I have this 2001 Volvo v40 that needed all the front seals replaced so in the process I was going to change the oil soaked timing belt. Only problem is I forgot to set TDC for the crank pulley before accidentally came off. So the current state is that the timing belt is off and I have no clue if cylinder 1 was on compression or exhaust stroke. I know I can find TDC through spark plug hole with a long metal stick but won't it matter if it's compression/exhaust stroke? I need someone who's been here or knows more than I to help me out because I'm screwed right now! Thanks for any help/advice.

 

Has anything shifted since you took the timing belt off? Could you put the timing belt back on, tighten it, and then set to TDC?

 

Sadly, yes. Give or take one rotation. Timing belt is off as well as the crank pulley.

 

the reference to exhaust vs compression stroke is for the cam to crank timing. think of it as the cams turn twice for every turn of the crank so the piston is TDC twice in each cycle. If you can guess TDC with a rod, then you can set cam timing via their marks. This means your question is how do you know if you are 180 off or not. Google for some tricks on how to determine that and you should be on your way.

 

This is interesting. Might spark an idea.

 

I should point out that one of the contributors above made a mistake ----it is the crank the turns two rotations for each single rotation of the cam.

 

correction noted :-)