http://www.duramaxdiesels.com/forum/showthread.php?t=27638
The first LBZ pumps had some issues, as is stated in this thread concerning the ceramic check balls. The best option that Bosch chose for the system was to use a check ball to close the high pressure port, after the fuel was pressurized. Then the ball would seal the port and the plunger would pressurize another shot of fuel and the process repeated. Some also were heat treated above RC60, and suffered internal and external cracks. The LBZ/LMM and Cummins 6.7 CP3 all share the same design, with very little difference between the two. The pumps that came on 2009 year model and newer are a little different that the earlier version. The tappets (buckets) are now softer (less brittle), the cascade valve is redesigned with raised internal pressure. Check balls are still ceramic, so they need to be changed out for steel ones.
It doesn't matter who built the pump, stock or modified, if the ball does not reseat for any reason, fuel that has already been pressurized will re-enter the plunger bore. It cannot be raised to a higher lever so the plunger breaks, and sends the parts out the side of the pump.
I have certainly had a few pumps fail over the years, unfortunately once they fail little evidence remains. I wish we knew all things that can attribute to these failures, all we can do is speculate.
For a very long time I refused to do the LBZ/LMM style pumps and used the LB7/LLY version in place of them with better results. After those became remans, I had no choice but to go back to the LBZ/LMM for the sake of quality. It has now come to the point where, we can no longer get anything new, even if they say new on the box, if they are painted black they are a reman. They also seldom flow what what a brand new one does.
I pioneered the stroker CP3 which has been the subject of duplication for years. It doesn't matter who the company is, who offers increased displacement pumps, they will all suffer failures. I guess if you just fell off the turnip truck with no history, you can start with a clean record to make folks think different. Its not the builder its the design, and we can't do much about it except do our best to make it right in the customers eyes.
A modified regulator is worth over 20lph @3500 rpm on a 10mm stroked CP3, wonder why the expensive pump comes with a stock one?