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Old 12-18-2020, 04:51 PM   #1
Mulletwagon
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Default 2-3 Shift Point Speed

Shifting the old 31 Tudor from first to second can be done at a very slow speed with no problem. My question is the second to third shift. My engine lugs if I shift much below 30mph which makes me feel like I am winding it out in second higher than should be necessary. Sort of feels like I should have a four speed trans with a gear in between my actual second and third to get me up to cruising speed. At what speed do most folks typicall shift in to third ? Could my spark timing be over or under advanced to support a lower speed shift point ? Just seems like the engine is turning too slow to drive in third at 25mph or less. Watcha think ?
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Old 12-18-2020, 05:00 PM   #2
BRENT in 10-uh-C
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Default Re: 2-3 Shift Point Speed

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Originally Posted by Mulletwagon View Post
Shifting the old 31 Tudor from first to second can be done at a very slow speed with no problem. My question is the second to third shift. My engine lugs if I shift much below 30mph which makes me feel like I am winding it out in second higher than should be necessary. Sort of feels like I should have a four speed trans with a gear in between my actual second and third to get me up to cruising speed. At what speed do most folks typicall shift in to third ? Could my spark timing be over or under advanced to support a lower speed shift point ? Just seems like the engine is turning too slow to drive in third at 25mph or less. Watcha think ?
It sounds to me like you have something wrong with your engine. With a totally stock engine, and a stock 3.78 rear end gear ratio, you should have shifted into high (3rd gear) by the time you have accelerated to 15 mph. The Ford Instruction Book recommended 12 - 15 miles an hour as the shift point. If your engine is lugging at 12 - 15 miles per hour, then it is likely that the camshaft is worn -or the engine is down on power.

Even when I have 3.54 gear ratio and a high compression head in a Model-A, I can turn a corner at 15 - 20 mph, -remain in 3rd gear and accelerate back to speed without the engine lugging or bucking.
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Old 12-18-2020, 05:06 PM   #3
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Default Re: 2-3 Shift Point Speed

Brent has some good comments. Go with that. But I want to add that the Mitchell overdrive splits between second and third, about half way. so that, in my car, I find myself driving in second high a lot of the time when on residential or mountain roads. I have a lightened flywheel and shit into third at about 20 to 25 or more depending on circumstances.
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Old 12-18-2020, 05:18 PM   #4
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Default Re: 2-3 Shift Point Speed

It appears something isn't correct. I can actually start in second with very little effort If I choose. I agree with Brent, you shouldn't have to rev the engine at all. If your engine is retarded to much you will lack power.
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Old 12-18-2020, 05:27 PM   #5
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Default Re: 2-3 Shift Point Speed

2nd to 3rd at speeds above 20 you better be double clutching! My normal up shift 2-3 is below 20 mph, I’am not lugging. Slowing down 20 to 15 mph then I may down shift, it depends on the road conditions! but I can accelerate in 3rd at those speeds. I’am with Brent that you probably have issues with your engine.
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Old 12-18-2020, 05:34 PM   #6
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Default Re: 2-3 Shift Point Speed

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I'll just throw this out there. When I got my A someone had timed it backwards... Just sayin.
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Old 12-18-2020, 05:39 PM   #7
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Default Re: 2-3 Shift Point Speed

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I'll just throw this out there. When I got my A someone had timed it backwards... Just sayin.

That's interesting! Since base timing with the timing lever all the way up is at top dead center, how was it timed backwards?
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Old 12-19-2020, 03:22 PM   #8
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Default Re: 2-3 Shift Point Speed

Problem solved. Turns out I was not using enough advance. Typically I start full up on the timing lever and drop down to 1/3 to drive. Tried 7/8 to full advance and it runs fine at 20 mpg. At full advance still did not have any pinging. Suspect every engine is different, but in general, can full advance at slow speed be damaging over time ?
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Old 12-19-2020, 08:09 PM   #9
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Default Re: 2-3 Shift Point Speed

Here is my 2 cents regarding timing. There are several people who will disagree, which is fine with me.

The timing is advanced because it take time for the flame front to burn the fuel/air mixture and build up pressure. The idea is to have the pressure fully built up at top dead center. The time it takes for the burning to take place is tied to the turbulence in the combustion space. That is why the head has a squish area to make more turbulence. As the engine speed increases the turbulence is greater and the fuel/air mixture burns faster. With some minor exception, a constant setting of advance lever will work well from idle to full speed. With my car, after starting, I set the advance two or three clicks from full advanced and leave it there.

The best spot for the advance lever is different with each car and can be found by experimenting. Pick a hill and slightly retard the spark until the speed starts to drop off. Advance the spark a little at a time until the engine no longer increased in speed. The knee where the engine is performing best but advancing more will do no good is the correct advance. Some people with better hearing than I have may be able to hear an ignition knock with too much advance.
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Old 12-20-2020, 12:02 PM   #10
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Default Re: 2-3 Shift Point Speed

Mine also likes the spark advance set about 3/4 of the way down, and on our busy surface streets here in S. California I shift from 2nd to 3rd at around 20 mph. Even though you can shift at 15 mph, there is a huge gap between those 2 gears, and I find 3rd accelerates better at that speed.
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Old 12-20-2020, 12:42 PM   #11
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Default Re: 2-3 Shift Point Speed

Your engine runs best at 1 degree per 100 rpm,max 26 degrees..stock engine is very tolerant of improper timing. Setting the lever means your timing is correct at a specific rpm.
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Old 12-20-2020, 12:42 PM   #12
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Default Re: 2-3 Shift Point Speed

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Originally Posted by Mulletwagon View Post
Problem solved. Turns out I was not using enough advance. Typically I start full up on the timing lever and drop down to 1/3 to drive. Tried 7/8 to full advance and it runs fine at 20 mpg. At full advance still did not have any pinging. Suspect every engine is different, but in general, can full advance at slow speed be damaging over time ?
Last year I was out for a long ride, my car started to run bad, the weather was changing getting cooler and the wind was picking up. I kept messing with the advance, gav but nothing helped, so I headed home. Wondering what happened so I began checking things, what I found was the points gap had closed down to about .015 and the follower had worn, this was after a new points replacement ! I went for another ride and everything was good. Soooo when the points gap closes your engine is running more retarded, if your base timing is retarded and the points gap closes the more advance you need to have the lever. When you find you need to run with the lever down, you should be checking the points!
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Old 12-29-2020, 08:41 PM   #13
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Default Re: 2-3 Shift Point Speed

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That's interesting! Since base timing with the timing lever all the way up is at top dead center, how was it timed backwards?
Lever at the bottom... I'm surprised the thing would even start..
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Old 12-29-2020, 09:44 PM   #14
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Default Re: 2-3 Shift Point Speed

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Lever at the bottom... I'm surprised the thing would even start..
It'll start OK but there is a great risk of it kicking back and either jamming the starter or bending the shaft.
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