3. 1.Failure occurs at the intersection of the round pocket and the outlet rifle drilling (just barely visible in white, behind the yellow outlet plunger), which goes out of the head at the brown fitting seen on slide 1 2.Failure occurs at this little chamfer, where the narrow drilling opens up into the pocket for the inlet check valve plunger 2 1

4. Part fails in fatigue out of arrowed area, which is #2 from the previous slide. The picture on the left is broken on a plane going in/out of the cartoon on the right (the red line is supposed to represent that) Two crack fronts – one starts out of the intersection of the drilling with the pocket, and then eventually the stress state becomes unstable enough that a second overload crack develops where the yellow plunger strikes the seat Drilling Stable, fatigue crack Overload crack, final stage

5. Residual Stress Data Current production flow: Stanadyne CT machines, Nitrex Aurora IL nitrides Gives a good part, very good residual stress Proposed production flow, needed to maintain production in 2011: Stanadyne China (SCC) machines and nitrides in-house Weak residual stress, parts can’t pass source approval testing