924Board.org

[johny42]

I just finished putting the new head on. I also decided to put on a new timing belt. It seemed prudent. However, I seem to have a lot of timing belt noise. Loud enough that I can hear it when the hood is closed. It sounds like I'm running a blower. I checked the alt belt and hit it with belt dressing to make sure it is the timing belt that is making the noise.

Is this normal with a new belt? I've never changed one before. It is certainly louder than on my '80. I set the tension according to Haynes, just able to turn it 90deg by hand. However, I'm not a small guy and I wondered if my "just can do it" is the same as others? Anyway, any help? Am I in danger of busting the thing and ruining another head?

TIA

John
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Johny
80 931 (all in boxes)
82 931 - making me crazy
84 928S - leaking radiator
86 951 with cam off

[924RACR]

I'm not sure, but can't help wondering, is it tensioned too tight? Perhaps more likely even, did you replace the tensioner? When dead, those'll whine, might be taken to sound like a blower.

It's a fairly inexpensive part (like the belt, it's a VW/Audi part), and I do recommend replacing it at some point, as the bearings do go.
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Vaughan Scott
Webmeister
'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype

[Smoothie]

Yeah that, "just able to turn it 90deg by hand" isn't too scientific.

If it's the '82, I'd guess you have the later, stronger designed tensioner with the seam down the middle like I had, but I'd definitely replace it anyway. The wheel itself is stronger, but the bearings can't be much if any better. I'm all happy and lucky over here that I got mine replaced recently. If it and/or the belt fails, a nasty fight between the valves and the pistons will ensue. Your loud noise is likely from the belt being too tight - and obviously that'll shorten the life of both the belt and tensioner.

When I replaced my belt and tensioner, once the belt was on and tensioned to where I thought it should be, and tensioner bolt tightened... before reattaching the belts to the alternator and ac compressor, I start the car and let it run breifly just to make sure the belt isn't too tight as evidenced by a loud screaming sound from it. Then I readjust it if necessary, try again, then reattach the other belts. (Leaving the other belts off is mainly to allow easy access to the tensioner, but incidentally also eliminates any noise from them.)
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"..it's made in Germany. You know the Germans always make good stuff."


'82 924T, US version, dark green metallic, 5 speed Audi 016G gearbox

[CMXXXI]

Yes, I agree that "the 90* test" isn't very scientific. I'd loosen it just a smidgen and see if the noise changes or goes away. I just rebuilt my engine and installed a new belt and tensioner (it failed leaving me with bent valves) and I'm getting a little more (or different) noise than before. I suspect that some difference is attributed to the new belt, the teeth on it will have to get "broken in".
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'79 Eurospec 931

[numbbers]

Well guys, I just replaced my water pump, and of course did the timing belt at the same time. This is my third belt replacement, and I did the regular 90 degree test/adjustment. Put everything back together, and sure enough, noise. Just like Vaughan recommends, I went back in and lossened the belt about a tenth of a turn on the adjuster pulley, and all mis back to normal.
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1980 924 Turbo

[johny42]

Well, to close out my issue: I changed out the tension pully and reinstalled the belt last night. Quit as a wisper. Now, what is all that cam noise I'm hearing? Anyway, I set the belt a little looser as well.

I did spring for the $26 for the EMPI adjustment tool. Makes it easier than levering the small plus screwdriver like I did before.

Cheers for the board and all your help.

John
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Johny
80 931 (all in boxes)
82 931 - making me crazy
84 928S - leaking radiator
86 951 with cam off