ltc

Was going thru the service records of the 968 and saw that after the timing and balance belts were replaced at the (Porsche) dealer, the invoice stated that unless the car was returned in 1200-1500 miles for retentioning, the warranty would be void?

Is this normal/typical?
Is the warranty mentioned a warranty against damage if the timing belt broke after replacement if it wasn't returned for retentioning?
(IIRC, you can break a balance belt and it's not fatal to the engine).

Sorry for a newbie question, I've still got a lot to learn about these cars.

flash968

the retensioning of the balance belt is essential for a number of reasons, not the least of which is the damage that vibrations, which can occur as a result of jumping a tooth, can do to the rest of the components, like the oil pickup tube

User 41221

To answer your questions...

1) Yes, it is normal and very much required. The new belts will stretch and need to be reset after initial break in, at which time they tend to be quite stable within the service period.

2) I am guessing they will interpret the warranty to their best advantage, but yes, if you do not return for the retension, I am sure they will void any warranty associated with it.

3) Yes, you can potentially break a balance shaft belt and not suffer any damage, but if that happens to you, go out a buy a lottery ticket while you are at it. The balance shaft belt runs in close proximity to the timing belt and will most likely get tangled up with it causing it to break as well. Running without a balance shaft belt is a bad idea, as what flash was referring to with the oil pickup tube cracking can result.

Its not likely that you will either skip a tooth or get a vibration bad enough to crack your oil pick up tube. If you are loose enough to skip one tooth, you will probably skip more than one and wind up hating life shortly afterwards.

Keep your belts serviced properly and you should be plenty safe.

Regards,

Shamus

I'm sure you are aware, but it's worth saying the 968 is an interference engine - a broken timing belt likely results in severe engine damage when the pistons and valves collide

RajDatta

The retension is normally part of the belt change price so the only hassle for you is the 1-2 hrs you have to spend for peace of mind. Its a no brainer and plenty have paid the price for not doing this. These belts are essential in your 968 running properly.
Raj

Gary Grigsby

Don't neglect the Balance Shft belts! The big 4 cylinder in these cars creates significant vibration and subsequent vibration related part failures-I've feel like my car has had them all-be attentive to the balance shaft belt maintenance! BTW, I've had the BALANCE belts break, and still run the car in competition conditions without initial problems-no TIMING belt issues occurred. To replace the belt on the 968 (1995), the crank pulley must be removed-so you need a flywheel lock as well. THe belts need to be aligned properly-there are demarcations on the upper and lower pulleys that are used to line the belts up when the engine is at top dead center. The job can be done at the track, with the proper tools, if you can align the motor and the pulley(s) correctly.
Gary

ltc

Thanks everyone.
Shamus, no I didn't know it was an intereference engine...I just heard bad things happen if the belts break. I've got a LOT of reading to do over the winter.
Raj, I am mechanically challenged. Any work on the cars is left up to my mechanic (wrenching for my son's kart is the limit of my mechanical abilities)

RajDatta

ITC , we will just have to bring you up to speed. Its nothing more complex than your son's kart. Don't be intimidated, its just nuts and bolts.
Raj

ltc

I appreciate that. But please understand I am mechanically challenged...besides my mechanic likes the sound of "whatever it needs" whenever I drop off one of the cars.
I do look forward to learning more about these cars.