Whizzer "h" Model Piston Ring Installation Question

Discussion in 'Whizzer Motorized Bicycles' started by doc-detroit, May 29, 2010.

  1. doc-detroit

    doc-detroit New Member

    The top (2) compression rings for my Whizzer motor have a bevel on the inner edge and no "pips" or other markings. I've read conflicting information on the proper orientation of these rings on the piston. What is the proper orientation for a "H" motor?
    The piston is marked WMJ 2182 which is a Whizzer, lt. wt. .005 OS part, but the rings may be after market. I have no idea.
    Good day!

  2. doc-detroit

    doc-detroit New Member

    For those following this post, Quenton was kind enough to provide the answer. The bevelled edge on the inner edge of the compression rings face up towards the top of the piston.
    Thank you!!


    Very true

    From what I know, with most engines, if not all, the piston compression rings should always have some kind of bevel or ridge on one inside edge of the ring. This is to allow positive sealing when the combustion cycle occours. When the pressure builds up on the compression stroke, gasses start to "blow-by" the compression rings and work in around the ring lands of the piston, pushing down and outward against the piston ring at that beveled area. If the rings were installed with the beveled side down, the pressure would push the rings inward, increasing the "blow-by." Notice that some rings are clocked across from one another or every 120 degrees. This is so the compression gasses have to work around the piston to reach the ring gaps. Ive noticed the pins in my piston on my 66cc engine. This is so the ring does'nt rotate and the gaps dont snag the ports in the cylinder.
    Last edited: Jun 10, 2010