Timing mark question

GregL · Post by **GregL** » Mon Sep 28, 2009 1:32 pm

Finally got around to doing the timing yesterday, and eventually found the marks on the pulley. The middle line is "0C" which I assume is TDC (and which seemed to correspond to the number 1 piston being at the top of it's travel), then after 10 lines on both sides of 0C is the number 10, which I assume is 10 deg. Sorry for the naive question, but which direction is "before" and "after"? Is it as simple as BTDC being to the left of TDC on the pulley?

It looks something like this:

BTW, it's amazing how well this thing runs when the points are gapped properly!

m15256 · Post by **m15256** » Mon Sep 28, 2009 6:06 pm

Simple backwoods method. Look at your fan. Imagine which way it would rotate to suck air through the radiator. Turn your engine over with the starter but ignition off. Still rotate the same way you imagined? Visualize the crank shaft pulley rotating to make the fan go the right way. Turn your engine by hand that direction (ignition off). The little marks that pass the pointer before the zero mark are BEFORE TDC. Obviously the other ones are AFTER TDC. Good luck.

Lifer · Post by **Lifer** » Tue Sep 29, 2009 3:45 am

Like he said. You don't have to actually turn the engine over, though. The crankshaft rotates clockwise when looking at it from the front, so the markings to the right are before TDC. The markings to the left are after TDC.

GregL · Post by **GregL** » Tue Sep 29, 2009 5:44 am

Well, of course, makes perfect sense now!

Why didn't I think of it before? I'll blame it on pain medication for a bum tooth.

Thanks!