cambelt replacement

[neal]

Hi all,
any recomendations in the midlands ?
Cavendish or zuffenhaus ? Or has anyone done it themselves and interested in a weekend job ?
Thanks Neal

[Crank Case]

Hi all,
any recomendations in the midlands ?
Cavendish or zuffenhaus ? Or has anyone done it themselves and interested in a weekend job ?
Thanks Neal

Bring it up to Jockland - i'll do it.

[Baltic944]

Sorry to interrupt the thread, but should there be a noticeable whine after fitting a new belt(s) ?
Is this considered normal ? Will it go away with sufficient mileage ?

[Crank Case]

Sorry to interrupt the thread, but should there be a noticeable whine after fitting a new belt(s) ?
Is this considered normal ? Will it go away with sufficient mileage ?

The whine can come from incorrect clearance on the balance shaft idler pulley.

Check the Clarke's garage website for the diagram which is clear.

[Baltic944]

Thank you Rob.
Could you answer the questions I posed ? Just to clarify please.
The reason I ask is, having spent upwards of £2500, the previous owner took the car back the next day with concerns about the whine only to be told it was normal following a change of belts. This was less than 1000 miles ago....
Much appreciated.

[tr7v8]

New belts do whine. It diminishes with time & significantly after a 1000 miles or so. If its very noisy then its normally the balance shaft belt which is tight. A correctly adjusted belt is much looser than you'd think.

[Crank Case]

TBH Jim, when I did my belts, I was getting a whine immediately and when I adjusted the clearances to the correct gap, it went silent.
That idler pulley (at the 7 o'clock position in the diagram) AFAIK is to prevent skipping but doesn't need to touch the belt at that point.
The other pulley needs to be correctly positioned (hence both have the offset external nut for this very reason).
I have read numerous threads where they have said 'after a while, it goes away'. This sits uncomfortably with me: IF the belts are okay but still whine a little that's fine but do you then actually know that it's a side effect of new belts or, are they too tight?

It's a pretty straight forward job @Baltic944. As Jim says, it's surprising how 'loose' [for want of a better word] the belts are compared to say, the alternator belt. That one is spooky tight. Were new pulleys installed? Sometimes, a worn pulley bearing can cause whining.

[tr7v8]

In my 944 days I did 3 cambelt changes. 2 very late cars (2.5 & a 2.7) and an early 2.5 auto. The auto was silent when done, but the early cars are very different to the later ones. The 2 later ones were whiny and quietened down once settled. Official Porsche words say check & readjust after a 1000miles, then thereafter at 12K.
All were down with my Krikit (which is made by Gates) and set to Gates numbers. These are different for new & used belts.
Squealing aux belts are pretty common. I adjusted the first with the Krikit and then gave up & used a Mk1 eyeball which has lasted me the 50 odd years of working on engines.

[scam75]

I've found the Conti balance belts always whine a bit even at the right tension. It doesn't go away.

I changed to a Gates balance belt and it is much quieter. If they are set up right they don't need re-tensioned after 1000-1500 miles, I believe this urban myth came about pre auto-tensioner in the series 1 cars.

Stuart

[Crank Case]

I've found the Conti balance belts always whine a bit even at the right tension. It doesn't go away.

I changed to a Gates balance belt and it is much quieter. If they are set up right they don't need re-tensioned after 1000-1500 miles, I believe this urban myth came about pre auto-tensioner in the series 1 cars.

Stuart

Funny, mine are Conti's and are quiet. I did replace all the rollers and pulleys. Having only done 300 miles since 'the big job', seems odd that I may have to consider changing them again next year as I put them in in 2020... Surely they won't have suffered any perishing/ageing?

I shall seek the 'Krikit' belts as the Power steering pump one squeaks like hell near full lock. The alternator belt sometimes.