Originally Posted by balloonman
At 34,666 something went klunk bent the intake valves. Now I need a cheep complete used head.
The doo spring was broken and balance chain jumped a tooth. Not sure how many teeth the cam chain jumped. Exhaust left cam cap broke at the grove and was ground well. Captain Tom
I've seen people crack the left side cam caps by not getting them properly lined up with the ring on the camshaft that goes in that grove. I know because I did that and had to do a JB Weld repair. I suspect your doo spring gave out and some how got trapped in a way that caused the cam chain to jump when the balancer chain jumped, as the sprockets for both chains are side-by-side on the crankshaft. When the cam chain jumped this more than likely caused the intake valves to be opened when the piston came up.
Question would be how often did you do the balancer chain tension adjustment? If this adjustment is not done frequently the doohickey can be in the position that leaves the spring stretched, leading to premature failure.