Piston Ring Set for the 3.9 litre Rover V8, supplied at standard size and covering one piston - eight sets are required to do a complete engine. The rings perform three distinct jobs in the cylinder bore: they seal the combustion chamber so that compression and combustion pressure act on the piston rather than escaping into the crankcase, they conduct heat out of the piston crown into the bore wall and on into the coolant, and they meter the oil film left on the bore so that the cylinder is lubricated without oil being drawn into the combustion chamber. Worn, glazed or gummed rings present as high oil consumption, blue exhaust smoke, low or uneven compression readings, and crankcase pressurisation. Rings should only be fitted to a bore that has been measured and, where required, honed to restore the crosshatch finish. Check the ring end gaps squared up in the bore before assembly and stagger the gaps around the piston as specified rather than aligning them.
