrees at full advance a let the minimum be where it ends up.
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