blu00rdstr

Could someone tell me ring gap for Diamond forged pistons in a blower install?

I've heard .035 on both, I've read .015-.020, and 2nd ring gap is 1.5x top ring.

Does blower make a diff? Forged pistons?

LOnSLO

iTrader: (15)

.035" sounds way high. You will be fine with the .015 to .020 gap.

Vents

iTrader: (9)

i think with a blown application i'd defiantely call diamond. Chris is absolutely excellent to deal with and im sure he could tell you anything you'd want to know.

AP-Engineering

How much boost are you planning on running? If you are around 10-12 pounds you can get away with .018 on the top ring and .020 on the 2nd ring. If you are running more than that for boost then I would go up ion gap accordingly. Running .035 for gap would be a lot. You would have a lot of blow bye with that much gap!!

Chris Gelineau
Diamond Pistons
877-552-2112 toll free

theblur98ss

iTrader: (71)

On my diamond pistons the gap was .050. My builder called diamond and they said as long as it was under .060 it wasn't a problem.

AP-Engineering

The under .060" was on the oil rails, not the compression rings. If you ran that much gap you will end up having a lotof blow bye.

blu00rdstr

Thanks Chris! That's exactly what I'm looking for, I am aiming for 12psi or whatever I can get away with using 91 octane. I installed the oil rings. No need to check those, right?

I test fit the 2nd and 1st rings in the cylinder and the ends overlap. Is that normal? The bores were opened up with a hone to get the proper clearance for the pistons, but the bores are still too small for the rings.

I searched the bay area for a piston ring gap grinder, no luck. So I'll gently scribe and file ring ends tonight.

phenyxTA

You can use a dremel tool with a sander attachment, they work awsome. Just do a little at a time.

Cann

Chris, what ring package would you recommend for a big bore 20 pounds of boost application? TIA

blu00rdstr

Um, slightly overfiled a top ring. Maybe two. Most of the top rings are .018, and the second rings are exactly .020. But one or two of the top rings got to .022, I measured (feeler gauge didn't fit), filed, and measured (feeler gauge can tilt in slot), cursed.

Am I OK, or should I ask Diamond to FedEx two top rings?