erich
10-22-2004, 03:39 PM
I get asked a lot, "what is the difference between the cast iron and aluminum cylinder kits?" Well here's why:
The Airsal aluminum cylinder is cast from an aircraft quailty T-6 aluminum, then the cylinder is coated with a Nikasil lining. The Nikasil coating used in our cylinders is a nickel and silicon carbide matrix coating about 0.07mm (.0025-.003") thick. The nickel matrix is very hard, but it is comparatively ductile, whereas chrome is brittle. Dispersed through the nickel are particles of silicon carbide less than 4 microns in size. These extremely hard particles make up 4% of the coating and form a multitude of adhesion spots on which oil can collect. Beside providing a very long wearing surface for the piston and rings, the silicon carbide particles also contribute to longer engine life by ensuring good cylinder lubrication.
This superior process was developed by the German firm Mahle, originally for use in the Mercedes Wankel rotary. Porsche uses Nikasil in their turbocharged 917 - 935 series of race cars. In racing two strokes both Morbidelli and Rotax have had great success with Nikasil and of course it is used in thousands of professional grade chainsaws. The major drawback to chrome plating is the fact that chrome can flake. It is also easily damaged by dirt inducted into the motor.
The worst thing that can happen is you will have to replace the piston when excessive miles are on it. Just because the cast is aluminum, it isn't going to distort or wear like other aluminum parts, due to the Nikasil lining. Cast cylinders also do not have the silicon carbide that aids in lubrication of the cylinder wall. Still people will choose the cast iron boat anchor over the lighter and batter cooling/lubricating properties of the aluminum, and that's fine, we'll continue to carry them. And really, the cast iron works fine, and has for many years, its just that given the advanced technology that has gone into the aluminum T-6 cylinder, and what it means to the scooter enthusiast, it will continue to be my choice of cylinder.
The Airsal aluminum cylinder is cast from an aircraft quailty T-6 aluminum, then the cylinder is coated with a Nikasil lining. The Nikasil coating used in our cylinders is a nickel and silicon carbide matrix coating about 0.07mm (.0025-.003") thick. The nickel matrix is very hard, but it is comparatively ductile, whereas chrome is brittle. Dispersed through the nickel are particles of silicon carbide less than 4 microns in size. These extremely hard particles make up 4% of the coating and form a multitude of adhesion spots on which oil can collect. Beside providing a very long wearing surface for the piston and rings, the silicon carbide particles also contribute to longer engine life by ensuring good cylinder lubrication.
This superior process was developed by the German firm Mahle, originally for use in the Mercedes Wankel rotary. Porsche uses Nikasil in their turbocharged 917 - 935 series of race cars. In racing two strokes both Morbidelli and Rotax have had great success with Nikasil and of course it is used in thousands of professional grade chainsaws. The major drawback to chrome plating is the fact that chrome can flake. It is also easily damaged by dirt inducted into the motor.
The worst thing that can happen is you will have to replace the piston when excessive miles are on it. Just because the cast is aluminum, it isn't going to distort or wear like other aluminum parts, due to the Nikasil lining. Cast cylinders also do not have the silicon carbide that aids in lubrication of the cylinder wall. Still people will choose the cast iron boat anchor over the lighter and batter cooling/lubricating properties of the aluminum, and that's fine, we'll continue to carry them. And really, the cast iron works fine, and has for many years, its just that given the advanced technology that has gone into the aluminum T-6 cylinder, and what it means to the scooter enthusiast, it will continue to be my choice of cylinder.