[Normy]

The "Gilmer" belt used in our cars was picked over chains because they are quieter, lighter, and they can also be used to drive things such as the oil and water pumps. This made the engine shorter as well. Also, belts require no lubrication- making the engine somewhat cheaper to build since lubrication sprays and extra oil gaskets were not required. I think I read all this in "Project 928".

The Gilmer belt is very typical '70's German/European construction technique. VW finally quit using these in their 1.8 and 2.0 liter four cylinder engines recently, but Ferarri continues to use them to this day.

I suspect that a timing belt could be produced that would last the life of the car, but it would require much stouter construction than is currently available. Belts don't "break". These things are similar to the drive belts on Harley-Davidson motorcycles, and have kevlar fibers embedded in the rubber to give tensile strength and they are very strong. The typical failure mode of a Gilmer belt involves the engine either skipping a tooth or two due to looseness, or several teeth being sheared off altogether upon startup, allowing the crank to skip forward. The teeth are nothing more than rubber bumps along one side of the belt. When they get old and dried out...these bumps can simply be ripped off. The solution is a belt that is wider, or two belts working as a team, or kevlar loops within the teeth themselves that prevent them from being sheared.

-I think [?] the general consensus on this board and Reutterwerk and Rennlist is that the "Porkensioner" that Ken sells over on Liftbars.com is probably a vast improvement over the factory tensioner, and this part would allow the belt to remain serviceable for a far longer period of time.

As long as it is changed every 45k miles [and done correctly], the timing belt is every bit as safe as a chain or a set of [noisy] gears. Let it go, however, and you now have a cobra under your hood waiting to bite...your wallet!

N!