VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1929-1932 31 timing at 18 degrees

Have read most of the postings about setting theh timing at 18 degrees but I am more confused now than before. Trying to time the car by myself.

Spark plugs have been set to 40 and so I want to get timing to 18 degrees.

I think of the timing window as having a top and bottom. My 12 degress mark appears at the top of the window and as I hand crank the engine it slowly moves towards the bottom of the window and eventually disappears.

Am I at 18 degress when the 12 degree mark starts to disappear at the bottom of the window.

What happens next?

You are at 18 degrees when the 12 degree timing mark starts to disappear at the TOP of the window, not the bottom. This is done with the engine running and using a timing light!

Skip,

That is why I am confused. I am really being very thick on this one.

When I turn the crank the timing gear goes clock wise. So the 12 degree mark appears at the top and as I turn the crank it moves to the bottom and then eventually out the BOTTOM of the window. The only way the 12 degree mark would disappear at the top is if teh wheel was going counterclockwise.

Why is my brain not figuing this out.

By hand cranking the engine you are getting yourself confused. With the engine running, and when you advance the distributor, and you look at the timing mark with a timing light, the timing mark moves counter-clockwise (which is advanced), not clockwise (retarded), even though the engine is running in a clockwise direction. If you move the distributor clockwise, then the timing mark will move clockwise which is retarded. With the engine running advance is opposite the direction of rotation as viewed with a timing light, and retarding is the same direction as rotation. If you want to hand crank the engine to set the timing, and since you are turning the engine clockwise, then stop cranking the engine as soon as the 12 degree mark appears at the TOP of the timing hole, not the bottom! At the bottom of the hole the engine would be retarded, not advanced.

Look at it this way. With the engine not running and U/C (Upper Center, which is Top Dead Center) set on the pointer, to the right of that would be the 12 degree mark, which is advanced. So, if you want to advance the engine to the 12 degree mark, then the 12 degree mark would have to be on the pointer, which means that U/C is to the left of the pointer towards the top of the hole since the U/C mark is to the left of the 12 degree mark on the flywheel. Now, if you want to go to 18 degrees, which is more advanced, then the 12 degree mark would be at the TOP of the timing hole, the U/C mark would be to the left of the 12 degree mark and out of sight at the top side of the timing hole, and if there were an 18 degree mark on the flywheel it would then be on the pointer. Because of the location of the timing hole on a 1931, an easy lesson to remember would be that to the left of the pointer is advanced (top of the timing hole), and to the right of the pointer is retarded (bottom of the timing hole).

To make it easy on yourself and so that you don't get confused, as stated earlier, set your timing with a timing light and the engine running. Then, when you turn the distributor counter-clockwise the timing mark will advance (same direction as the distributor, counter-clockwise) and keep turning the distributor until the 12 degree mark just starts to disappear at the TOP of the timing hole, which is to the left of the pointer.

Uhuk, yep, shore, right!

(Just take JYD's word for it, thinking about that stuff gives one a headache!)

"A good explanation if I do say so myself, Ollie!"....

When you advance you are getting ahead of normal and when you retard you are getting behind the normal?...

Reminds me of an old Wayland Jenning's song....with a line.."The one on the left is on the right and the one in the middle is a Methodist!"

I think the light just went on in my head. Now it makes sense to me. Will give it a try in the morning. Really appreciate the effort to make me understand.

Yellowcabguy,
I was the same way, if it dissapeared out the window wouldn't that be behind the 12* and be retarding?
but with rotating the distributor while the timing light is on the window is what makes JYD's way work.