Timing Components: Testing and Inspection

INSPECTION OF TIMING BELTS





The timing belts must be checked closely. Should the following defects be evident, replace the belt with a new one, Replace every 60,000 miles.
(1) Hardened back surface rubber, glossy non-elastic, and so hard that no mark is produced even when scratched by a fingernail.





(2) Cracked back surface rubber.
(3) Cracked or separated canvas.
(4) Cracked tooth bottom.
(5) Cracked side.





(6) Abnormal wear on side.

NOTE: Normal belt should have clear-cut sides as if cut by a sharp knife.





(7) Abnormal wear on teeth.
Initial stage:
Canvas on load side tooth flank worn (fluffy canvas fibers, rubber gone and color changed to white, and unclear canvas texture).
Final stage:
Canvas on load side tooth flank worn down and rubber exposed (tooth width reduced).
(8) Missing tooth.

TENSIONER PULLEY





Turn the pulleys to check for possible binding, excessive play, and unusual noise.