MiataMir

Got my rings back from the machine shop and want confirmation on if they are good to go.

I had asked for .018" on top and .020" for the second ring. Upon measuring myself, I see that the tops are around .021-22" and the second rings are around .023-25" (The second rings came out of the box with those values, no filing was done)

Piston to wall clearance was also set to .0035 for wiseco pistons as well.

I am aiming for around 350hp with an efr6758, are these ring gap numbers too loose or am I good to send it?

If so, any chance blowby will occur at these gap levels?

der_vierte

You are good to go, send it.

Not going to be a problem with blow by.. but at these power levels a good CCV system is always a good idea

LeoNA

I would double check the PTW, if it is .0035” I would increase it. The ring end gap is fine. Increasing the the PTW by .001” will increase the end gap by .003”. End gap will still be ok.

MiataMir

I appreciate all your help guys!

For wiseco pistons, I thought .0035" was the number many people shoot for. Many people on forums have run that number or have recommended it. I could be wrong but I believe that was the number I got after reading the sheet that came with my pistons and after reading a bunch of posts regarding piston to wall clearance. Any reason to go more than that?

LeoNA

From experience it proves to be too little for this application. Forced induction, high expansion piston material, low expansion block material and the target power level.

MiataMir

Ok I see. I think Ill keep the piston to wall clearance as is just because I had just corrected from .0025" from another machine shop to .0035". I was more concerned about ring gap since I did not see many people with numbers like mine regarding ring gap. Do you have your ring gap numbers by any chance?

curly

iTrader: (25)

Mine has been running well at 300hp for some time now, similar ring and piston to ring tolerances. I believe I requested .018 and .020, and a few of the bottom rings were larger, up to .024 IIRC. I've had very little oiling issues, outside of my EFR, but that's another story. Radium catch can gets nothing in it, and the exhaust side is actually open to atmosphere, and has always been bone dry.

MiataMir

Thanks for the info Curly. LeoNA may have a point on it being small as Ive seen people run larger clearances, but I am comfortable with the following PTW clearance I have currently. I think Ill send it with the gaps I have