When working out the firing order of your engine the phrase Top Dead Centre TDC is referred too.

 

In all 4 stroke engines there is two revolutions (720 degrees) of the crankshaft per 4 strokes in the power cycle.  This means that for every power cycle the piston is at TDC twice.

 

In terms of ignition timing etc as the full 4 stroke cycle passes thru 720 degrees......

 

Is 0 deg TDC always referred to as the point between the compression and the power strokes, i.e. the point of ignition.  Which is one complete revolution (360 degrees) of the crankshaft after that particular piston has started on its 4 stroke cycle.

 

Or is 0 deg TDC referred to as the point when a particular piston starts its induction stroke at the begining of that particular pistons 4 stroke cycle.

 

In the days of when cars had ye olde distributors and points, this was all known about, but has lost its way now as cars have a 'puter to tell the sparks when to fire.