Box Stock

More Compression...

I like the flat top but keep that quench in check if you start milling. Those motors if setup loose get some piston rock you don’t want to start kissing the head with your piston. You can cut everything down as low as you want for compression but if the piston and head only have .010/.015 between em at TDC that could get sketchy. Then your back to adding a thick head gasket that’s possibly not legal in the class or starts to negate your quest for compression in the first place.
 
I'm hoping this is not a stock class with set rules? RWYB? or Open, stock appearing? If its an AKRA or NKA sanctioned class then you are limited to 26.5cc and stock piston.

As long as its open, your best bet is a flat top piston and deck the block for perfect "0" then mill the head and keep an eye on quench, leave some room if turning high RPM as these aluminum rods stretch... They also make smaller chamber heads for clones.
 
Its on our racing mowers. If I cut some off the head I'm thinking to save a couple bucks on a couple engines I have. Our rules are reasonably open (to a point). Flattop or milling is ok.
 
These engines like compression, do both also advance the ignition, be aware of valve piston contact and the spark plug.
 
You must log in or register to reply here.
Back
Top