The chain drive system has enough slack in it to cause cam timing to vary several degrees. Unstable timing of valvetrain could account for some of the noises. If the tensioner shoes get worn out, by the time you hear noises, severe damage will be done to the engine. Get a manual and examine them soon. You have to decide between frequent checks, changing over to the new styly roller chain & hyd. tensioners, or Gear drive for longevity. |