Just when I thought I understood A timing...

Here's a picture of a crank gear from Brattons, look at my picture. the timing mark on my gear is four teeth to the left of the key, on Brattons it's just to the right of the key
 

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'TDC is TDC, if I rotated the crank one turn, it would be right back in the same spot.'

The piston will be "back in the same spot" but the valves will not be in the same spot. See Vince above. Thanks Vince. Rotate it and view it visually and you will get it. The marks are fine, don't worry about them being in the wrong place.


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Art Newland said:
I think the crank gear is just marked in the incorrect spot, weird but just my luck...
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I think so too. On the following 3 pictures, check the position of the mark on the crank gear relative to the key.

Here's Art's...

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Here's the red book...

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Here's a pic Tom posted on another thread...

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The red book and Tom show the crank gear timing mark about 1 tooth to the RIGHT of the key. Art's is about 3 teeth to the LEFT of the key.
 
I actually checked this before I pulled the crank out, who-ever put the engine together before me aligned it the same way... which would only be natural I guess. The mark is very small, I'll make a bigger and better one where it's really supposed to go.
 
forever4 said:
What does that mean, the valves are rocking?

The valves are closed at #1 TDC timing position, not open or "rocking"
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Valves are said to be rocking when the piston is at TDC at the end of the exhaust stroke and you move the crank shaft back and forward a little. Forward and the inlet starts to open, back and the exhaust starts to open. It takes very little movement of the crank shaft to get them rocking. As I said, this is at the top of the exhaust stroke, which is exactly one revolution from compression stroke. While No 4 is at the top of the exhaust, number one is at the top of the compression stroke which is where you want it to be for timing. That is, with the Model A firing order of 1,2,4,3, get the valves rocking on No 4 and you're good to time it - No 1 is at TDC on the compression stroke.
Sounds to me like you have confused yourself with the two dimples in the timing gear. Barring you being super unlucky and having a gear that has been marked incorrectly, you can't go wrong. The crank gear AND the camshaft gear can only go on one way. It's only the relationship between the two that we have to get right.
 
Good catch by Vince and Dick re the crank mark being off. I missed it. Where did it come from?
As my guru says, assume nothing is right. Check and measure everything.
 
Tom Wesenberg said:
Henry liked to be different, so he timed the cam to the crank without caring where the ignition timing was at that time.

So they are two completely different operations, and NOT done at the same time.
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With the Model A ignition timing as flexible as it is (you can move it where ever you want) I guess it really doesn't matter what method Ford used to time the cam.
 
I agree with those saying the mark on the crank gear is off by 4 teeth. Art, your kind of luck is very familiar to me.:D
I also agree with marking the correct tooth on the crank gear (go 4 teeth clockwise) and meshing them again. I think you'll find things are right then.
 
PC/SR said:
Good catch by Vince and Dick re the crank mark being off. I missed it. Where did it come from?
As my guru says, assume nothing is right. Check and measure everything.
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Actually 1955CJ5 caught it way back in post #9:)

assume nothing is right
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this is exactly why I was checking it in the first place.:)
 
Thanks for everyone's input, I know what I need to do now.
Mitch... get a bigger screen. 8^) The mark looks like a punch mark and is hard to see in the picture.
 
forever4 said:
Unfortunately your comments above have nothing to do with a Model A Ford engine and are all wrong/misleading in this context and in this thread.

Now you are injecting discussion of valve position on number 4 cylinder to inject more confusion into this very simple arrangement. Why?

An investment in the Ford Service Bulletins would be a worthwhile expenditure.

Number 1 piston TDC for timing purposes is top of the compression stroke, not exhaust. It automatically happens when the correct timing cover is used and the proper cam and crank gear are properly meshed.

It has nothing to do with #4 cylinder or rocking valves.

Both valves are closed at #1 TDC, not open or "rocking". The distributor is spark timed at #1 TDC, not some other condition.

It is all fully explained on my web page link posted elsewhere on this thread.
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You clearly didn't understand what I wrote. I stand by it.
 
Well the boys got it figured out pretty quickly:::: its a good thing you decided to double check things or this could have been our december saga:D
 
Mitch//pa said:
Well the boys got it figured out pretty quickly:::: its a good thing you decided to double check things or this could have been our december saga:D
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Agree, that was a very fortunate check.
I've never seen a thread go to 3 pages so quickly.:D

I saw that tiny mark, but thought it was just a nick from handling or some such. I was also wondering if the gear might be on backwards and have a timing mark on the other side?
Use a dental mirror to check the back side teeth next to the keyway.
 
frank55a said:
I can not tell clearly from your pictures, however remember the crank makes 2 revolutions to 1 of the timing gear. Your crank might be 1 revolution off. What is the position of the number 4 piston and the valves for cylinder #4? 1 and 4 should be at TDC with the indent in the timing gear lined up for the pin however the exhaust valve for #4 should be open and all valves for #1 closed.

I think if you took the timing gear off, rotated the crank 1 full turn so your marks line up again I think you will be fine.
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Nope! One full turn of the crank will put you right back where you started. No change.
 
forever4 said:
Unfortunately your comments above have nothing to do with a Model A Ford engine and are all wrong/misleading in this context and in this thread.

Now you are injecting discussion of valve position on number 4 cylinder to inject more confusion into this very simple arrangement. Why?

An investment in the Ford Service Bulletins would be a worthwhile expenditure.

Number 1 piston TDC for timing purposes is top of the compression stroke, not exhaust. It automatically happens when the correct timing cover is used and the proper cam and crank gear are properly meshed.

It has nothing to do with #4 cylinder or rocking valves.

Both valves are closed at #1 TDC, not open or "rocking". The distributor is spark timed at #1 TDC, not some other condition.

It is all fully explained on my web page link posted elsewhere on this thread.
Click to expand...

Might want to back up the bus a bit here. Synchro909 has it exactly right. His method has everything to do with a Model A! What he is describing is how to time the cam properly without using the marks. So no matter if the marks are missing or in the wrong spot. Just ignore them and follow the method he described. Remove either the cam or crank gear and set the cam as he described (it will actually 'snap' into position from valve spring pressure). Set #1 piston at TDC (there is no "compression" or "exhaust" stroke at this point). Now reinstall the gear you removed, fiddling as necessary to end up at TDC without moving the camshaft. Done!
 
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