Timing belt question

[M. Murphy]

There seems to be an obsession with the timing belts with this car. Is there really a higher failure rate with this engine over others using belts? Is there anyone making a carbon fiber reinforced belt for this application?
Harley Davidson has been using a carbon fiber belt for final drive and has had pretty good success. That is probably a far more harsh environment than a camshaft drive.

[John_AZ]

Obsession?
Hardly.

The main reason the belts fail is lack of owners ability to check the tension and change the belt. The belt whether Contitech or Gates are fine. $12 is cheap insurance to avoid belt damage.

It is not brain surgury, just do it right. If you are not skilled enough to do it without tools, buy them. Home or the Porsche tool P9201 at Pelican
Pelican Parts - Product Information: 000-721-920-10-OEM

If you want a Kevlar belt it is available for $129.
Porsche 944 Racing Timing Belt

John

[v2rocket_aka944]

Belts are to blame like 0.001% of the time. The other 99.999% is due to mistakes on the part of the installer/maintainer in tensioning and checking.

Our belts are made on the same assembly line from the same materials as the 100,000-mile timing belts of Mazdas, Hondas, Fords, etc. It is not the belt to blame.

[GHEN]

I don't think it is a question of the belts having a higher failure rate. It is more that having to do the belts every 35,000 miles, and the fact that if you have someone do it for you means a lot of people put it off or do it themselves improperly.

I put new belts and a new water pump in myself, and then paid someone an hours labor to check the tension with the Porsche tool.


BTW I used the Kevlar belt for my last change.

[nynor]

belt tensioning, etc., is not voodoo with the 944. despite what you may read on many posts here.

it is a belt.

the timing belt requires regular maintenance, including replacement and re-tensioning.

there is a range of acceptable tension. this can be tested in a variety of ways.

PLEASE include your vehicle information in your signature line.

darell

[VirginiaF1]

Originally Posted by nynor

belt tensioning, etc., is not voodoo with the 944. despite what you may read on many posts here.

My PO service records show the following TB mileage intervals dated from 1991 to 2010:

1991 - 43k 43k intv
1995 - 78k 35k intv
2000 - 122k 44k intv
2004 - 171k 49k intv
2010 - 225k 54k intv

The fact that AlfaDoc's went at just 22k kinda makes me obssess... ?

Do trips to the redline affect TB life?
Maybe my 8v had been grannied by the two previous owners: both lady physicians btw

All service records show "genuine Porsche" TB's but no re-tensioning charges..
(I did have the tension done upon my April '11 purchase.)

Curious..

[GHEN]

Originally Posted by VirginiaF1

The fact that AlfaDoc's went at just 22k kinda makes me obssess... ?

NOS belt perhaps? Rubber degrades over time whether or the car or not. That is the primary reason I went with the (kinda pricey) Kevlar belt. Yes it is more money but cheap insurance considering the alternative.

GHEN

[alfadoc]

I no longer have the service records for my '86, as they went to the new owner. But as I recall, that 22K mileage interval also amounted to a 5 or 6 year period of time. The previous owner had the service performed, but the car was being driven very little. I bought it and began driving it every day. I suppose I'll never disregard the time factor again.

I've been putting t-belts on Fiats and Alfas for 20+ years. They both specify 30K mile replacements for their cars, though timing belt longevity was less documented back then. Fact is, the 1967 Fiat Spider was the first production vehicle with a belt. Anyway, the 90° twist method is within my comfort zone on the Porsche. I have a Krikit that came with the car, but don't feel the need for it.

One of my former Alfa 164s that was a daily driver racked up 76K miles on a belt. Come to think of it, I think the one on the Fiat may be at the 20K mile/10 year mark. May be time for a change. I'd never be that cavalier on the 944 though.

[johnkoawood]

Originally Posted by alfadoc

I no longer have the service records for my '86, as they went to the new owner. But as I recall, that 22K mileage interval also amounted to a 5 or 6 year period of time. The previous owner had the service performed, but the car was being driven very little. I bought it and began driving it every day. I suppose I'll never disregard the time factor again.

I've been putting t-belts on Fiats and Alfas for 20+ years. They both specify 30K mile replacements for their cars, though timing belt longevity was less documented back then. Fact is, the 1967 Fiat Spider was the first production vehicle with a belt. Anyway, the 90° twist method is within my comfort zone on the Porsche. I have a Krikit that came with the car, but don't feel the need for it.

One of my former Alfa 164s that was a daily driver racked up 76K miles on a belt. Come to think of it, I think the one on the Fiat may be at the 20K mile/10 year mark. May be time for a change. I'd never be that cavalier on the 944 though.

I too own a Krikit.. that I have never used.. in dozens of belt changes, I have always used, and had no problems with the twist meathod!

[nynor]

Originally Posted by VirginiaF1

My PO service records show the following TB mileage intervals dated from 1991 to 2010:

1991 - 43k 43k intv
1995 - 78k 35k intv
2000 - 122k 44k intv
2004 - 171k 49k intv
2010 - 225k 54k intv

The fact that AlfaDoc's went at just 22k kinda makes me obssess... ?

Do trips to the redline affect TB life?
Maybe my 8v had been grannied by the two previous owners: both lady physicians btw

All service records show "genuine Porsche" TB's but no re-tensioning charges..
(I did have the tension done upon my April '11 purchase.)

Curious..

no idea. my 951 sees redline pretty much every time i take it out. autocross is on sunday. woot!