A customer, at Ringwood-based Performance Unlimited, had their car towed in the other day because the engine wouldn’t run. The damage to internal parts of the engine were extensive and, unfortunately for the customer, avoidable. The car’s timing belt broke causing a chain reaction of internal-engine damage. Denny Norton, the owner of Performance Unlimited, feels bad for the customer. More than that, he began warning friends and other customers about the importance of replacing their timing belts before they break. “Generally, you should replace the timing belt after 100,000 miles,” said Norton. “It is expensive. However, if it breaks, there’s a good chance it will do damage inside your engine. It’s not uncommon to have a bill that runs as high as several thousand dollars.” Timing belts are made of a composite material. That the material can last as long as 100,000 miles speaks highly of it’s durability (with some cars, it’s recommended that you replace the belt after 60,000 mil...