Cam belt sounds tight but isn't (but it looks like it was)

[DeeTurbo]

The cam belt is making that noise they make when it's too tight.

I have had the covers off, checked and it seems fine to me. Quarter turn on the longest run, between the cam and HP. 

Same tension on the estate and that sounds fine.

At one stage I thought it was the water pump, replaced and it still sounds the same.

It's now starting to concern me as it's getting louder and there is a vibration that is worst around 2500 rpm. You really notice it on the motorway at 70mph. It's worst in 5th the way the engine is loaded and you can feel it in other gears that why think it's engine related.

The noise from the belt seems to becoming from where the water pump is. There is also a manual tensioner there so I'm now thinking it could be that. What do you think are the chances it's that?

[jjwilde69]

Quarter turn is really hard to judge. I did mine like that and it started to whine like crazy. I backed it off slightly and it went silent. There's a sweet spot I guess you have to find. If you've just done belt then I'd go for that. If its just come on all of a sudden then maybe its something else.

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[C2K]

I had two duff oe water pumps on the rallye.. Fitted an aftermarket part after that..

[jjwilde69]

Also did you loosen the cam wheel bolts to get even tension?

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[welshpug]

have you fitted a belt kit?

[DeeTurbo]

Yes, I loosened the cam bolts. The noise has been there a while now and it not there when cold.

The two pumps where after market and both slightly different so most likely no the same make.

I'll check the idler/manual tensioner and slacken the belt slightly and see how that goes.

It's the vibration that concerns me most. The noise is annoying.

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have you fitted a belt kit?

Belt kit 50k ago with water pump.

Then around 10k ago water pump because I thought it was making the noise and it felt notchy, put another belt on just because I had it off.

[Toms306]

You mean you didn't use the crucial SEEM gauge??

Tbh I'd be tempted just to loosen it a bit. If that doesn't work, try changing the roller. Was it a decent make roller?

[DeeTurbo]

I did start looking on eBay for a SEEM gauge but never got one in the end.

I got a garage to put the kit on so not sure of the quality.

Yeah I'll back it off and see how it goes. I've got a spare manual tensioner so might as well fit it.

Any thoughts on the vibration at 2500rpm?

[Toms306]

Have you got a standard crank pulley? Might be that causing vibrations if so?

Tbh with your mileage it could be something that most of us have never seen fail before!

[DeeTurbo]

Changed the pulley to when I did the belt. Thought it didn't look that true so changed it.

[toseland]

Speak to niall, he is the expert on tight cam belts!

[Toms306]

Changed the pulley to when I did the belt. Thought it didn't look that true so changed it.

Decent pulley? The cheap ones don't last long at all!

[DeeTurbo]

Yeah a patten part but a ECP one. Most I've had have lasted longer then the OE ones. The old one I took off wasn't so bad I'm stick it on and see if there is and difference felt at 2.5k rpm.

[DeeTurbo]

I had a look at this today and I found the belt to be a tad bit looser then I'd like.

I removed the manual tensioner and found that to be dry and there was a bit of play in it. This should have been changed when the kit was replaced by the garage but I've a feeling they didn't change it so it has most likely done 190k!

I bought a manual tensioner by mistake when I was working on the estate instead of the drive belt one but I forgot it at work. Luckily I had the one that was supposed to have been take of my car that the garage gave me back. This one felt and sounded good so stuck it on just to get the car back on the road.

Now I've replaced that it sounds a lot better. I think the power steering pump might be a bit noisy to and there is a bit of dampness around it so it might be weeping so I'll be replacing that tomorrow as I think I should have a spare in the garage.

[DeeTurbo]

I replaced the PS pump and alternator the other week. It's sounding even more better but I was still getting the belt sound on the cambelt when the car was up to temperature.

I slacked the belt off more today and it seems like the noise has now gone. Also the engine sound loads happier and more willing to rev.

Wasn't able to check for the vibration at 2.5k but I think it's still there. The vibration is felt most on the motorway when the engine cruising.

I've got a feeling the vibration might be the HP pump. Might put the old one off the estate on and see how that goes.

[DeeTurbo]

Car feels really good today, especially in traffic and low revs. Before it used to feel jerky but now it feels lighter and smooth.

The vibration at 2.5k is still there so might give another HP pump ago.

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[Poodle]

It's surprising just how slack a cambelt needs to be. What's the theory behnd the hp pump causing vibrations?

[DeeTurbo]

Yeah, the first ever time I did a belt it started slipping off. The second time it slipped off and scrapped the motor. After that I started getting a garage to do them until the last time when they broke my car and left lots of clips off.

I'm thinking the HP pump or vac pump as they haven't been changed recently.

The vac pump has done 330k miles and the HP pump was a used item that was put on around 50k ago and had done around 100k on a previous car.

The vibration I'm getting is felt through the seat of the car mainly at cruising at 70mph, just about over 2.5k.

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[Poodle]

Fair enough. Can you get an assistant to hold the revs at 2.5k and play stethoscope with a screwdriver?

[Toms306]

It's surprising just how slack a cambelt needs to be.

Yeah, the first ever time I did a belt it started slipping off. The second time it slipped off and scrapped the motor.

I'd suggest a bit tighter than that tbh...

[DeeTurbo]

Yeah I'll give that ago.

I was going to swap the vac pump from my girl friends 206 to see what difference that would make today as it's a every easy swap but didn't get chance.

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It's surprising just how slack a cambelt needs to be.

Yeah, the first ever time I did a belt it started slipping off. The second time it slipped off and scrapped the motor.

I'd suggest a bit tighter than that tbh...

It was moving off the pulleys because of it being too tight.

[Toms306]

Crikey, that must've been well overtight then!!

[pug306driver]

So, not having the "seems" unit, how tight is the belt and whats the rule of thumb??

If a small clamp affair was made to clip onto the belt mid run between cam and hp pump, a clip of known length, and a spring gauge ( like a fishing spring gauge to weigh fish?? ) used, how many pounds to deflect the belt say 45degrees, or would that be toooo much deflection??

I would imaging the correct tension would be to illuminate most if not all up and down "play" in the belt mid run??

[mr_fish]

Just done mine at the weekend and went with the general gist of between 90* and 45*

If it makes any difference the tensioner 'square' was nigh on directly under the 13mm bolt.

[Poodle]

You should be able to twist the belt through 90 degrees at that point. Just be a bit savvy with it - if you have hands like Lana Kane and you're having to really force it to reach 90 degrees then it's probably too tight.