Top dead centre

Hi all, how do I tell when cylinder 1 is tdc? :dontknow:

through the timing hole in the top of the gear box

mark is on the flywheel

Or long screwdriver/ ratchet extension through number one plug hole, let it go down and back up to see tdc.

the piston sits at the top of the cylinder for a few degrees (dwel angle) so the good old dowel down the hole isnt accurate enough to find TDC. it will show you when piston 1 is at the top, nothing more.

as above use the flywheel mark its the most accurate way, its the small punch mark NOT the big diamond.

there is also a notch on the crank pulley which lines up to an arrow on the timing belt cover, but this can be out. the outer part of the pulley can slip round if the rubber damper is a bit worn, i worked on a mk3 8v which was over 90degrees out on the crank pulley!