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Hey all,

over the weekend i did a major service on my r33 rb25det, changed the water pump and put a Gates high performance timing belt kit (yes i changed the idler and tensioner etc)

Now when my car gets hot it makes a slight whirring sound..

i have read many topics which say the belt is too tight, others say that the Gates performance belts make this noise because they are a hard composite material..

What are other peoples suggestions? Does anyone have this timing belt kit (blue belt) and have no noise?


If so, can i adjust the idler without taking the bloody balancer off again?


Cheers

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https://www.sau.com.au/forums/topic/444746-gates-timing-belt-whirring-noise/
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My gates belt is fine. And have to agree I wouldnt try and do it without pulling the covers off properly.

I tried to do something with the bottom cover after I'd put my balancer on and it just wouldnt happen. Luckily for me it was only something minor and cosmetic so I just got over it, but yeah its not really possible to pull it off on an engine stand let alone in the car.

Yes this topic has been discussed countless times and it's always the same reply, incorrect tension.

Set the tension correctly and your belt will run as silently as a stock belt.

Set it too tight and once the engine's hot, the belt is over tensioned.

That's the idler bearing you can hear complaining, noise will reduce once the bearing tolerances increase.

I saw this mod on the GTROC forum.

Would still be a finicky operation and totally unnecessary if the owner had used a Nissan belt.

post-73571-0-06277300-1403469542_thumb.jpg

Mine has always made that noise with the old Nissan belt then with the new belt, a mechanic friend dripped some water over the belt while it was running and it went silent so Ive

been bit confused about where the noise comes from.

How can you know if you have the right tension, is there a special tool for measuring it?

Edited by AngryRB

The Gates belts are Kevlar, which won't stretch much, if at all. As the block expands with heat it needs to either stretch a little or be run a little slack when cold. I would prefer to just run the Nissan belt.

  • Like 1

to give the SAU mechanics a bit more info to go on id recommend you get your phone and make a video of

1: the noise (which can help determine if it is the belt or the idler).

2: take off the cam cover and video yourself manually twisting the belt by hand to show us how much tension is on it.

Bottom line is that noises from cam belts are common and most likely nothing to worry about. But if indeed it is too tight, then you need to worry about it...

Some posters are missing the point.

If the belt runs silently when the engine's cold, then becomes noisy once at operating temp., something's wrong…...

Too tight.

What astounds me is that after years of discussion about noisy belts, growling idler bearings etc, a topic like this is still posted.

It's old news. Just do the job right.

Some posters are missing the point.

If the belt runs silently when the engine's cold, then becomes noisy once at operating temp., something's wrong…...

Too tight.

What astounds me is that after years of discussion about noisy belts, growling idler bearings etc, a topic like this is still posted.

It's old news. Just do the job right.

maybe, maybe not. This has always been the fact with the timing belt noises. You cant say for certain without a bit of testing that it is or isn't a problem. i.e. that it is or isn't just belt noise or noise from incorrect tension.

Had my Gates racing belt put on 10,000km ago. Still whines slightly when warm. Belt was put on by a very well known garage in Sydney (lots of love for the workshop here on SAU too)

Had many knowledgable mechanics say they are slightly noisier than normal belts (and trust them over joe blo in the interwebs)

Unsure if the Joe Blow reference was directed at me, couldn't really care but I will offer some insight for those interested.

I've experimented with belt tension a fair bit, a lot more I'd hazard than any workshop where the obvious criteria is to get the vehicle serviced and out.

I fitted up belts and ran the vehicle at operating temp with NO bottom belt cover. Continually did tension checks as well as monitoring the harmonics these strange 4-pulley systems generate.

Can honestly say I've only read of one other owner who has also gone to this much effort and it is a lot of work.

But I'm 64, retired and have time on my hands for such investigations.

Yes I got Gates belts to run silently, but as I said ages back, they're simply not worth all the hassle. Unless one is doing this work on a daily basis, you will forget the exact tension required. Job then has to be done twice.

Yes a brand new idler will groan if belt tension is too tight. Slacken the belt slightly and the noise disappears.

This is idler noise, not tensioner which I've never had make a noise as it's on the slack side of the belt.

If a tensioner groans, you're so far over tensioned it's ready to snap the idler stud.

All these noises are so easy to pin point with the covers removed, no guesswork at all.

  • Like 2

Unsure if the Joe Blow reference was directed at me, couldn't really care but I will offer some insight for those interested.

I've experimented with belt tension a fair bit, a lot more I'd hazard than any workshop where the obvious criteria is to get the vehicle serviced and out.

I fitted up belts and ran the vehicle at operating temp with NO bottom belt cover. Continually did tension checks as well as monitoring the harmonics these strange 4-pulley systems generate.

Can honestly say I've only read of one other owner who has also gone to this much effort and it is a lot of work.

But I'm 64, retired and have time on my hands for such investigations.

Yes I got Gates belts to run silently, but as I said ages back, they're simply not worth all the hassle. Unless one is doing this work on a daily basis, you will forget the exact tension required. Job then has to be done twice.

Yes a brand new idler will groan if belt tension is too tight. Slacken the belt slightly and the noise disappears.

This is idler noise, not tensioner which I've never had make a noise as it's on the slack side of the belt.

If a tensioner groans, you're so far over tensioned it's ready to snap the idler stud.

All these noises are so easy to pin point with the covers removed, no guesswork at all.

Wasn't directed at you at all. Just meant it in a non dscriptive sense.

  • 3 weeks later...

I've experimented with belt tension a fair bit, a lot more I'd hazard than any workshop where the obvious criteria is to get the vehicle serviced and out.

With all due respect Sir there are many workshops that will only use gates belts that whine their whole life and they stand by their products and services and have had no failures in drag, track, and street cars hundreds upon hundreds of times over. And furthermore would be more than happy to rebuild an engine if they did. Just saying that not all of them have the criteria you suggest. Reputation has a lot to do with it. Edited by XGTRX

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