Guys, I need some opinions. I had a machine shop check my block and do the necessary work on it to get it ready for a rebuild after I tore the engine down. Keep in mind that I'm not building a hot engine, this is for more of a work vehicle/DD. Anyway, they tell me that the block needs a bore, so I say go ahead and they asked if they should purchase pistons. I said go ahead and had them balance the rotating assembly as well. I then pick up my finished bottom end and get it home. I'm pulling the pistons out getting ready to put the rings on them and find that all 8 of them have the oil ring groove machined through the piston casting. See picture attached. There are 2 roughly 2inch by 1/8th inch holes in each piston.

Is this OK? Would you put this in your engine? Should I go back to them and try to get them to replace the pistons and rebalance by rotating assembly?

 

Holy shinola! No, that's not gonna work

 

Those are the new pistons they sold you?!?!?!?!

 

is that the new balancing method?

 

what piston set is that ... tbh, the rings should never touch that spot, but if it was not made that way from the factory (after much R&D) it may cause the skirt to be weak or cause a hot spot ... but i have never seen one with a hole like that, but i have seen some with small round holes in the oil ring groove

 

As bad as that might look to you, it is standard on some stock type pistons.
It allows the oil to splash on to the oil rings to lube the cylinder walls.

 

Don,
That's the conclusion that I'm coming to. After looking at some other pistons on summit, they all seem to have a hole in this area. I guest the forged pistons I used before must have had some drilled holes for oil because I don't remember seeing something like this where I thought there must be a flaw with these pistons. When I first saw the pistons pictured above, I had the same reaction as everyone else. That's why I asked.