I'm working on my 2nd timing belt change. We all know that makes me a PRO. So, my question is... why is it SO important to align the timing marks when doing the belt change?

When I remove the belt, it seems that the crank at the bottom of the engine, and both cams at the top of the motor are so hard to turn that they will not move without some serious effort. If I just pulled the belt, and nothing moved, and installed the new belt, wouldn't everything be ok??? Or is there something that would cause these parts to turn if the belt is removed without aligning the marks???

Another question/comment... If I pulled the belt without aligning the marks, then aligned the marks when putting the new belt on, do I risk damage because I did not align before belt removal???

Just hoping to learn a little about the process. Maybe others as well. If we can't come to any conclusions I do give ANYONE the permission to test the process out and let us know what happens.

 

I've had cams "flip" a bit, all it takes is for the load imposed on the cam lobes to be a little uneven and one valve will push the cam lobe out of the way.
My motorcycle is horrible for this.

Regards, Andrew.

 

So what I hear you saying is that cams, etc. in the motor can have pressure on them when the motor is linned up that pressure is relie ved?

 

If you did not line up the marks and removed the belt and want to line them up going back together it can be done.

You have to do it carefully though.You can move the cams a little at a time and then turn the crank a little to let the cams move more. Then turn the crank back some and keep going till you get the marks lined up. Make sure you turn them slowly and easy.

 

If you done align them, and take the belt off and put it back on, will all turn out ok?

 

Do you mean just putting the belt back on?
You will be fine as long as the cam did not turn at all.

But if you put the belt on and turn by hand slowly and it is off as long as you turned by hand nothing should be bent.

Put the belt back on and then turn it by hand and try to line the marks up and see if they are good.