TheoJ

and there it was again... in another thread: 4-5 years of service: TB replacement !! (or if the mileage of 60k miles was reached)

Is there any document from Porsche that actually says so? I have a feeling that 5 yers is a good time to replace but never found any formal instruction about this. Anyone?

regards

jon928se

How timely.

My 90 GT has done very few miles or kiometres since the last TB change 4.5 years ago. It's about ready for the tension check at 1500 miles ?!?

I have the TB I took off 4.5 years ago - it still looks like I could put it back on. Go figure

jmrjames

This TB thing seems weird to me. I wonder if this is a design flaw or some sort of plot. Are there any other cars (Not Porsche) that requires this much attention to a Timing issue ?

Just a stupid question.

WallyP

This was thrashed out pretty throughly several years ago on the Forum.

Consensus at that time seemed to be:
- There is no Porsche recommendation other than 60,000 mile replacement.
- Porsche expected us to drive the damn things, so 60,000 miles would be 5-10 years at most.
- The belt ages due to heat, oil and ozone, in addition to mileage wear.
- Given the cost of repairs if the belt fails on interference models, better safe than sorry. Five years or 50,000 miles seemed reasonable.

Still would seem reasonable, but I suspect that we over-do the caution. The chorus of cries to replace the belt on a very low-mileage GTS in the Middle East is an example. It might be safer to leave that belt on, rather than have a very inexperienced shop learn how to change a belt on your car...

Gary Knox

On my first 928 - an '87 S4 with 50K on it when I bought it in 1999 had never had the belt changed. I was a "novice" with respect to 928's at the time, but had an Audi V8 with almost the same cam drive belt system. The factory spec on that car was to change the belt at 90K miles.
So - I drove the 928 for 2 years before I discovered 928 Owners Club, and learned of all the knowledge available from other & long time owners. I promptly had the belt changed AT 14 years and 80K miles. Of course it was a Porsche belt, not an aftermarket one. But - I now seem to change whenever I buy a car that is new to me, and at about 50K miles or 5 years. I DO think we are a bit paranoid, but as Wally says - a bad belt is a bad problem.

Gary Knox

StratfordShark

My nephew just wrote off engine in his Alfa 156 when TB failed. I think he had skipped the regular change interval...

jmrjames

Thank you for the information. I believe the nutshell answer saved me a lot of searching.

I have been used to chains and spokes that provided this function. It seems that this set up requires less attention.

Another dumb question, Are all years of the 928 interference models ?

Landseer

Its not just about the belt. Lots of other stuff in there that needs review. I'm figuring to disassemble and reinspect these 32V cars at least once in 18 months, ongoing.

WallyP

"I have been used to chains and spokes that provided this function. It seems that this set up requires less attention."
I had a timing chain system failure on a Jag six-cylinder.

All 32-valve engines are definitely interference.

Early 16-valve engines are almost certainly non-interference.
Later 16-valve engines are usually non-interference, but have been shown to be interference in some cases.

IrishLegend

I thought it was like this?

'78 - '84 = non-interference
'85 - '95 = interference

Is this wrong?

Porscheaddiction

Check out some of the Ferrari forums and you will see Porsche is not the only ones with this sort of attention requirement on TB.

WallyP

You can get a lot of loud arguments...

The way that I stated it is my best assessment of the question.

We have had posts where members stated flatly that they have had valve crashes on 16-valve engines.

rluvsporsche

My experience with 110,000 mile I've only replaced the belt 2 times. I prefer to follow Porsche recommendation. IMHO, if 60K is good enough for Porsche then its good enough for me.

Mrmerlin

not only does the belt get replaced, so does the tensioner roller, the pivot bushings and the pivot bolt, and the tensioner gasket and boot at a minimum

Vilhuer

At current rate it takes me 48 years to get to 60k miles on automatic GTS. Should I use belt I changed last year until 2057?