I got my block back from the machine shop and am ready to set the piston ring gap.

Can someone tell me what the ring gap should be for the Keith Black 237 piston? The KB sight is not working. I bought the matching KB rings.

Thanks,

KB hypers I'm assuming? What app (street race nitrous etc)& I'll look it (top ring gap) up on their white sheet

Thanks Robert,

They are the Hyper going in a street 440.

Thanks

top ring gap .0065" per inch of bore. 2nd comp ring same as normal which for me is .003" per inch of bore. I do not go with the fad that the 2nd comp ring needs to have a way larger gap to let gasses escape. the top ring having a gap of (.004") per inch of bore and 2nd ring (.003") per inch of gap has worked well for decades with the only change needed with the KB hypers is the top ring needing even more because of the KB's design.

So on my .030 motor a top ring gap of .028 and bottom gap of .013. Sounds like a tight bottom gap.
This is my first go at this so I appreciate your time and effort.

Thanks,

You can go .018 on the second ring or delete it all together. Of course, you are talking a street ride.

I have one 451 out there in a 64 Savoy four door and it runs on the street without the second ring. Now I know I'm going to get killed about this, but before you react, John Erb, long time cheif engineer for KB told me to try it and check the HP production of one of my other engines using the full stack. HMMMMMM a full eight HP and no smoking or oil usage. Since the distance between the bottom and top ring on the Hypereutectic pistons is so long, there is no trouble with rocking. That and the tighter bore they require.... Just a thought. I sure wouldn't use a .013 ring gap for the second ring.

Peace, Rev. Mopar

That is pretty amazing to me classof65. I never heard of leaving out the second ring.

So does .028 top gap and .018 second gap sound good on the hyper?

Thanks,

I've used the .0065" top ring factor and .003" on the 2nd ring on KB's w no issues

The larger second gap nowadays is not a fad. There are people with a lot more knowledge of the subject (and oem manufacturers also). Engine masters also. It's trickled down from the high eng race teams. It's to aid in controlling/preventing top ring flutter/unseating from pressure built up between the top and second ring.

30 year ago, the thinking on ring thickness was different. Now we know we can run much thinner in oem and full on race engines. There are factory "low tension" oil ring expanders too.

To each their own though.