Don Terrill’s Speed-Talk

13 deg. 15-1, race gas, drag race, total seal ap top rings, Napier second. Std. Tension oil ring, vac pump.

.018 - .021

Or more.

Piston material?
Block filler?
Target run temp?
More info.

I would set them at .024 and .030 2nd.

2618 forged. Probably 175 degrees race temp. No block fill. Darr lil m block.

.0045" to .0055" per inch of cylinder bore for the top ring; .0060" to .0070" for the second ring.

I would go with mark's recommendations for the top ring and open up the second ring to .025

Why are you running a standard tension expander with a vacuum pump?

rewguy wrote: ↑Thu Oct 11, 2018 11:05 pm 13 deg. 15-1, race gas, drag race, total seal ap top rings, Napier second. Std. Tension oil ring, vac pump.

Are the pistons gas ported in any way ???
And why a std. oil ring with a vac. pump?? Why no go with a low tension oil ring?? Issues with the combo before??

no reason. I just put back exactly what was in there.

Top .027"

Second .030"

rewguy wrote: ↑Fri Oct 12, 2018 10:01 pm no reason. I just put back exactly what was in there.

Then run it the way you did.
Why people set them at the closest they will ring butt is beyond me!

I'm with ya Adam, there isn't enough TIME, at any kind of reasonable racing rpm,for a couple thou extra to make a difference, gap within reason and put extra safety to it if you are worried about having to chase your tune.

Then put a vacuum pump on it and fuggit 'bout it.