Al

 

Let me offer this idea. If you know where the tip seals are, then you

can derive TDC. Level the base of the engine, and the tip seals should

line up verically. Pull the trailing plug, rotate the shaft until the

tip seal shows up in the first chamber, then make a mark on the starter

ring gear. Rotate the engine until the next seal shows up, and make

another mark. Count teeth to get the center one, or make the two marked

teeth line up vertically. This would eliminate the importance of the

spark plug hole location.

 

I'm not sure I understand this; but it suggests the assumption that the

TDC position is at the trailing plug hole. - which I don't think is correct.

 

Al