[RKDinOKC]

This might be interesting to some of you 944 guys...One of the other decisions I made on the GTS rebuild was to keep the stock timing belt tensioner. There is one everyone is going to made from an Audi belt tensioner.

With the stock tensioner the belt tension needs to be periodically checked and re-adjusted as the belt stretches over time. Porsche says once after 2000 miles with a new belt, and then after 40,000 miles. With the Audi tensioner the same tension is maintained as the belt stretches. So, the belt only needs to be checked periodically for wear and never needs re-adjusted.

On the 928 the stock tensioner has a contact that triggers a dash warning that the timing belt is getting loose. It is pretty sensitive so depending on the age of the belt and how many times it has been re-tensioned you can typically take it easy and make it to a garage to get the belt re-tensioned or replaced. Because the Audi tensioner would only have too much slack if the belt had already broke there is no loose belt warning.

Not long after I got the GTS my toothed belt waring light came on. The belt had been replaced just 2000 miles before I got the car. The warning went off while I was sitting in a McDonalds drive-thru just idling. Mechanic found the belt needed tensioning AND the bolts holding the tensioner on were loosening. He rebuilt the tensioner and I had no more warnings.

The next time my toothed belt warning came on I was road tripping at high speed. Right after lifting off the accelerator to slow down from 140mph the light came on. I pulled over immediately and called two mechanics. The one the rebuilt the tensioner, and one that was only 30 miles from my current location. They had me start the car and let it idle for 10 minutes and agreed that if the light did not come back on to drive to the closest mechanic and have him check it out. There is some kind of loop in the warning system that the light will come back on after 3 minutes if the problem persists.

Got to the mechanic with no more warnings. He pulled the timing belt covers, checked the belt tension, and inspected everything you usually would like the water pump, rollers, etc. The tension was correct and he could find nothing. For good measure he replaced the connector on the wire going to the tensioner sensor. Didn't have any more warnings for another 2000 miles which included auto crossing and high speed driving.

The next time the waring came on was the same situation where I had lifted from over 140mph on the highway. Was more than half way to Dallas where the mechanic was that checked it before so called him. He said to just take it easy and bring it to his house. Well the light came on a couple more times when I lifted, then bang and the valve crash.

Inspecting the carnage we found the end of the cam had sheared off where the keyway is for the hub that is used to adjust the timing gear before tightening it down. One of the prongs on the hub was broken off and gone. There was a line of rust on the back of the timing gear where the hub prong had evidently been cracked for some time before it loosened enough to wear the keyway and break. Everyone I talked to said it the hub prong cracking and breaking was a defective part that just broke.

The really interesting part is that the timing belt warning was telling that there was something wrong. Just that nobody knew to check that timing gear adjustment hub. Evidently the hub loosening from the crack in the part was causing a vibration that was being picked up by the timing belt and setting off the warning. It had nothing to do with the looseness of the belt. Having that warning, even though not able to find the problem at the time is why I decided to keep the stock tensioner.

If that thing goes off now and the belt is still the proper tension, the whole front of the motor is coming apart and getting inspected!