* Too Much Valve Lash
* Damage To Valve Springs, Locks, Push Tube Or Worn Valve Lifter
* Not Enough Lubrication
* Damage To Valves
* Damage To Camshaft
1. Too much valve lash:
Check and make necessary adjustments as per Testing and Adjusting Section of the Service Manual.
2. Damage to valve springs, locks, push tube, or broken or worn valve lifter:
Install new parts where necessary. Broken locks can cause the valve to get into the cylinder. This will cause much damage.
3. Not enough lubrication:
Check lubrication in valve compartment. There must be a strong flow of oil at engine high rpm, but only a small flow of oil at low rpm. Oil passages must be clean, especially those that send oil to the cylinder head.
4. Damage to valves:
Make a replacement of the valves and make an adjustment as necessary.
5. Damage to camshaft:
Make a replacement of parts with damage. Clean engine thoroughly.