Timing belt issue.

[Ivant]

Hi all. I have a 91 T/T gto. Recently I took the left side timing belt dust cover off to inspect the condition of the belt, and in doing so snagged it on the belt on the right side cam wheel causing the cam wheel to jump two notches forward on the belt. I know I should have been more careful, as I know the right side of the belt can be a little bit loose on the right side going down to the pully when the engine is cold. But it's done now and there's no good moaning about it. The motor still starts first pop, despite a tiny bit of missing. The missing goes away when warm and drives well, but runs a bit rough at idle. I don't want to live with it, and was wondering if I can get the cam wheel back a couple of notches without going through an entire timing belt replacement process, as the belt has only done 27 thousand ks.
Any ideas on the matter will be much appreciated.

[stealthee]

Only way to do it is to do it right.

[box]

Stick a pencil sized allen key between the timing gear and the belt and turn the engine slowly by hand, it should move the belt over a tooth. Never actually tried it on a 6G but it should work....it seems to work on everything else.

It shouldn't have jumped timing that easily IMO.

[Alex3000gt]

Hi all. I have a 91 T/T gto. Recently I took the left side timing belt dust cover off to inspect the condition of the belt, and in doing so snagged it on the belt on the right side cam wheel causing the cam wheel to jump two notches forward on the belt. I know I should have been more careful, as I know the right side of the belt can be a little bit loose on the right side going down to the pully when the engine is cold. But it's done now and there's no good moaning about it. The motor still starts first pop, despite a tiny bit of missing. The missing goes away when warm and drives well, but runs a bit rough at idle. I don't want to live with it, and was wondering if I can get the cam wheel back a couple of notches without going through an entire timing belt replacement process, as the belt has only done 27 thousand ks.
Any ideas on the matter will be much appreciated.

Sounds like the tensioner gave up the ghost and now you’ve got a loose timing belt. Imagine what might happen if all four cams jump timing while the engine is running?

Could be time for a new belt and tensioner. How old (years) are the ones on the motor?

[stealthee]

Sounds like the tensioner gave up the ghost and now you’ve got a loose timing belt. Imagine what might happen if all four cams jump timing while the engine is running?

Could be time for a new belt and tensioner. How old (years) are the ones on the motor?

The problem is the tensioner will "rest" after the vehicle sits. Many people have found the belt to have slack after the car has sat a bit and thought the worst. As soon as the engine cranks the tension is taken up. If you hit it while it is slack then you could potentially cause it to do what happened here.

[Ivant]

Stick a pencil sized allen key between the timing gear and the belt and turn the engine slowly by hand, it should move the belt over a tooth. Never actually tried it on a 6G but it should work....it seems to work on everything else.

It shouldn't have jumped timing that easily IMO.

I might give that a try, as it only needs to go back two teeth for the correct timing. I have found that when the engine is cold the timing belt on the right side going down to the water pump can be a bit slack. But after the engine starts it tightens up. I read somewhere on a gto site that, that can be normal.

[Ivant]

Sounds like the tensioner gave up the ghost and now you’ve got a loose timing belt. Imagine what might happen if all four cams jump timing while the engine is running?

Could be time for a new belt and tensioner. How old (years) are the ones on the motor?

The belt has only done 27 thousand ks. But it was replaced back in 2000. I was a bit worried about it and showed it to my mechanic, and he said it still looked brand new, and should be fine for ages yet. It's really just a weekend car these days and is garaged everyday of it's life. So not getting the heat from hot days on the rubbers etc in the car.

[Ivant]

The problem is the tensioner will "rest" after the vehicle sits. Many people have found the belt to have slack after the car has sat a bit and thought the worst. As soon as the engine cranks the tension is taken up. If you hit it while it is slack then you could potentially cause it to do what happened here.

I think you've hit the nail on the head with you're comments, and are bang on.

[Ivant]

Stick a pencil sized allen key between the timing gear and the belt and turn the engine slowly by hand, it should move the belt over a tooth. Never actually tried it on a 6G but it should work....it seems to work on everything else.

It shouldn't have jumped timing that easily IMO.

On re-reading your comments, it's not the belt that's moved, it's the right side cam gear, moved two teeth forward and needs to go two teeth back. So it's the cam that I'm going to try and move back until it's in it's proper place lined-up with timing mark on the block. The left side cam is properly lined-up, but the right one is two teeth out, and needs to go back.

[box]

On re-reading your comments, it's not the belt that's moved, it's the right side cam gear, moved two teeth forward and needs to go two teeth back. So it's the cam that I'm going to try and move back until it's in it's proper place lined-up with timing mark on the block. The left side cam is properly lined-up, but the right one is two teeth out, and needs to go back.

It should still work.

While you're at it, pull the bottom cover off and make sure the tensioner eccentric pulley has been set up properly, a lot of mechanics cock it up in a way that allows the belt to slacken too much.