924Board.org

Porscheaddiction · Posted: Sun Jul 09, 2006 5:21 am Post subject: Belt changes how often?

Ok guys just had the misfortune of the alt/waterpump snaping the car is fine with a new belt tho.
How often in years and or miles does everyone change their belts?
I would like to eliminate the possibilty of a belt snap from milage/time fatigue.
Chris
_________________
1981 924 NA (Restoring mode)
1984 928S (Enjoying the driving season)

tux · Joined: 02 Jul 2006 Posts: 133 Location: Nottingham UK

Not Porsche specific, but when it comes to timing/cambelts I tend to find the recommended replacement interval and halve it. If the interval is 40000m I will change it out at 20000. Generally not worth the risk, though I am led to believe the 2 litre Audi unit is a "safe" motor? Timewise I would say 24 months is plenty long enough for a rubber belt to serve.
With less critical belts, I tend to go on visual appearance. If they look OK I am prepared to give them the benefit of the doubt.
Just my opinion mind!

_________________
Pete
Merlin Guards Red 1985 N/A

Paul · Posted: Sun Jul 09, 2006 6:21 am Post subject:

On the two liter motors, if you change the timing belt and tensioner every 5 years or 60,000 miles (which ever comes first), you should be fine.

I never reuse a timing belt that's more than 6 months old, if you have to take it off, replace it.
_________________
White 87 924S "Ghost"
Silver 98 986 3.6l 320 HP "Frank N Stein"
White 01 986 "Christine"
Polar Silver 02 996TT. "Turbo"
Owned and repaired 924s since 1977
Porsche: It's not driving, it's therapy.

Porscheaddiction · Posted: Sun Jul 09, 2006 6:22 am Post subject:

not sure how safe it is its, normally yes however if rework has been done to the head its possible are beloved non-inference engine has become interference type.
Thanks for the heads up.
So two years is long enough on the alt/water pump belt?
I keep records of everything I do dates/and work done so thats why the questions on intervals so I can avoid things like this happening again.
Chris.
_________________
1981 924 NA (Restoring mode)
1984 928S (Enjoying the driving season)

Paul · Posted: Sun Jul 09, 2006 6:57 am Post subject:

An alternator belt that's properly adjusted, running on aligned pulleys, and driving an alternator that's not wobbling should easily last 5 years.
_________________
White 87 924S "Ghost"
Silver 98 986 3.6l 320 HP "Frank N Stein"
White 01 986 "Christine"
Polar Silver 02 996TT. "Turbo"
Owned and repaired 924s since 1977
Porsche: It's not driving, it's therapy.

tux · Joined: 02 Jul 2006 Posts: 133 Location: Nottingham UK

I do tend to err on the side of caution! I guess my theories are based on paranoia, but having had several timing belts go on me in the past I just won't risk it! Alternator drive belts etc seem to go at the least opportune moment too so I tend to change them regularly as they are so cheap.
_________________
Pete
Merlin Guards Red 1985 N/A

OutOfTheBox · Joined: 31 Mar 2006 Posts: 434

I beleive that having correctly tensioned belts is more important than their age.

The first motor I rebuilt, I overtightened the NEW cam belt, and it lasted about 2 weeks, when I stopped the car it was a few threads hanging on.

I have also had premature belt failure as a result of "nicks" on the pulleys, and worn alternator mountings.

dpw928 · Joined: 02 Nov 2002 Posts: 1860 Location: owasso, ok 74055

Also, overtightened cam journals can cause premature belt failure. BTDT

Dennis
_________________
81 931 5 sp
78 928 5 sp Silver
78 928 AT Euro Black

Khal · Posted: Mon Jul 10, 2006 7:27 am Post subject:

Mine survived for five years (probably longer, I don't know when it was last changed before we did it). But that's doing ultra-low miles/year.

We've got a good climate for cars, though. And mine was always garaged. Probably helps a bit.
_________________
'80 924 Turbo