Standard-Bore Piston Ring Set for One Cylinder – Onan 3.25-Inch Twins (Early-Style Piston) This is one standard-bore piston ring set, enough to rering a single cylinder. Because the Onan B-series and P-series are two-cylinder engines, a complete engine needs two sets – order two. The rings replace Onan part number 113-0314, which supersedes the earlier 113-0189 and 113-0186. Bore size is 3.25 inches (82.55 mm), standard. Fitment Fits Onan B-series and P/Performer-series engines with a 3.25-inch bore built prior to Spec D: B43E, B43G, B43M, B48G, B48M, BG, and BGE (specs E through H), and P216G, P216V, P218G, P218V, P220G, and P220V. Early-Style Piston – Confirm Before Ordering These rings fit the early-style piston, identified by casting number 112-0163 or 112-0246 and by .078-inch (2.0 mm) top and second ring grooves with a three-piece .186-inch (4.75 mm) oil ring. As a field check, a US nickel is roughly 2 mm thick and will sit in the top two grooves of an early piston. Late-style pistons use thinner grooves and require a different ring set, so verify your piston before ordering. Standard Bore and Related Kits This set is for cylinders at the standard 3.250-inch bore; for a bored-oversize cylinder, order the matching oversize ring set. For a complete engine, a combined kit pairs two ring sets with a full gasket set and crankshaft seals, and kits that add pistons, rods, or a valve set are available for a deeper rebuild.
- This is one standard-bore piston ring set, enough for a single cylinder. Onan B-series and P-series engines are two-cylinder, so order two sets to rering a complete engine. Replaces Onan ring set 113-0314 (which supersedes 113-0189 and 113-0186); 3.25 inch (82.55 mm) standard bore.
- Fits Onan B-series and P/Performer-series 3.25 inch opposed-twin engines built prior to Spec D, including B43E, B43G, B43M, B48G, B48M, BG, and BGE (specs E through H), plus P216G, P216V, P218G, P218V, P220G, and P220V.
- For the early-style piston only. Early pistons use .078 inch (2.0 mm) top and second ring grooves with a three-piece .186 inch (4.75 mm) oil ring, and carry casting number 112-0163 or 112-0246. A quick check: a US nickel is about 2 mm thick and fits the top two grooves on an early piston. Late-style pistons use thinner grooves and take a different ring set.
- Sized for a standard 3.250 inch bore. If a cylinder has been machined oversize, order the ring set that matches that oversize (.005, .010, .020, .030, or .040) instead. Confirm your bore and the original ring part number before ordering.
- For a full engine, a combined kit pairs two of these ring sets with a complete gasket set and crankshaft seals. Kits that add pistons, connecting rods, or a valve set are also available for a deeper rebuild. A ring compressor eases assembly.