54Chevy, to answer your curiosity, on our race motor we use sleeves as a surrogate bore surface to cut down on friction in the engine. Ours are a special thin wall sleeve that is made in the U.K. and comes with less than 1mm wall thickness. Our engine is a GMC 302, 60 over.

After hot honing our blocks to replicate running temperatures we found that it is still had distortion in the cylinders and also we were not able to put the desired profile we wanted to have. With the sleeves we were able to put the proper taper and profile before installing them. Even though hot honing takes most of the distortion out, we were able to further reduce friction by manipulating the process by hand to put the required taper and profile in the liners. These are dry installed and we used a Nickel-Ceramic plating giving it a ‘oleophilic’ finish with low friction (Ra 0.15-0.30). With this coating we also had to use a Titanium Nitrade coatings on the rings.

In the reciprocating piston environment where relative velocity changes greatly, it is not possible to modify pressure greatly without effecting performance. But by manipulating and modifying the surface roughness we can alter the effectiveness of the lubrication to cut down on drag. Being in Silicon Valley I had some of my engineering friends use computational fluid dynamics to develop a computer program that predicted how the oil film will behave and we were able to validated this by using ultrasonic transducer technology. We have found that this did reduce ring friction. How ever if it is not applied properly it can be detrimental to the engine.

It is not straight forward as it sounds and it is extremely expensive and a lot of work, but in our case we are looking for every last horsepower we can get.