Timing Belt: Testing and Inspection

INSPECTION

TIMING BELT
1. Check the belt for oil or dust deposits. Replace, if necessary. Small deposits should be wiped away with a dry cloth or paper. Do not clean with solvent.
2. When the engine is overhauled or belt tension adjusted, check the belt carefully. If any of the following flaws are evident, replace the belt.

NOTE:
^ Do not bend, twist or turn the timing belt inside out.
^ Do not allow timing belt to come into contact with oil, water and steam.

3. Inspect the belt closely. If the following problems are evident, replace the belt with a new one.
A. Hardened back surface of rubber. Back surface is glossy, non-elastic and so hard that when the nail of your finger is pressed into it, no mark is produced.





B. Cracked back surface of rubber.





C. Side of belt is badly worn.

NOTE: A belt in good condition should have clear-cut sides as if it were cut with a sharp knife.





D. Teeth are badly worn out. Initial stage: Canvas on load side of the tooth flank worn (fluffy canvas fibers, rubber gone, color changed to white, and unclear canvas texture)Last stage: Canvas on the load side of the tooth flank worn down and rubber exposed (tooth width reduced).
E. Missing tooth.





SPROCKETS, TENSIONER, IDLER
1. Check the camshaft sprocket, crankshaft sprocket, tensioner pulley and idler pulley for abnormal wear, cracks, or damage. Replace as necessary.
2. Inspect the tensioner pulley and the idler pulley for easy and smooth rotation and check for play or noise. Replace as necessary.





3. Replace the pulley if there is a grease leak from its bearing.