tjkj2002 wrote:
Your confusing timing chains and timing belts.
Timing belts have a change interval between 40k-100k depending on model and timing chains generally outlast the rest of the engine.
Not necessarily. The 2.7 has a chain and they love to break, especially if you do a lot of high RPM acceleration. Undone, the chain is about 4’ long. They stretch until the tensioner cannot keep them tight any more. Once they are loose, the slack allows the cams to jerk the chain as they turn. Then it's only a short time before they break. I've repaired dozens of them. It bends all the intake valves. I’ve has some as low as 80K and as high as 140K before they break; it all depends on how hard you drive. I didn’t know if 3.7 shared the same fate, I wanted to do some preventative maintenance.