pete944

If you haven't noticed there have been quite a few 16V cam chain tensioner failures lately. They seem to happen more often with the 944S but the S2 and the 968 are not immune. From reading some of todays posts on the subject it was said that Porsche never specified a service interval for the cam chain tensioner.
Here is my suggested interval that I plan to religiously adhere to. I don't like nasty suprises and would rather replace these parts a little more often and lessen my chances of ever experiencing a catastrophic problem.
My car has all new parts now and if yours doesn't I think it's a good idea to replace them all now and have a good, reliable starting point.

Every 25,000 miles: Timing belt, balance shaft belt, upper chain tensioner pad. Re-tension belts at 1500 miles. I personally like to check the belt tension every 3000 miles.

Every 50,000 miles: Timing belt, balance shaft belt, water pump, all associated roller and idlers, cam chain tensioner. Inspect cam belt spring tensioner and replace if neccessary.

I'll add that it's a good idea to examine the cam chain for wear every time you have the valve cover off and have it replaced if it shows any signs of wear whatsoever.

These intervals are a little sooner than what's normally recommended but I think that it's worth it for the peace of mind. I do my own work so the cost isn't prohibitive, but even if I didn't I would still stick to these intervals.

jonnybgood

Looks good to me. Mine are all fresh so I will be keeping track and do my own work as well.

Jfrahm

I think those numbers are pretty conservative, but I suppose that is what you may want. I feel that if a system is in the car and working properly, it may cause more harm than good replacing it at 1/2 of it's service life. New parts might be bad and contamination or misadventure may occur while you are changing that half worn part.

Personally I do something like this:

Belts every 40K (or 6 years?) retension at 1500 miles and then yearly thereafter. Skip the retension at your peril, they get scary loose after even a few hundred miles on a new belt. if you are not inclined to take it easy for 1500 miles on a new bet you might retension it after 500-750 miles and again at 1500, then leave it until next year.
Replace the water pump every other belt, rollers/seals/etc included.

Replace the top tensioner pad at 100K miles, tensioner (just to get the bottom pad) at 175K or so. I do not think the tensioner will wear out in any finite time but the bottom pad might.

If there is any concern with the chain it could be replaced at that time, but that requires removal of the chain. I would not replace the chain more than once without having the cams replaced or the sprockets reground. Once the cams are out you might as well freshen up the head, so I'd be inclined to push that whole tensioner/chain/cams/etc. project out to around 200K and and just do the whole head, and what the heck you might as well do the rings and bearings while you are at it. It'll probably need engine mounts anyway so the crossmember will be off. If this were my plan I'd probably start thinking about tossing another top pad in there at 160K or so and see how it goes. If it makes it to 240K without a top end, throw it a party, then decide to do a rebuild or just drive it into the ground.

It would also be wise to replace the fuel lines at or around 100K or 15 years. These lines do not age well and engine fires are getting to be quite common. Any smaller lines as well (if equipped) not just the mains. Also you might as well rebuild the injectors or at least reseal them at this time, and replace the fuel filter.

Replace the coolant every few years, I can't believe how many head gaskets, thermostats and water pumps get wrecked because people don't change their coolant. Extended life? I don't think so. A good wet shop vac makes changing coolant amazingly easy.

Plugs, wires, etc. That's really up to you. I like to pull the plugs every few years to see how they are looking. I use copper plugs so the cost is trivial. The lifespan of the wires, cap, etc. I cannot easily judge but I'd like to think you could get 50-60K out of them.

For what it's worth I am reevaluating my frequency of oil changes. Some studies are suggesting engine wear is reduced after oil has gone beyond 3000 miles. I have generally changed my oil every 4000 miles or so, filters every other change, but given the quality of the products it might not be bad to leave it in longer, at least on a street car. 8000 miles or yearly might be just about right for me. On older engines that are getting some blowby contamination of the oil, it might be better to change it more often though. If your oil smells of fuel I would not leave it in there too long.

-Joel.

josephsc

I personally have added the following to my schedule.

Everytime you read about a failure on Rennlist: inspect.

pete944

I realize the intervals are a little short but I like messing with the car and I'd rather pay a little now instead of a lot later.
As far as oil I've heard that 7500 miles is ok but I still prefer to change the oil & filter every 3000 miles. I change the coolant once a year.

Dal Heger

Replace the timing belt every 30k miles or so
Replace the top chain tensioner pad at 90k miles (three timing belt changes) - might want to just replace the entire tensioner.
Re-tension the timing belt at 1500 miles after replacement, every 15k miles thereafter.
Replace the timing chain at 200k miles
Replace all the timing belt tensioners/idlers every timing belt change.
Replace the water pump every second timing belt change.

That should be good.

Dal.

Luis de Prat

Good initiative, 944Pete!

If you do pull the cam cover, check the condition of the rubber gasket. If it's rock hard, you may want to replace it to avoid leakage onto the exhaust headers.

When replacing the cam cover, be very careful not to overtighten the allen head bolts, as they strip easily. Tighten with a torque wrench to no more than 7 ft/lbs or 10 Nm.

pete944

You're right, that should be good. The operative word is should.
There seems to be a lot of these motors grenading themselves lately and I don't want to join that group.
The pads are cheap enough to change at every belt change.
The tensioner at $300 works out to .006 cents per mile if it's changed at 50K miles.
I think it's a small price if it prevents a major top end disaster.