No timing marks on pulley!

[Condre']

I need to time the engine on my 56 cub but I can't find the two timing marks on the pulley. Could they have rusted off?

[john2189]

My 72 doesn’t have any marks either

[Jim Becker]

No. They are notches in the rear flange of the pulley. They may be full of dirt and grease.

[Gary Dotson]

Some reproduction pulleys were made with no timing notch, you may have one of those. An original pulley will have the notch (or notches) but may be full of crud, like Jim suggested.

[john2189]

I cleaned and scraped mine with no notches. It has a Steiner head too, so the pulley could be aftermarket.

[Qtr Milr]

You can remove the number one plug and insert something like a zip tie and rotate the engine to see when the piston is at TDC. Then you can time it.

[Dale Finch]

You can remove the number one plug and insert something like a zip tie and rotate the engine to see when the piston is at TDC. Then you can time it.

...and make a mark on the pulley when you are sure the piston IS at TDC.

[ricky racer]

Does the key on the crank correlate with TDC? I never checked that. What I'm asking is, is the keyway at the 12 o'clock position when #1 piston is at TDC?

[Eugene]

You can remove the number one plug and insert something like a zip tie and rotate the engine to see when the piston is at TDC. Then you can time it.

Perhaps, you would be close. Dial indicator would be much better.

There is approximately a 15 degree crankshaft rotation while the piston is stationary at the top of the piston's movement.

Does the key on the crank correlate with TDC? I never checked that. What I'm asking is, is the keyway at the 12 o'clock position when #1 piston is at TDC?

Yes.

[Glen]

Hi,
Below are pics from TM Tractor of the front pulley.
The 1st pic is from the rear of it, showing the keyway, and the timing mark for TDC, at the upper left.
It is a 1 mark pulley, but it is turned so you can see where the mark would be, turned to TDC.

The 2nd pic is a 2 mark pulley, which a 1956, or 1972 Cub would have, but it is turned to a different position. You can turn your phone, or whatever your have, around so the keyway is at the top, and see where the marks are.

The 3rd pic shows the 2 marks from the side.

[john2189]

Does the key on the crank correlate with TDC? I never checked that. What I'm asking is, is the keyway at the 12 o'clock position when #1 piston is at TDC?

Can you see or tell where the key is?

[ricky racer]

If someone has an uninstalled pulley they could probably measure the distance from the keyway to the notch around the circumference and provide you a pretty accurate location.
I'll have to look when I get home to see if I've got one in the barn.

[Jim Becker]

If you need to find TDC and the pulley has no notch, there is a straightforward way to find it, and to do it accurately.

Remove the #1 spark plug. Insert some solid object into the cylinder that will reliably and repeatably block the piston from reaching TDC. Slowly rotate the engine forward until the piston bumps the obstruction. Mark the pulley at the timing pointer. Slowly rotate the engine backward until the piston is again stopped. Mark the pulley at the timing pointer. Measure half way between your two pulley marks and put a permanent mark there. That will be TDC. Don't forget to remove the object from the cylinder and reinstall the spark plug.

I've never done this with a Cub engine. So I don't have a suggestion for what type of object to use in the cylinder. In some engines, a junk spark plug can be modified to do it.