A Cummins diesel engine was pumped with 100psi of air pressure. Rather than the head failing, another part of the engine was revealed as the weak point under the high pressure. The document provides a brief observation about testing a Cummins diesel engine by pressurizing it and notes an unexpected failure occurred other than the head.

1. This is what happens when you pump 100psi into a Cummins Diesel, notice it's not the head that was the weak point !