No 1 Piston relation to timing marks

[JSeery]

The timing gear on the camshaft has nothing to do with piston position in the cylinder. If a pressed on timing gear slipped (or a keyed one was miss marked) the valve timing would be off, but it would not have any effect on the crank timing gear position or it's relationship to TDC. The crank timing gear uses a key to establish it's position on the crankshaft. Now, I'm not sure that the crank is at TDC when the crank timing gear dot is straight up. I would have to check that to see. But, the timing gear marks are not there to establish TDC, they are to establish the correct relationship between the crank and the camshaft (cam timing).