NKA Clone Rules

40.4.14 Bottom ring is a non-tech item regarding tension. Bottom expander ring & two rail rings, when mounted on piston and rod in place should support piston in cylinder when inserted upside-down
what exactly does this actually mean? what happens if the piston and rod fall out the bottom? why is there a check on a non tech item?

40.4.12.6 No flat top piston allowed, must be dished-OEM w/no modifications.
40.4.12.7 Aftermarket pistons and/or sizes up to .25mm (.010") over are permitted.

which one is it?????
 

OVALTECH1

Site Supporter
I build to .010 over is the max bore diameter.. so I use the biggest piston available if need be which is the .0075 piston with .002 piston to bore.
 

OVALTECH1

Site Supporter
As far as bottom ring pack it’s kinda like the wrist pin deal.. there is no set tension rule but they have to be able to hold their own weight in their accompanying bore.
 
As far as bottom ring pack it’s kinda like the wrist pin deal.. there is no set tension rule but they have to be able to hold their own weight in their accompanying bore.
what wrist pin rule?
I build to .010 over is the max bore diameter.. so I use the biggest piston available if need be which is the .0075 piston with .002 piston to bore.
one stated must be OEM, next states aftermarket permitted.
 
As far as bottom ring pack it’s kinda like the wrist pin deal.. there is no set tension rule but they have to be able to hold their own weight in their accompanying bore.
Stated in rules, piston "when mounted on piston and rod in place should support piston in cylinder when inserted upside-down. Does not state that it must support piston in bore. Oh yea, what about piston arrow?? i know someone that got pitched over piston installed with arrow in wrong direction, where is that stated in the rules?
 
I build to .010 over is the max bore diameter.. so I use the biggest piston available if need be which is the .0075 piston with .002 piston to bore.
Actually, a .25mm (.010") piston is available, and it is legal. There is no maximum bore size stated in the rules. in fact there is almost nothing in the rules about the block other than the line about welding for rod damage, and piston pop up. But i have seen tech man measure the bore and not the piston to determine legality, when no maximum piston to bore clearance given in the rules, the bore should never be measured in tech.
 
There is no maximum bore size stated in the rules ...But i have seen tech man measure the bore and not the piston to determine legality, when no maximum piston to bore clearance given in the rules, the bore should never be measured in tech. ....
Actually, a .25mm (.010") piston is available, and it is legal. There is no maximum bore size stated in the rules. in fact there is almost nothing in the rules about the block other than the line about welding for rod damage, and piston pop up. But i have seen tech man measure the bore and not the piston to determine legality, when no maximum piston to bore clearance given in the rules, the bore should never be measured in tech.
40.4.12.4: Standard bore is 2.685”, maximum overbore allowed is 2.700”.
 

OVALTECH1

Site Supporter
As far as the piston it’s the dished oem style piston that it came with. You can use an aftermarket replacement just not that flat top Honda or 212 style piston. Arrow points towards the pushrods.
 
40.4.35: Wrist Pin Dimensions 40.4.35.1: Wrist pin inside diameter: .555” maximum

40.4.35.2: Wrist pin outside diameter: .707” +/-.005”

40.4.35.3: Wrist pin length: 2.100”-2.200”
It was implied by OVALTECH1 in a post above, that the pin must support itself in its bore, where is that rule? And I still have not found the mysterious piston arrow rule anywhere.
 

K12

Member
It's not the pin that must support itself, it's the upper and middle ring. The oil ring must support the piston and rod less the rod cap and bolts.
 

flattop1

Dawg 89
I see nothing about the pin holding itself or the arrow .
Compare to known stock is there .
It also states axle stiffener allowed .
Next rule no stiffener allowed .
Need a addendum .
 
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