4D55 Ranger Diesel Ring Breakage

[Toby]

Does anybody here have any idea why the Mitsubishi 4D55 motors in Ranger TDs break rings? Every one that I have had apart has had broken rings. Usually all of the top compression rings. My 99K original mile rig lost all compression in one hole. It had broken all the compression rings on a 175 mile trip to Portland, with zero abuse and no speeds over 75.