Re: First engine rebuild fail...
If cam timing were the problem, there would be 8 valves making the same contact - they are all equal.
Intake valve contact would only happen at or approaching TDC on the compression stroke and the valve should be closed well ahead of that. Cam couldn't have been off enough degrees or it wouldn't have started easily as the intakes would have been open on the compression stroke, might even have been back firing through the intake.
A pushrod that bent would be because it tried to open a valve that was stuck, not because the valve was pushed closed by piston contact.
My guess would be that the valve hung up in the valve guide, which was (and still would be) too tight, or was not lubricated well enough. When you were running it at higher RPM it was moving freely but building heat and then when you dropped the RPM the valve stuck in the guide, contacted the piston, bent and was now really stuck in the guide and then the pushrod bent when it tried to open the stuck valve.
I would pull all of my valves and check the guides for size and look for signs of tight guides. Stick a good valve in the guide of the bent valve and see if it is free moving.
__________________
Four time Baja 1000 winner, four time Baja 500 winner. Solo'ed the Baja 1000 to LaPaz/Cabo twice.
4-Wheeling since 1972, Desert Racing since 1989.
AgileOffRoad.com
|