My first question to Kyle; A couple possibilities were suggested. The power valve screw was over tightened when installed cracking the stem. The other (that several dispute) is that lake water getting into the engine is hitting the hot power valve making it brittle.
Kyle's response; Both theories are not true.
Concerning power valve to piston clearance Kyle replied; Piston to valve clearance should be 1mm +
We have taken the engine apart and found that the power valve that broke was a power valve from when the engine was new and was machined again to match the cylinder during a recent rebuild. Could fatigue have caused the PV to break? I am not sure. New power valves have been machined to match the cylinders all the measurements have been checked and rechecked everything looks good. The ski will be in the water running again next week. Hopefully no more PV issues. If there are further issues I will definitely send the engine back to DASA. As was suggested in this post.
Sorry I could not determine the exact cause for this power valve breaking. I truly appreciate everyone's input. The good news is, there was no damage caused by the broken power valve to the ring, piston, or cylinder.
Kyle's response; Both theories are not true.
Concerning power valve to piston clearance Kyle replied; Piston to valve clearance should be 1mm +
We have taken the engine apart and found that the power valve that broke was a power valve from when the engine was new and was machined again to match the cylinder during a recent rebuild. Could fatigue have caused the PV to break? I am not sure. New power valves have been machined to match the cylinders all the measurements have been checked and rechecked everything looks good. The ski will be in the water running again next week. Hopefully no more PV issues. If there are further issues I will definitely send the engine back to DASA. As was suggested in this post.
Sorry I could not determine the exact cause for this power valve breaking. I truly appreciate everyone's input. The good news is, there was no damage caused by the broken power valve to the ring, piston, or cylinder.
