[motomanjack112]

Hello Fellow 968 enthusiasts.



I just purchased a '93 968 Cab with 115k miles on it. Unfortunately, there are no service records with the car, so I don't know when the timing belt was last changed.



If I drive the car and the timing belt fails, what damage will occur or could occur? I apologize for my ignorance but this is my first Porsche.



I sincerely appreciate any help you can provide.



Best regards,







Jack

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[cdtscout]

[quote name='Jack' post='33136' date='Mar 24 2007, 11:05 AM']Hello Fellow 968 enthusiasts.



I just purchased a '93 968 Cab with 115k miles on it. Unfortunately, there are no service records with the car, so I don't know when the timing belt was last changed.



If I drive the car and the timing belt fails, what damage will occur or could occur? I apologize for my ignorance but this is my first Porsche.



I sincerely appreciate any help you can provide.



Best regards,

Jack[/quote]



Jack,

I have owned 3 Porsches (944,944tubo and now a 968)...to be safe, I would have your belts replaced or at least checked ASAP. The belts are not a problem once you establish a baseline (new belts) and keep them serviced. If they fail you could be looking at a major repair expense. I'm sure those more experienced on this board will provide you with more informed details. Enjoy your 968....my favorite.

Craig

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[motomanjack112]

[quote name='cdtscout' post='33137' date='Mar 24 2007, 11:12 AM']Jack,

I have owned 3 Porsches (944,944tubo and now a 968)...to be safe, I would have your belts replaced or at least checked ASAP. The belts are not a problem once you establish a baseline (new belts) and keep them serviced. If they fail you could be looking at a major repair expense. I'm sure those more experienced on this board will provide you with more informed details. Enjoy your 968....my favorite.

Craig[/quote]



Thanks Craig,



I thought this would be the case, but wasn't sure. I had 2 belts fail on Volvos without any damage. (non-turbo motors) Maybe I was just lucky!



Have a great weekend!

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[94SilverCab]

Just to be absolutely clear...



At 56K my Balance Belt went out and with it went the Timing Belt...



The repair was +/- $5K....Head/Valves....etc....



This is a MUST DO service!



BTW, where in PA?



Regards,



Jay

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[Etnier]

The 944/968-series engines are 'interference' engines in that the valves and pistons are capable of occupying the same space. If the timing belt breaks, this is what happens, causing great damage to the valves, pistons and other components.

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[josephsc]

The 968 engine is of "interference" design -- piston goes up high enough so that piston and valve can potentially occupy the same space. It means that when the piston goes up, the valves had better get out of the way, or get crunched. So timing is very critical - mess it up and the valves get bent.



Your Volvo may have been a "non-interference" design -- which means that the valves sit high enough (and piston doesn't go that high) such that they never occupy the same space. Mess up the timing, valves and pistons don't hit.

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[sasilverbullet]

Jack - PLEASE get those belts changed now!!! <img src="/forum/images/smilies/968/smile.gif" class="smilie" alt="" /> <img src="/forum/images/smilies/968/smile.gif" class="smilie" alt="" /> <img src="/forum/images/smilies/968/smile.gif" class="smilie" alt="" />

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[SILVY968]

Previous original owner of my 968 lost a belt while driving at freeway speeds. After $6K in damage and a tow job the whole top of the motor is new. Good for me, very bad for him. From then on I have errored on the side of caution.

Tension the belts at recommended intervals and inspect and replace belts every other time you have tension checked.

"Penny wise and pound foolish"

RUN do not walk to your mechanic before it is too late.

brian

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[ds968]

OT a bit, but why didn't Porsche manufacture these cars with a timing CHAIN ? I heard someone say because chains are noiser..but my MBZ E320 ( timing chain ) engine is 10 times quieter than the 968,s

so that can't be it.. Never needs replacing and essentially no possibility of failure which would cause the massive damage the 968 can suffer from a busted belt. I'm sure there must be a reason, but what ?

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[Darth Vadar]

How could Porsche soak us for belt replacement jobs, adjustments and engine rebuilds @ $6K per, if the darned things never failed?



P L A N N E D O B S O L E S E NC E ...... THE KEY TO A PROFITABLE SERVICE BUSINESS!!!



;>))

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[Dave]

Jack - I've owned an '88 944 and the '92 968. In both cases, I had the belts done as quickly as reasonably possible upon buying the cars. In the case of the 968, I bought it out of state and drove it home. Before departing on the drive from Kansas, I had to satisfy myself that disaster was not imminent.



