Is this where the TDC locking tool goes on the blacktop zetec?
Rescued attachment TDC Plug.JPG

I think it is although I tried to make a locking pin and use that hole, but gave up as I couldn't seem to find anything inside the hole for it to go into.

I ended up using a dial gauge on No1 to find TDC.

Stu

Yes it is.

You fit the pin and then slowly turn the engine until the crankweb comes up against the pin.

It's a clever idea and intrinsically more accurate than a dial indicator, so long as the pin is correct length and no dirt under the head.

For an engine at top dead centre with 80mm stroke the piston movement for 1 deg of crank movement is about 0.007mm.
Using a pin the difference in pin length for 1 deg crank angle is approx 0.6mm

Of course my copy of Excel could be wrong

Ive had a clock on mine and was shocked by the amount of dwell.