Timing Belt
06-08-2016, 11:07 PM
#2
Nordschleife Master
The factory recommends checking tension at something like 500 miles.. as the initial install will stretch slightly as belt wears in.
My experience of waiting until the timing light came on (cold engine and higher rpms) was that the light came on at 1400kms (new Gates non-racing belt), and after that initial re-tension, its been fine for years and thousands of miles since.
My experience of waiting until the timing light came on (cold engine and higher rpms) was that the light came on at 1400kms (new Gates non-racing belt), and after that initial re-tension, its been fine for years and thousands of miles since.
06-09-2016, 11:30 AM
#5
Chronic Tool Dropper
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Access for adjustment on the S4 requires that the right side (passenger side on US cars, driver's side on UK/JP/AU cars) distributor cap and cam belt cover sections be removed for access to the belt.
Tension gauge options include the factory tool ($$$), and also a third-party tool called the Kempf Tool, available from our US 928 parts vendors. You may be able to borrow one from another local owner.
06-09-2016, 04:56 PM
#6
Former Vendor
The following applies only with a Factory Porsche timing belt, or a Gates replacement:
Note: This information can not be found in any factory publication. This information is the result of 30 years of working on these cars and from literally hundreds and hundreds of belt changes.
The factory service interval for adjustment after a new belt is 2,000-2,500 miles. Any sooner than 2,000 miles and you will have to do it again, as the belt has not completely stretched. After this first adjustment, it is a good idea to re-adjust the belt every 15,000 miles....although it will not change as dramatically as it does in those first 2,000 miles.
The belt warning light, regardless of what people on the Internet (and this Forum) say, is extremely accurate, extremely consistent from car to car, and works extremely well. This is, without any doubt, one of the great features of the 928 models.
If you set the belt to 5.0 on the Porsche tool, the warning light will never come on during this interval...unless there is something wrong with how the job was performed. (At 2,000-2,500 miles the tension will have backed down to right at 3.8 on the Porsche tool. The warning light does not come on until the belt is at 3.0-3.2.)
When the belt warning light does activate, from a belt getting down into the 3.0-3.2 range, it will always light as you de-accelerate the engine....the most widely reported timing for this happening is when the car is coming off the freeway and de-accelerating on the off ramp. You can confirm this by simply confirming the water temperature is normal, shutting the car off, and re-starting it. The belt light should not come back on. If this happens, don't panic. Make an appointment to have your belt readjusted (or adjust it yourself, if you have the proper tools.)
If this varies from any way, as described above....the light comes on again after restarting the car....it comes on when not de-accelerating, the water temperature is abnormally high, you do have a reason to be very concerned. I would not restart the car, a second time, until the belt was inspected.
Note: This information can not be found in any factory publication. This information is the result of 30 years of working on these cars and from literally hundreds and hundreds of belt changes.
The factory service interval for adjustment after a new belt is 2,000-2,500 miles. Any sooner than 2,000 miles and you will have to do it again, as the belt has not completely stretched. After this first adjustment, it is a good idea to re-adjust the belt every 15,000 miles....although it will not change as dramatically as it does in those first 2,000 miles.
The belt warning light, regardless of what people on the Internet (and this Forum) say, is extremely accurate, extremely consistent from car to car, and works extremely well. This is, without any doubt, one of the great features of the 928 models.
If you set the belt to 5.0 on the Porsche tool, the warning light will never come on during this interval...unless there is something wrong with how the job was performed. (At 2,000-2,500 miles the tension will have backed down to right at 3.8 on the Porsche tool. The warning light does not come on until the belt is at 3.0-3.2.)
When the belt warning light does activate, from a belt getting down into the 3.0-3.2 range, it will always light as you de-accelerate the engine....the most widely reported timing for this happening is when the car is coming off the freeway and de-accelerating on the off ramp. You can confirm this by simply confirming the water temperature is normal, shutting the car off, and re-starting it. The belt light should not come back on. If this happens, don't panic. Make an appointment to have your belt readjusted (or adjust it yourself, if you have the proper tools.)