To do so, you can simply remove a couple of the plastic belt covers on the front of the engine (10mm bolts) and look the belts and their tension over. That was enough for me to jump in the car, set the cruise at ridiculous speed and drive 10 hours or so.



I would recommend taking a peek for yourself right away. It's easier to do than you think. The belt on the 968 is quite a bit wider than the one on my 944 as I recall, which is also reassuring.



Assuming all looks okay, I would (did) drive it only as needed until I could get the belts done and establish a baseline for mileage/time.



Be prepared to watch this little party grow in $$$. It often does truly make sense to do the waterpump, thermostat, and potentially the front engine seals at the same time. These will all need replacement at least once in the life of a 968 by or at this age. The belts and waterpump are kinda required for the "baseline", engine seals if ANY of them are leaking. If they are not, it means that they've either been done already (good) or will leak some time (bad) just due to age.



Why does Porsche use a belt instead of a chain? I have not figured that one out yet and I've read just about every bloody thing on the 944/968 engines available. They did the same thing on the 928 engine. Wish I knew what the engineers were thinking.

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[motomanjack112]

[quote name='94SilverCab' post='33140' date='Mar 24 2007, 11:35 AM']Just to be absolutely clear...



At 56K my Balance Belt went out and with it went the Timing Belt...



The repair was +/- $5K....Head/Valves....etc....



This is a MUST DO service!



BTW, where in PA? I am in Scranton, about 1 1/2 hours north of you.[i]



Regards,



Jay[/quote]



Hi Jay,



It's quite clear after you and the other members chimmed in that I need to do this service item RIGHT AWAY. I don't want to have a $5k plus bill on my hands or destroy a perfectly good engine because of neglect. I suspect that this car was traded into a dealer out on the West Coast probably because it was time to do these services and they would rather get a new car then spend the money on this one. I am going to try to do this repair myself...but only after I find a manual to quide me through it.



Thanks again for your input.



[quote name='Etnier' post='33141' date='Mar 24 2007, 12:13 PM']The 944/968-series engines are 'interference' engines in that the valves and pistons are capable of occupying the same space. If the timing belt breaks, this is what happens, causing great damage to the valves, pistons and other components.[/quote]





Thanks for the explanation.





Jack



[quote name='sasilverbullet' post='33153' date='Mar 24 2007, 03:31 PM']Jack - PLEASE get those belts changed now!!! <img src="/forum/images/smilies/968/smile.gif" class="smilie" alt="" /> <img src="/forum/images/smilies/968/smile.gif" class="smilie" alt="" /> <img src="/forum/images/smilies/968/smile.gif" class="smilie" alt="" />[/quote]



I will Michael...I will! <img src="/forum/images/smilies/968/biggrin.gif" class="smilie" alt="" />



Does anyone have an idea of what a service like this would typically cost?





Jack



[quote name='SILVY968' post='33159' date='Mar 24 2007, 04:30 PM']Previous original owner of my 968 lost a belt while driving at freeway speeds. After $6K in damage and a tow job the whole top of the motor is new. Good for me, very bad for him. From then on I have errored on the side of caution.

Tension the belts at recommended intervals and inspect and replace belts every other time you have tension checked.

"Penny wise and pound foolish"

RUN do not walk to your mechanic before it is too late.

brian[/quote]



Thanks Brian, I will surely have this done right away.



I have to tell you that your Silver Cab looks grrrreat with those wheels. Can you tell me if they are the turbo twists and also what size they are?



Thanks,



Jack

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[motomanjack112]

[quote name='Dave' post='33178' date='Mar 25 2007, 12:39 AM']Jack - I've owned an '88 944 and the '92 968. In both cases, I had the belts done as quickly as reasonably possible upon buying the cars. Do you remember what it cost to have the belt replaced? Also did you replace the pulleys and tensioner at the same time? In the case of the 968, I bought it out of state and drove it home. Before departing on the drive from Kansas, I had to satisfy myself that disaster was not imminent.



To do so, you can simply remove a couple of the plastic belt covers on the front of the engine (10mm bolts) and look the belts and their tension over. That was enough for me to jump in the car, set the cruise at ridiculous speed and drive 10 hours or so.



