How many revolutions are required to hand crank a timing belt from Top Dead Center to Top Dead Center?

1 Answer 1


It takes 360° (one full revolution) of the crankshaft for a single piston to go from top dead center (TDC) to TDC. The camshaft(s) takes an additional 360° (720° total) of the crankshaft for it to go a full circle (on a 4 stroke engine, anyway).

Realize, if you were to mark the cam belt where you started with a mark against it and the cam gear, it would take A LOT of turns of the crankshaft for it to realign with the mark again. They make it this way so a thing called sympathetic wear doesn't occur. You don't want the same teeth of the cam gear affecting the same rib of the belt on every turn of the engine. If it did, additional wear would occur (which is sympathetic wear).

To check the belt alignment, you should turn the crankshaft two full turns, then ensure the timing marks on the camshaft(s) and crankshaft align with their respective timing marks. You do this after installation before you try to run the engine. If you feel any resistance, stop rotating the engine and recheck everything.

Hopefully this answers your question.

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