First had rear tranny mount break and motor started dancing around. Replaced that. Then had vibration and found #7 plug fouled (dry). Replaced the plug and still had small vibration. After eliminating other causes, pulled engine. Valve spring on #7 failed and dicked up the guide allowing oil into the cylinder. Didn't get to talk to the shop very long to see if the bent rod was #7. Is my logic correct that enough oil could have got into the cylinder to hydraulic it ?? Or could one of the reconditioned rods have failed ?? This is in my 406 which is a low rpm, big torque engine. It had 12,000 miles since built. We are currently rebuilding it again. Part should be covered by warranty.

 

i'd guess part failure before i would hydroliced. that'd be a lot of oil, and even if the hole wasn't gettign any fire it'd still blow some, most, or all of the oil, air, and fuel out each time the valve opened and the piston came up.