I would recommend taking a peek for yourself right away. It's easier to do than you think. I will do just that to make sure that I can at least drive the car home or to the shop. The belt on the 968 is quite a bit wider than the one on my 944 as I recall, which is also reassuring.

Assuming all looks okay, I would (did) drive it only as needed until I could get the belts done and establish a baseline for mileage/time.



Be prepared to watch this little party grow in $$$. It often does truly make sense to do the waterpump, thermostat, and potentially the front engine seals at the same time. These will all need replacement at least once in the life of a 968 by or at this age. Since this car was traded with NO service records, I suspect not much was done. Did you do these repairs yourself, or have a Porsche mechanic do them? Also, what kind of cost should I be expecting? The belts and waterpump are kinda required for the "baseline", engine seals if ANY of them are leaking. If they are not, it means that they've either been done already (good) or will leak some time (bad) just due to age.



Why does Porsche use a belt instead of a chain? I have not figured that one out yet and I've read just about every bloody thing on the 944/968 engines available. They did the same thing on the 928 engine. Wish I knew what the engineers were thinking.[/quote]



Thanks again for your help.



Jack

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[Dave]

I've always had the belts done. Although I tackle a lot of stuff on the car, I've chosen to leave the belt and tensioning thereof to very experienced hands.



IIRC, belts (including some or all rollers) is about $600 or so. The new waterpump from Porsche is about $300 alone (add that plus another $100 or so labor for W/P). Seals would likely add a couple hundred more. Yup, that sounds about right, say $1200 to do all the above.



The good news is that you should NEVER have to do the seals again, W/P should last up to about 60k miles, belts at 30k miles or 4 years (whichever comes first). Price for doing the belts should include a "re-tensioning" after 2000 miles. The balance shaft belt in particular will take a wee bit of a stretch by about 2000 miles and then should be quite stable throughout its service life.



Car won't go any faster or nothing fun for the money... but you will sleep much better <img src="/forum/images/smilies/968/wink.gif" class="smilie" alt="" />

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[ether_joe]

Hey Jack, if you are looking at getting a shop to do this for you. I don't know how many members on this board are in the Pennsylvania area, but rennlist.com is overrun with Porsche nuts who could give you a referral to a good shop.



Just put a posting in the 924/944/968 technical forum for a recommendation. I know there are a bunch of nutty guys from Pennsylvania on there.



Also might try the 928 forum.



good luck! Any problems or questions just give a holler.





[quote name='ds968' post='33164' date='Mar 24 2007, 03:06 PM']OT a bit, but why didn't Porsche manufacture these cars with a timing CHAIN ? I heard someone say because chains are noiser..but my MBZ E320 ( timing chain ) engine is 10 times quieter than the 968,s

so that can't be it.. Never needs replacing and essentially no possibility of failure which would cause the massive damage the 968 can suffer from a busted belt. I'm sure there must be a reason, but what ?[/quote]





another reason to swap out for a small block chevy v8 - timing chain!



woohoo! 400hp here I come!

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[motomanjack112]

[quote name='Dave' post='33216' date='Mar 25 2007, 04:36 PM']I've always had the belts done. Although I tackle a lot of stuff on the car, I've chosen to leave the belt and tensioning thereof to very experienced hands. Thanks Dave, I too like to do my own maintenance but I can't find any shop manuals for this car so I may have to leave this job for an experienced Porsche mechanic.

IIRC, belts (including some or all rollers) is about $600 or so. The new waterpump from Porsche is about $300 alone (add that plus another $100 or so labor for W/P). Seals would likely add a couple hundred more. Yup, that sounds about right, say $1200 to do all the above. While I didn't want to have to put another $1,200 into the car right away, it's far cheaper than the alternative.

The good news is that you should NEVER have to do the seals again, W/P should last up to about 60k miles, belts at 30k miles or 4 years (whichever comes first). Price for doing the belts should include a "re-tensioning" after 2000 miles. The balance shaft belt in particular will take a wee bit of a stretch by about 2000 miles and then should be quite stable throughout its service life. Thanks a bunch for your in depth reply. I hope I can find a reasonable shop around me that won't try to soak me for this job.

Car won't go any faster or nothing fun for the money... but you will sleep much better <img src="/forum/images/smilies/968/wink.gif" class="smilie" alt="" />[/quote]

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[flash]

you're in PA - are you close to pete at rs barn? - that would be my first stop

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