Engine Pulley Speed

[ChrisH]

I want to check my idle and other engine speeds using an optical tachometer. Unfortunately, I cannot get the reflective sensor to stick to the flywheel as it's too dirty, but I can get it to stick to the bottom pulley off the engine that drives the water pump and hence the alternator.

Does anyone know what speed that pulley will be going at? Presumably it is not at engine speed, or is it?

Be very pleased to hear if anyone knows the answer.

Chris

 

[alewis]

Isn't it half speed as its the cam shaft ?

 

[malcolm]

Agreed - the pulley right at the bottom that drives everything else is the camshaft which turns at half crankshaft speed.

 

[ChrisH]

Thanks for that chaps - sorry for the delay, been away.