The two 3 1/4" bore piston ring styles for the B & P series Onan Twin Aluminum Block engines can be determined by using change from your pocket if you don't have a mic or caliper handy.
BG B43 B48 P216 P218 P220 etc.
Note:
Various Casting Numbers were used over the years on these pistons. Appearance will also vary.
But, ONLY two ring styles will be found. Enter part numbers below in our site search for detailed specifications. Ring thickness in Fractions, Decimal & Metric will be found. Clicking on any thumbnail picture in search results will open the full product info page.