I took apart one of my hydraulic roller lifters. When I went to reassemble it, I noticed that the lifter body has holes on the outside on the fore and aft side of the lifter. The small piston that goes inside also has small holes in it. Do the holes on the lifter body and on the piston need to be aligned when reassembled? The piston is completely round, which tells me that it is free to rotate inside the lifter body if it needs to. So, that tells me that even if the holes were installed lined up, they could go out of alignment when the engine runs. Thanks.

 

They don't need to be aligned up. Make sure you get that small spring that's in the bottom of the lifter assembly strait up and down. I took mine apart and one of those springs was laying in there sideways and the lifter wouldn't pump up and it caused my rocker to slap the top of the valve stem because I couldn't get it adjusted. Ended up taking the top end of the motor apart. Just trying to save you some headache.