new piston rings

[Philip]

just a followup on my piston ring project. the gaps on my old rings were .070 compression and .150 on the oil rings.
the rings are not worn thin so i am not sure what went on there. i ordered some .010 over rings from chaffins. i slid one
in the bore and it tight with no gap as it should be so i will grind the gaps to about .012 and install them. i have two sets of pistons
the ones that were in the car and a second set. the second set have tighter ring side clearance and generally are in better condition.
they do not have the oil drain holes that my other pistons have on the oil ring groove. i have received advice to drill these holes
and advice to not drill them so i dont really know what i am going to do. the issue to begin with is oil getting past the rings. philip

[Adam]

If there is much more than .002” clearance in the ring groove, it’s possible the new rings may still pump oil. If you don’t have the engine out, then replacing the rings and seeing what happens is the most logical course of action. If you have the engine out; then boring, honing, and properly fitting new pistons and rings will be your best course if action.

[Scott_Conger]

If you got advice to use pistons that had been modified with holes, to "fix" a problem 70 years ago, it wasn't very good advice.

[GrandpaFord]

Phil, All modern pistons have the holes in the oil ring grooves.

[Scott_Conger]

And that is all well and good for modern pistons with oil rings.

Model T's do not have oil rings. Just 3 compression rings.

[Kerry]

That being true, the original piston only had 3 compression rings but over the years many styles of replacements.
4 different oil ring styles, 3 different pistons with oil relief holes.

[kelly mt]

I rebuilt a motor last year with iron pistons that had been drilled with six holes around the lower ring groove. In asking about this I was told that period racers did this. These were old standard size pistons. I wouldn't do that on a road car. I also found a set of pistons with the second groove drilled, again racers. PK

[Kerry]

The oil relief holes in the centre and right pistons in the photo are below the second ring, drilled in a shamfer that is machined just under.

[GrandpaFord]

If the 3rd, or 4th, ring does not have the slots, then there is no need to have the holes in the pistons. If it does have the slots, then the holes should be drilled. If you don't have the slots then you don't have an oil control ring and all the rings are compression rings. The rings should be close fitting in the grooves and the gaps should be correct. The huge gaps that Phil reported will allow lots of oil to be pumped above the pistons. If the rings do not fit tight in the grooves then they will pump oil into the combustion chamber.

For my money I would change out to modern aluminum pistons with an oil control ring, but it is Phil's car and he gets to do what he feels is best. Aluminum pistons also means more work and money.

[Mark Gregush]

I looked at 5 more CI pistons, 5 that came from same engine, oil holes, the 5th, oil holes. So that makes 9 CI with oil holes.