Just when I thought I understood A timing...

bbbbut but but Mitch we NEED a December saga. Guess we'll have to wait for something else.

Maybe since we are now in snow season in some places, someone will want to know how to install positraction in their A rearend using cutdown clutch discs from a Model T....surely someone has tried it....
 
tbirdtbird said:
bbbbut but but Mitch we NEED a December saga. Guess we'll have to wait for something else.

Maybe since we are now in snow season in some places, someone will want to know how to install positraction in their A rearend using cutdown clutch discs from a Model T....surely someone has tried it....
Click to expand...

That Synders head milling thing has a chance of the December saga.
 
Last edited:
I think most all of the points made are good and valid. Here is what I learned 50 years ago while working as an apprentice auto machinist. Use the timing marks to set the relationship between the cam and crank Then, bring the #1 cyl. to tdc. The valves will be closed if it is in the firing position. On the A, the dimple for the firing pin will have to be in the correct quadrant for the pin in the timing cover. The cam lobes are both pointing down. The companion cyl. #4 will be up at the same time, they must be exactly in overlap, the lobes are split in the up position with both valves equally in the partial open position. You can tell if cam timing is 1 tooth out if the crank is exactly at tdc. if overlap is spot on. The companion cyl. trick works for 4,6 and 8 cyl. engines.This is just a way to verify that the marks were correct. If the valves are closed on #1 at tdc. the timing could be way out, look to the companion cyl. for the verification you need. A variant of this is also a way to set valve lash. #4 in overlap - adjust #1. Works without fail for me for 50 years. Also reinforces understanding of the 4 stroke cycle, not a bad thing.
 
100IH said:
I think most all of the points made are good and valid. Here is what I learned 50 years ago while working as an apprentice auto machinist. Use the timing marks to set the relationship between the cam and crank Then, bring the #1 cyl. to tdc. The valves will be closed if it is in the firing position. On the A, the dimple for the firing pin will have to be in the correct quadrant for the pin in the timing cover. The cam lobes are both pointing down. The companion cyl. #4 will be up at the same time, they must be exactly in overlap, the lobes are split in the up position with both valves equally in the partial open position. You can tell if cam timing is 1 tooth out if the crank is exactly at tdc. if overlap is spot on. The companion cyl. trick works for 4,6 and 8 cyl. engines.This is just a way to verify that the marks were correct. If the valves are closed on #1 at tdc. the timing could be way out, look to the companion cyl. for the verification you need. A variant of this is also a way to set valve lash. #4 in overlap - adjust #1. Works without fail for me for 50 years. Also reinforces understanding of the 4 stroke cycle, not a bad thing.
Click to expand...
That's how I've always done it. Using companion cylinders is a VERY old technique that seems to have been lost.
Another way to be sure both valves are shut when you want to adjust the valve clearances is to watch the rotor button and adjust the cylinder it is pointing to - assuming the timing is set somewhere near right
 
Even Big glob of thread lock
 

Attachments

  • 20161203_185527.jpg
    20161203_185527.jpg
    36.1 KB · Views: 104
100IH said:
I think most all of the points made are good and valid. Here is what I learned 50 years ago while working as an apprentice auto machinist. Use the timing marks to set the relationship between the cam and crank Then, bring the #1 cyl. to tdc. The valves will be closed if it is in the firing position. On the A, the dimple for the firing pin will have to be in the correct quadrant for the pin in the timing cover. The cam lobes are both pointing down. The companion cyl. #4 will be up at the same time, they must be exactly in overlap, the lobes are split in the up position with both valves equally in the partial open position. You can tell if cam timing is 1 tooth out if the crank is exactly at tdc. if overlap is spot on. The companion cyl. trick works for 4,6 and 8 cyl. engines.This is just a way to verify that the marks were correct. If the valves are closed on #1 at tdc. the timing could be way out, look to the companion cyl. for the verification you need. A variant of this is also a way to set valve lash. #4 in overlap - adjust #1. Works without fail for me for 50 years. Also reinforces understanding of the 4 stroke cycle, not a bad thing.
Click to expand...

100IH, What part of SW Idaho are you in? I just moved to Kuna.
 
I moved #1 to TDC ( both valves closed ) and ignition timing mark was lined up with the hole in the timing cover.
 
Art, aligning the timing camshaft/crankshaft marks and timing the distributor are two different things. You have indexed the cam/camshaft correctly! Now rotate the engine until the timing pin drops into the SAME dimple.(thru the timing cover)[it is almost 160 degrees from the camshaft/crankshaft alignment position] that is TDC--the valves will be right--time the distributor cam and it will just purr like a kitten. Toodles
 
Y'alls eyes are probably better then my 80 year olds but I swear I see the crank gear dimple 3 teeth to the left of where Art has it now:eek:

Sewall
 
Quigley1930 said:
Can't count to well that's four teeth:confused:

Sewall
Click to expand...

Oh great............now we have a new mystery. Why is this last picture showing the timing mark 4 teeth off, while the pictures in #24 and #27 show the timing mark 3 teeth off? :confused:
Maybe you should remove the oil slinger and have a good look at the key.

Here's 2 of the 3 pictures in question.
 

Attachments

  • Timing Mystery 1.jpg
    Timing Mystery 1.jpg
    37.2 KB · Views: 89
  • Timing Mystery 2.jpg
    Timing Mystery 2.jpg
    59 KB · Views: 92
Last edited:
The picture in Les Andrews book shows precisely how the marks are supposed to line up.

I would use that to verify your gears.

Thanks.
 
You must log in or register to reply here.
Back
Top