What is the ring gap on a 13 to 1 piston .004"?

 

1.5.000" should get it done, [img]i/expressions/face-icon-small-happy.gif[/img]

 

What Bore?
What brand piston?
NOS? Yes or No?
Is it a gapless ring set? lmao

 

Piston Ring Gap


This is a good guideline.

OMR

 

These sound a little tighter than I am used to. I don't like any more blow-by than absolutely necessary.......but on the other hand I have seen what DS motors do if the ring gap is insufficient. It isn't pretty and it was expensive[img]i/expressions/face-icon-small-wink.gif[/img]

The fall back advice I would give is to ask your piston manufacturer what they recommend for that piston and ring kit. They will ask if it is for a NOS application or not. On my 730 I ran a .022 ring gap. My 800 is setup for NOS so I have the ring gap at .028..........they are both 105.5mm bore[img]i/expressions/face-icon-small-wink.gif[/img]

The reason for asking your piston manufacturer is, #1 liability...........none of us want to tell you the wrong number and have it fail. Reason #2 is only your piston manufacturer will know the concentration of silicone in your forged piston. The effects the expansion percentage which will effect your ring gap also.

 

More Gap Specs


The effects the expansion percentage which will effect your ring gap also. !!!!!!!!!!!!!!

Rings float.

 

Thats true, rings float but in bore applications the cylinder is sized to the piston to maintain tolerances and piston expansion is part of what determines that tolerance. Optimal ring gap will change if the other variables change. IMHO

 

AHKN[img]i/expressions/face-icon-small-smile.gif[/img]