If this varies from any way, as described above....the light comes on again after restarting the car....it comes on when not de-accelerating, the water temperature is abnormally high, you do have a reason to be very concerned. I would not restart the car, a second time, until the belt was inspected.
06-09-2016, 06:17 PM
#7
Rennlist Member
ive done quite a few of those. all with non-gates belts. i run them for about 1000 miles and then check the tension. mine, and others included are all at about 4 on the porsche tool at this retest. usually a flat on the tensioner bolt is all that is needed to bring into spec and that doesnt change for many many miles . usually for me, thats 2-3 race seasons.
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06-09-2016, 08:06 PM
#8
Three Wheelin'
My experience with the S3's warning circuit was that it is pretty finnicky and for someone who doesn't have a lot of experience with the system can cause sheer terror every time it gets tripped. The OE copper strap is fragile and if it breaks can only be replaced by removing the belt (replace it with the wire version at the first opportunity) and the spade connector to the wire that goes through center cover is extremely sensitive to orientation - get it wrong and the connector can rub against the center cover causing intermittent warnings - this particular issue caused Bill Ball and I many hours of tail chasing before it was finally discovered.
06-10-2016, 12:06 PM
#11
Rennlist Member
My experience with the S3's warning circuit was that it is pretty finnicky and for someone who doesn't have a lot of experience with the system can cause sheer terror every time it gets tripped. The OE copper strap is fragile and if it breaks can only be replaced by removing the belt (replace it with the wire version at the first opportunity) and the spade connector to the wire that goes through center cover is extremely sensitive to orientation - get it wrong and the connector can rub against the center cover causing intermittent warnings - this particular issue caused Bill Ball and I many hours of tail chasing before it was finally discovered.
06-10-2016, 03:58 PM
#12
Captain Obvious
Super User
Super User
I had the same experience with mine. I had the wire break, so i had to solder it to the wire loom (the part that is wired the male plug that plugs into the timing belt cover ) but it kept giving a warning , even though the tension was to spec. i cleaned up the connections and made sure the spade connection was tight, i replaced the cover plug receptacle too, yet the problem continued. so, i just removed it and did the "peak hole" in the cover to check gross tension. seems to work. i can detect if the tension is at about 3, no problem (and thats without removing the covers)
Never had a problem with mine and I had it apart a few times.
06-10-2016, 04:16 PM
#13
Former Vendor
My experience with the S3's warning circuit was that it is pretty finnicky and for someone who doesn't have a lot of experience with the system can cause sheer terror every time it gets tripped. The OE copper strap is fragile and if it breaks can only be replaced by removing the belt (replace it with the wire version at the first opportunity) and the spade connector to the wire that goes through center cover is extremely sensitive to orientation - get it wrong and the connector can rub against the center cover causing intermittent warnings - this particular issue caused Bill Ball and I many hours of tail chasing before it was finally discovered.
I don't even bother replacing the copper strip, if it is intact....there is no force on it, once assembled.
06-10-2016, 11:53 PM
#14
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The only thing I can add is that after about 6 months, even if you haven't driven 2000-2500 miles (but at least some), the belt will likely have done its run-in if it's subjected to temperature swings (i.e. a non-climate controlled garage.) If it's stored in a climate-controlled garage then all bets on mileage and time are off.
(My 928 population has a disproportionate number of 'garage queens' that see < 1000 miles per year.)
06-16-2016, 11:37 PM
#15
Even though my sample number of belt changes is about 1/50th, or less, of Greg's, this is exactly what I have observed also.
The only thing I can add is that after about 6 months, even if you haven't driven 2000-2500 miles (but at least some), the belt will likely have done its run-in if it's subjected to temperature swings (i.e. a non-climate controlled garage.) If it's stored in a climate-controlled garage then all bets on mileage and time are off.
(My 928 population has a disproportionate number of 'garage queens' that see < 1000 miles per year.)
The only thing I can add is that after about 6 months, even if you haven't driven 2000-2500 miles (but at least some), the belt will likely have done its run-in if it's subjected to temperature swings (i.e. a non-climate controlled garage.) If it's stored in a climate-controlled garage then all bets on mileage and time are off.
(My 928 population has a disproportionate number of 'garage queens' that see < 1000 miles per year.)