Geoffrey

My pistons are complete and I should have the cylinders mid week next week. The pistons are not as nice as what 9M offers, but due to my timeline and nonstandard configuration meant that 9M were not an option for me. I'm satisfied with these and I think they'll work for what I need and represents some new technology that I'll incorporate into a better piston with the next engine. They are an unspecified bore with an unspecified compression ratio and made from an unspecified alloy, but will still allow me to run 93 octane street fuel. The piston skirts have been coated with a graphite coating to aid in wear reduction and dampening when thrusting against the cylinder at TDC. There has been a significant reduction of weight over the standard Mahle 3.8 RSR pistons.

The ring package is extremely expensive and very nice, costing 3x what a standard ring package would. It consists of a very thin .7mm coated top ring, a .7mm second ring, and a 2mm low tension oil control ring. This compares to 1.5mm, 1.75mm, 3mm on a stock RSR piston. These new rings should seal better than the factory rings and will better conform to the changing bore size of an air cooled engine as it heat soaks. The thinner rings will seal better at the higher RPM range than the factory cylinders and will keep them from fluttering and losing seal.

I'll post pictures of the cylinders when they come.

New piston with the top and second rings on the left, and stock piston on the right.

garrett376

That stock piston looks gigantic compared to your new one!

Geoffrey

Thanks, I'm doing my part to downsize...

new piston diameter is larger than RSR though...

BlueHeeler

Piston ****.

Larry Herman

Looking more and more like motorcycle technology. 9,000 rpm is positively mundane for them.