Cam Timing During Cambelt Change

[ifcho 0]

We are changing the timing belt and cam on a xu10j2 with one from a d6b engine and while adjusting a question arised. When we set the crank and cam pulleys on the markers and use the tensioner pulley to strain the belt the markers on the crank pulley goes slightly off and the cam goes half a tooth retarded. When we advance the cam with one tooth and then strain the belt the cam stays advanced half a tooth. So which is better, having the cam slightly retarded (as a result of the strain of the belt) or having the cam slightly advanced?

[dcc 855]

you should have the cam and crank pulleys locked in place to stop them from moving.

[ifcho 0]

They are locked and they are not moving, the problem is that when you put on the belt, and you start turning the bottom pulley there is some slack in the belt which results in the cam being retarded a little.

[petert 587]

The harmonic balancer has probably rotated, meaning your bottom pin location is wrong. Either fit a new balancer, or work from first principles.

[ifcho 0]

By harmonic balancer you mean the pulley?

I don't think it is a doulbe-mass one..

[welshpug 1,657]

sounds like the head has been skimmed and the gasket thickness not increased to compensate.

[ifcho 0]

Indeed it sounds like that.

[Matteo 17 1 Cars]

[...] which is better, having the cam slightly retarded (as a result of the strain of the belt) or having the cam slightly advanced?

 

If you advance the cam, you move the power band at lower rews, if you retard the cam, you move to higher rews.