[ds968]

is this possible ( in theory ) on a 968 and if so has anyone here actually considered replacing the timing belt with a timing chain ? what would that require, and what would be the cons ?

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[flash]

in theory, yes - lubrication would be an issue to be resolved

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[Cloud9...68]

I used to rail against the ridiculously short intervals between belt changes on these engines, but now that Ive done one, I see the job really isn't that difficult, so I can now live in peace with my belts, and the once-every-five-years (at the rate I drive my car) belt change isn't that big a deal. A chain would virtually eliminate the risk of snapping, but at a price of increased noise, and some degree of extra drag vs. a belt.

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[968rz]

Yeah the belts aren't as bad as everyones afraid of, worse I think is the thought in the back of your mind that it could snap at anytime costing lots of $$$.



Paranoia will destroy ya <img src="/forum/images/smilies/968/smile.gif" class="smilie" alt="" />

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[Cloud9...68]

Yeah, the belt (I bought a Gates) I just installed in my car looks and feels pretty bullet-proof. I wouldn't be surprised if the belts available nowadays are much tougher than the ones used in the early 90s at the factory, so I have a feeling the risk of snappage is pretty remote.

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[SILVY968]

how many miles between belt changes does Porsche recommend?

did mine at 110k and now at 165k; 55k miles.

Brian

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[Cloud9...68]

I seem to remember 48K. I've always thought that sounds ridiculously conservative, but apparently there are plenty of examples of these things snapping well before 48K, so some people change them much more frequently; I think I've heard some recommendations as frequent as 24K(!) or two years(!!!). But as I said, I have a feeling the belts of years past must have been of lower quality that what's available today. Also, I suspect premature belt failures have a root cause of some sort, like a roller that froze, a tensioner that went bad, or some other freak event. But of course, given the consequences of breaking one of these things, I guess it's better safe than sorry, especially since replacing belts and rollers isn't really a difficult job once you've done it, though the first time can be a bit daunting.

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[94SilverCab]

I was the unfortunate victim of a snapped balance shaft Belt at 56K...a $5,000 repair...that was just BEFORE I started reading the forums.



For as long as I own this car those belts will be changed every 5years/15,000 miles no matter what!



Cheap insurance in my book,



Jay

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[968rz]

I think the average non-factory mileage advised is about 30k (about 2or3 years), but I could be wrong.

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[ds968]

i would have sworn the manual indicates 60,000 miles intervals for belt changes <img src="/forum/images/smilies/968/huh.gif" class="smilie" alt="" /> which means the belts ( in majority of cases ) are likely to last 120,000 miles,or more this does not mean there won't be some belts that snap at 15k miles, or 30 k miles, and so on, and logically the older they are, the higher the risk, but i'm just saying that manufacturers ( not just Porsche, this seems to be a very common practice across multiple makers ) have a tendency to recommend replacement and/or any other maintenance at twice to three times the frequency than actually necessary ( oil change interval recommendations are probably the biggest scam ). as for belts, no, I'm definitely not willing to test that theory on my 968 and certainly not suggesting anyone else neglects what is obviously " reasonable insurance " in replacing them earlier than the manual indicates, but I'd still like to have seen a chain there so this problem which carries a very high cost potential would be one more thing which one never has to worry about.

btw, in terms of noise I've had many MBZs with timing chains, and with my ear practically resting on the cover it's far quieter than the 968 engine, so not so sure the sound was at all a Porsche consideration - must have been some other compelling reason <img src="/forum/images/smilies/968/dry.gif" class="smilie" alt="" />

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[flash]

it does say 60k - there is also a subsequent recommendation of 45k from the mfg



age plays as much of a role though, as does the manner in which the car is driven - drive hard (autocross, track, etc) and it cuts the interval WAY down

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[Cloud9...68]

I wish there was an inspection that could be done to take the guesswork out of this. When I replaced my belts after five years and about 25K miles, including many trips to the track, they looked indistinguishable from the new ones I put in.

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