Standard bore piston ring set for Kohler KT17, KT19, M18, M20, MV16, MV18 and MV20 twin cylinder engines, replacing Kohler part number 52-108-09-S. Bore is 3.125 inch, 79.4mm. One set covers one cylinder, so a twin cylinder engine requires two sets. The larger engines in this family gain their displacement through a longer stroke rather than a larger bore, which is why a single ring set covers the whole range. This is the standard size set. If the cylinder has been bored oversize, order the matching .010, .020 or .030 set instead. Rings will cure oil consumption and blowby on a bore that is still round and within taper limits, but they will not seal against a scored or glazed cylinder, so measure before ordering.
- FITS KOHLER KT17, KT19, M18, M20, MV16, MV18 AND MV20 twin cylinder engines. Replaces Kohler 52-108-09-S. All seven of these engines share a 3.125 inch bore, which is 79.4mm. The bigger models make their extra power with a longer stroke, not a wider bore, and that is why one ring set spans 16 through 20 horsepower.
- ONE SET, ONE CYLINDER. Kohler packages these rings per piston. A twin cylinder engine needs two sets. This is the single most common ordering mistake on this part, and it is worth getting right before the engine is in pieces on the bench.
- STANDARD BORE. This set is for a cylinder still at 79.4mm and within service limits. If the block has been bored, Kohler lists .010, .020 and .030 oversize sets and you need the one that matches your finished bore. Measure the bore before ordering rather than assuming the last person left it standard.
- WHEN RINGS ARE THE ANSWER, AND WHEN THEY ARE NOT. Rings fix oil consumption and blowby on a cylinder that still has a good crosshatch and is within taper limits. If the bore is scored, glazed hard, or measures out of round, fresh rings will not seal against it and the oil burning comes right back. Check the bore with a gauge before you buy rings.
- WHILE THE ENGINE IS APART. Hone the cylinder to give the new rings something to bed against, check the rod bearing clearance, and fit a new head gasket and valve stem seals. Set the ring end gaps to your engine manual with the ring squared in the bore, and stagger the gaps around the piston on assembly.