Timing belt tensioner

[Raus]

Need some input on this, I replaced the belt and tensioner and when I was adjusting the tensioner I put in an 8mm allen key between the tensioner roller and tensioner, then I turned the eccentric adjuster to where it was pointing before and locked it up.
Problem is after the car ran for a couple of minutes the space went down to about 3mm.

So I used the 8mm spacer again, then backed off the eccentric adjuster and retightened. After a couple of minutes of idling the tensioner stayed where it was. I just went for a 20 minute drive came back and the space has shrunken down to 6-6.5mm. Is this ok now?

[Raus]

Does anybody know?

[03 silverbullet]

well the DIY says between 6 and 10 i set mine to 7 mm

[ApexIt]

is there a reason as to why you can set it anywhere between 6 and 10mm? Is there an advantage or disadvantage to running one or the either?

[Raus]

well the DIY says between 6 and 10 i set mine to 7 mm

I know that, just wondering about the movement. Both times I tensioned it, manually rotating the crank around didn't compress the piston in the tensioner. It only did after it ran.
Checked the gap again today and it's definitely 7mm, I called it done and put the cover back on.

numer24, no adavantage the way I understand it. That spacing is a compensation for the right amount of tension on the belt. If you have too much pre-tension on the eccentric adjuster, the tensioner will compensate by the piston compressing to ease the tension on the belt (narrow the gap). If you have too little pre-tension, the piston will move up to put more tension on the belt (bigger gap). It can only compensate so much, too tight and the belt might snap, too loose and the belt might skip a tooth. That's what I figure.

[03 silverbullet]

I know that, just wondering about the movement. Both times I tensioned it, manually rotating the crank around didn't compress the piston in the tensioner. It only did after it ran.
Checked the gap again today and it's definitely 7mm, I called it done and put the cover back on.

numer24, no adavantage the way I understand it. That spacing is a compensation for the right amount of tension on the belt. If you have too much pre-tension on the eccentric adjuster, the tensioner will compensate by the piston compressing to ease the tension on the belt (narrow the gap). If you have too little pre-tension, the piston will move up to put more tension on the belt (bigger gap). It can only compensate so much, too tight and the belt might snap, too loose and the belt might skip a tooth. That's what I figure.

Well at least you got the problem fixed and the car running again

[akaEsCo01]

It went down because if you tighten the tensionser as tight as it was before it will be too tight on a new belt. An old belt is worn and needs more tension, a new belt is already tight and thick therefore needing less tension

[Raus]

It went down because if you tighten the tensionser as tight as it was before it will be too tight on a new belt. An old belt is worn and needs more tension, a new belt is already tight and thick therefore needing less tension

No. Don't say stuff like that if you don't know what you're talking about.

Once the eccentric is locked in place that's it, it's done on a new belt (as it was done on mine) and stays in the same position regardless of belt wear.

[akaEsCo01]

No. Don't say stuff like that if you don't know what you're talking about.

Maybe I misunderstood you or you may not have understood my response. I have done a few timing belts in my day so I'm confident in telling you I know what I am talking about. Regardless, good luck with your problem

[dougyfresh]

Once the eccentric is locked in place that's it, it's done on a new belt (as it was done on mine) and stays in the same position regardless of belt wear.

The eccentric pulley itself stays put but the arm of it that loads up against the gas tensioner moves. This is how the dynamic adjustment is made during engine operation. Without that, the belt will go loose and tight during operation.

Take the gas tensioner off and move that arm on the eccentric pulley. You'll see the timing belt get tight and loose as you move it.

6-10mm is acceptable for normal use. Anything beyond that stresses the gas tensioner and you risk failure of that tensioner.

[Raus]

Maybe I misunderstood you or you may not have understood my response. I have done a few timing belts in my day so I'm confident in telling you I know what I am talking about. Regardless, good luck with your problem

That's all well and good, have you ever done one on the B6, have you seen the tensioner mechanism? From the day you set the tension to the day you remove the belt after 80k miles, that tensioner and that gap will not have moved on anything beyond a microscopic level. How much outer wear are you expecting on a TB and you know they don't stretch? My old belt had only 35k on it, replaced it as a cautionary measure due to a failed guide roller on the tensioner.
Thanks to your help, it's all good now.

[ziggituning]

when I looked up the procedure in the VAG ELSA software it did not mention the measured gap, only to install and rotate 2x, however I have seen the measurement guide on older model audi instructions (2001), and VW, but not on B6. AFAIK.

[Raus]

when I looked up the procedure in the VAG ELSA software it did not mention the measured gap, only to install and rotate 2x, however I have seen the measurement guide on older model audi instructions (2001), and VW, but not on B6. AFAIK.

I used ELSA as well, and yes it does mention to measure the gap for the B6. It specifically says to use an 8mm drill bit (shown in pics as well) to set the gap.
And then it doesn't explain it well, but the gap is supposed to end up within spec (6-10mm) after the rotations. Mine was in spec the first time i set it after the rotations, and ended up being 3mm (way out) after the car ran for a while. 2nd time I set the gap at 8mm again and it ended up at 7mm.

I knew it was ok before I started this thread, just did so to make sure I hadn't misunderstood something. It's all good.