Timing marks and TDC

CedBobKing · Post by **CedBobKing** » 27 May 2021, 18:25

Are the timing marks on the crank and cam sprockets TDC cylinder number one? I know I could check, but I would have to take a car off the road to do it and would like to know before I start planning some work.

I dug around in my Vida and did not find any mention other than how to find the marks.

Thanks in advance.

Post by **abscate** » 27 May 2021, 18:30

They are close to but not at TDC one.

They are non interfering Mark’s, the place where the pistons will not touch the valves during any rotation of the crank and cams aligned to these marks

Post by **erikv11** » 28 May 2021, 01:39

abscate knows what he's talking about here, big time, but his post conflates things.

Only the crank mark is a non-interference mark, putting number one just off TDC and the others more off TDC. With the crank on the mark you can remove the timing belt and rotate the cams freely without any worry of valve-piston contact. But put the cams back on the mark before you out the timing belt back on.

The cam marks are not non-interfering in any way: you should never rotate the crank with the timing belt off. The cam marks just match up the cams to the non-interference mark on the crank.

Post by **abscate** » 28 May 2021, 04:14

That clarifier, courtesy of Professor Potato, is completely correct

CedBobKing · Post by **CedBobKing** » 28 May 2021, 04:31

Understood. Thank you for making that clear.