The benefits of a rubber timing belt.

Dear Car Talk

Dear Car Talk | Jun 01, 1991

Dear Tom and Ray:

I notice that a lot of new cars are now coming out with rubber timing belts instead of metal timing chains. These rubber belts have to be changed periodically at no small expense. Other than ripping off the consumer, is there any valid reason for this change to rubber belts?

RAY: Sure there are. For many years, metal timing chains worked fine. Except for the fact that they were noisy and expensive to repair when they did break, no one ever complained about them. They did what they were supposed to and generally lasted about 100,000 miles.

TOM: But then came overhead cam engines. When the cam shaft is on top of the engine instead of in it's traditional place--in the middle--the chain has to be much, much longer. That makes it even noisier, and even more likely to break or wear out.

RAY: So along with overhead cam engines came rubber timing belts. Even over longer lengths, rubber belts are quieter, lighter, and cheaper. Since they don't need constant lubrication like timing chains, they can be housed outside of the engine like the fan belt or alternator belt. That makes the engines simpler and easier to service.

TOM: And besides, changing a timing belt is not that great an expense, and it's usually done only once in a car's lifetime. Depending on the car, it costs between 150 and 300 dollars, and most manufacturers recommend changing it at 60,000 miles. So if you're lucky enough to still own your car at 120,000, you spend a couple of hundred bucks and do it again.

TOM: This is progress, Paul. You have to change with the times. When the apparel industry went from metal chains to leather belts to hold pants up, people moaned about durability too. But that turned out to be a pretty good move in the long run, didn't it?

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