Belt tensioner help
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Joined: Mar 2007
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From: UK
Cannot see anything wrong myself but here is the reply from a well respected garage in the UK.
Rich - you have been very observant and spotted a very important issue - but your tensioner is perfectly normal and has just reached its maximum extension at which point it stops moving. This is a dangerous situation as owners assume as it is an automatic tensioner that it will always do the job - which it does not. When the gear type sprockets on the crankshaft and camshaft (that the cam belt runs around) wear they get smaller in the middles and so even a new cam belt can sit too slack on them and the tensioner does not have enough movement to take up the tension (worn rollers and water pump pulley have a similar contributory effect). However the answer is simple if you know anyone with a lathe - you simply pull out (or knock out) the white plastic bung situated on the tensioner arm and replace it with one made to the same dimensions except perhaps 3-5 mm longer on the large diameter to make up the slack lost and enable the tensioner to work in its full range again. If you cannot get one made I could make one for you but at current hourly rates, material costs invoicing and postage - as a one off it would probably cost £50.00 + Vat - which I know is ridiculous for such a small part but we cannot be at work without recovering our costs and so this is inevitable I am afraid. Good luck,
What do you think.
Rich - you have been very observant and spotted a very important issue - but your tensioner is perfectly normal and has just reached its maximum extension at which point it stops moving. This is a dangerous situation as owners assume as it is an automatic tensioner that it will always do the job - which it does not. When the gear type sprockets on the crankshaft and camshaft (that the cam belt runs around) wear they get smaller in the middles and so even a new cam belt can sit too slack on them and the tensioner does not have enough movement to take up the tension (worn rollers and water pump pulley have a similar contributory effect). However the answer is simple if you know anyone with a lathe - you simply pull out (or knock out) the white plastic bung situated on the tensioner arm and replace it with one made to the same dimensions except perhaps 3-5 mm longer on the large diameter to make up the slack lost and enable the tensioner to work in its full range again. If you cannot get one made I could make one for you but at current hourly rates, material costs invoicing and postage - as a one off it would probably cost £50.00 + Vat - which I know is ridiculous for such a small part but we cannot be at work without recovering our costs and so this is inevitable I am afraid. Good luck,
What do you think.
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Joined: Feb 2003
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From: NJ
Never heard that before. Sounds like a band-aid solution anyway. For that price, why not do it right and buy both pulleys. I don't buy it. Also, I have a hard time believing these parts could wear that deep.
It's easy to check. Just take measurements of both pieces. Some should be able to measure pieces to compare.
Raj
It's easy to check. Just take measurements of both pieces. Some should be able to measure pieces to compare.
Raj
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From: UK
Nor me the car has only done 75k miles.
I put the idler pulley on last night which has tightened things up a bit and I think the belt is probably now at roundabout the right tension but the worry is as the belt stretches a little I will not have movement in the hydraulic tensioner to compensate.
One more question - my parts pdf is showing 2 idle rollers for the cam belt 1 for the balance belt - I have 1 for each I guess this is right?
Rich
I put the idler pulley on last night which has tightened things up a bit and I think the belt is probably now at roundabout the right tension but the worry is as the belt stretches a little I will not have movement in the hydraulic tensioner to compensate.
One more question - my parts pdf is showing 2 idle rollers for the cam belt 1 for the balance belt - I have 1 for each I guess this is right?
Rich
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Thread Starter
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Joined: Mar 2007
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From: UK
To be honest if I had gone through the workshop manual process I might not even no I have a potential problem as with the belt on, idler fitted and tensioner on the belt "feels" about right.
Its the fact I know the tensioner is at the end of its travel that concerns me.
Just to be a pain some more if anyone happens to be looking at their belts I'd appreciate if they could measure the distance between the tensioner body and the tensioning arm.
Thanks for all your help guys this forum is great.
Rich
Its the fact I know the tensioner is at the end of its travel that concerns me.
Just to be a pain some more if anyone happens to be looking at their belts I'd appreciate if they could measure the distance between the tensioner body and the tensioning arm.
Thanks for all your help guys this forum is great.
Rich
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From: Boulder, CO
Have you tried rotating the engine a few times?
With this sort of tension system I usually pin the tensioner and install it, put a small prybar on the tensioning lever, then spin the engine over a couple times and recheck the marks before I pull the pin and release the tensioner spring.
Also there are places in the rotation where the belt is pretty slack on the side the tensioner pulls on, rotating the cam to pull on the tensioner when you release the spring might also help.
-Joel.
With this sort of tension system I usually pin the tensioner and install it, put a small prybar on the tensioning lever, then spin the engine over a couple times and recheck the marks before I pull the pin and release the tensioner spring.
Also there are places in the rotation where the belt is pretty slack on the side the tensioner pulls on, rotating the cam to pull on the tensioner when you release the spring might also help.
-Joel.
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Joined: Mar 2007
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From: UK
As soon as I have one it'll be there.
The day I got the car it went in my garage for chain, slippers, belts, rollers and w'pump and hasnt been since.
Should be emerging in the next day or so.
Rich
The day I got the car it went in my garage for chain, slippers, belts, rollers and w'pump and hasnt been since.
Should be emerging in the next day or so.
Rich
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From: NJ
Richy, take a look at this picture. New belts, rollers etc. tensioner is uncompressed. The pin is barely out of the tensioner.
Hope it helps. You could also be a tooth off. Check your TDC on the bottom end and the cam pulley mark. You could be off by a tooth.
Raj
Hope it helps. You could also be a tooth off. Check your TDC on the bottom end and the cam pulley mark. You could be off by a tooth.
Raj
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From: UK
Convinced its not the tensioner - its the position of the arm.
Arm position can only change with a different length belt, different diameter roller or gear.
The issue is marginal, the car is now running fine but I know the tensioner is right on its limit of travel.
I've got to say may be the independant garage over here is right - I can think of no other answer.
Here is my equivalent of the pic above -
[IMG]
[/IMG]
Arm position can only change with a different length belt, different diameter roller or gear.
The issue is marginal, the car is now running fine but I know the tensioner is right on its limit of travel.
I've got to say may be the independant garage over here is right - I can think of no other answer.
Here is my equivalent of the pic above -
[IMG]
[/IMG]