Engine Case Selection -- page 3 of 3

Photos H, I and J show the engine we have finalized on for our first build. This is a Fichtel & Sachs 436cc (440) widely used in older snowmobiles. There are several features in this design that make it ideal for our purposes.

First of all the belt-drive fan and housing are easily removed, leaving a clean case flange for attaching a component plate later. The case is light, strong and compact with cooling fins to radiate internal heat. 

Finally, in photo J we see a metal retaining ring on both ends of the case. This makes it easy to drop in either a 2 or 4 bearing/shaft assembly; with retainers on both ends, axial shaft movement is controlled. If shaft "growing" binds the end bearings, a small space can be left between the bearings and securing rings, or wave-springs can be placed between bearings and rings to keep the bearings "loaded".

That wraps it up for this month's article. It will give you a few weeks to find and clean up a case and get ready for next month's Bearings section. Until then, keep plugging away and tell us about your ideas on the subject -- we'll post good suggestions on our web site.

Ken Rieli

Photo I

Photo J