two piece D4 pistons and etching?

Best bet on the two piece pistons is to get rid of them. They were a mistake which Cat eventually corrected. The etching process is obsolete and was replaced by the ball type abrasive hones.

I had one of the two piece pistons come apart on my D47U and it wasn't pretty. The top of the piston came out the exhaust in a million pieces while it bent a connecting rod, trashed valve components, rod guides etc. When we dropped the oil pan it looked like Humpty Dumpty. Several thousand dollars later, and a lot of hard work we had it all fixed. I would not want to repeat this experience.

Doug, I know what your saying as I,ve seen it happen over the years back with them when they come in the dealer to repair.

Thank you fellows I will be changing the pistons. Concerning senior members mention of knurling. As I recall and please correct if I am wrong, that involved punch marking a worn piston to expand it slightly to make a better fit and also to relieve any stresses.

That may be the "poor mans" emergency version but the correct method is applied while chucked in a lathe and a knurling tool (roller) applies the cross hatch knurling pattern. Rarely done to pistons anymore........another lost art.

Groove inserts is apparently another lostg art. Does anyone put top ring groove inserts in anymore? Is there any place to get the inserts? I believe Perfect Circle made them, maybe other manufacturers.😕 They were an inexpensive way to fix up a piston as good as new, some say better, if it is otherwise not severely worn.