[Alan Roehrich]

A gapless top ring is okay, although I rarely use them. I refuse to touch anything with a gapless second.

A top ring will cause oiling, if it leaks bad enough to create pressure in the crankcase and cause extreme windage.

If the bores are truly round, and have the proper finish, you can run the Total Seal Advantage package with a steel top ring, a cast Napier second, the spacers in the ring grooves (on top of the rings, not on the bottom) and as little as 8 pounds of oil ring tension. The bores have to be near perfect, you have to use the right assembly oil, and you need to break it in on the dyno.

I use Speed Pro SS-50U oil rings, and make my own oil ring package (Keith Jones at Total Seal taught me). However, for customers, especially if I do not know their machinist, I use around 12 pounds of tension.