Timing Belts • All timing belts need periodic replacement

• Critical for “Interference” engines Some engines are free running or non‐interference

Other engines will have strike the valve if timing breaks or is improperly installed

• Timing Belts should be replaced at recommended mileage

• 60,000 – 90,000 miles are common

• Timing belt should be replaced with any signs of wear

Badly worn – should be replaced even if cracking is very minor Teeth can strip and not turn even if belt does not break Check for Coolant and Oil Leaks

• Any coolant or oil on the timing belt will deteriorate the belt and cause early belt failure.

• If timing belt drives the water pump it is best practice to replace both at the same time Replace Idlers and Tensioners on High Mileage engines

Timing belt kits are available with all new rotating parts (Tensioners and idler pulleys) Check replacement Belt against old one. Not ALL belt teeth are the same style Check replacement Belt against old one.

• Count the number of teeth to make sure both belts are the same.

• Mark OLD belt BEFORE removing.

• Mark on EACH pulley

Count teeth when transferring marks from old belt to new belt Read ALL procedures

• Always rotate belt by hand at least 2 revolutions to ensure timing is accurate and to set tensioners.

• Tensioner pre‐load is critical

• NEVER turn in opposite direction –may ruin the tensioner, may cause belt to jump a tooth when engine starts Rotate at

• Remove spark plugs

• This allows engine to turn over easier

• (Mark wires as will cause misfire –rough running if plug wires on wrong plugs)

• Rotating from Camshaft will over – torque sprocket and may cause this bolt to break! Turn This Crankshaft Counter‐Clock Wise Tensioners take up slack. Turn so pulls on camshaft –NOT the tensioner

Turn This Crankshaft Clock Wise Turn This Crankshaft Counter‐Clock Wise Turn This Crankshaft Clock Wise Turn This Crankshaft Clock Wise Read ALL procedures

• Tensioner adjustment is critical and not all adjust the same way

• Some dual camshaft engines use a special holder to prevent the valve springs from turning the camshaft as timing belt is removed Double Check Camshaft timing

• If you get off by only one tooth the engine will run smoothly but have VERY low power

• If you are off by more than just a few teeth the engine will not run

• If you are off on cam timing cranking the engine with the motor can bend valves! Double Check Camshaft timing

• If you are rotating the engine by hand and the crankshaft gets very difficult to turn…….

• ….STOP! –this may be a valve that is contacting the piston

• https://youtu.be/V2ipLYeNad8