Cylinder bore geometry is an often overlooked part of building small racing engines. Roundness, taper, surface finish, and cross hatch angle are all important factors that must be addressed. To produce optimal horsepower, a cylinder must be perfectly round and straight, anything less and your rings are not sealing properly. Here at JRPW, we diamond finish our cylinders on a Sunnen automatic honing machine. This machine produces a perfect cylinder every time, with a consistent cross hatch angle. Size, roundness, and taper are verified to .0001 and finish is checked with a Mitutoyo profilometer. Factory cylinder finishes as well as those produced by portable hone heads will not yield the accuracy we require at JRPW.
Just a few points to consider when choosing your engine builder or machine shop. Technology and accuracy produce results.