krys88

Hey guys, What ring gap are you running on manley pistons with 800-900whp? According to manley instruction I should go .026 on top and second ring which look a little loose to me. What you guys set them to? I was thinking 18-19 on the top ring and 22-24 on second ring. Thanks!

schuhie

I'd run what they suggest. They did the engineering and testing.

krys88

I might go with what they recommend but seems little to loose for me. Are you using manley pistons?

schuhie

I'm personally running wiseco's and went with their called out gaps.

Tim M

We recently built a 4G63 with Mahle pistons for ~400 CHP. We elected to use .018 top. I'd definitely look to widen the gaps for 900 WHP...more HP, more heat...more expansion...

krys88

I think I will go with 22 top and 25 bottom. I will not go as wide as manley recommend 26 for this boost level. I build engine before with wiseco pistons and I made 19 top ring and it was making over 700whp for over 5 years, but manley recommendations are quite different to wiseco that's why I was not sure. Thanks!

Tim M

krys88: I find the ring gap an odd thing as well. I'd think most rings are similar materials with similar expansion characteristics. Other than ring land position, I would think pistons are a constant. HP number would certainly drive the gap, but seems like there would be more consistency.

And / or companies vary in their willingness for risk acceptance. Obviously, the perfect ring gap for your engine is one that goes to zero at the highest heat rating...can be done with trial and error! ;-)

krys88

Exactly!! I was reading somewhere that wiseco and manley use the same manufacturer to make piston rings but they clearances are totally different. Look like some companies don't want to take a risk and it is better to give customers instruction with wider gaps so margin for error is lower.