Engine failure question

[Moparteacher]

The piston-to-head contact can be a result of the failed bearing.

A misfire or abnormal combustion puts an extraordinary load on the bearing. A misfire can load up the cylinder with fuel resulting in a hydraulic cylinder and that crushes the bearing causing the bearing shell to lose it's crush and allowing the bearing to spin.

Detonation and/or preignition will crush a bearing also, resulting in a spun bearing and piston-to-head contact.

Piston-to-head contact is usually a result of a spun bearing and not the other way around, unless of course the builder is incompetent and fails to check clearance.

As already posted, resolve of the missfire is priority to making a run. If the run was made with knowledge of the missfire then the engine builder has no liability and the owner bears all.

Gary Weaver
College of Southern Nevada