Vc is 2s yes? This engine does not run an oil ring as such. 2 compression rings with the lower using a ring expander to apply more force to the cylinder wall increasing compression and risk of blow by. It is however lubricated by the oil fuel mix from the crankcase gases. Im unclear what you mean by excess oil? Its a 2 stroke what oil goes in gets burnt in the cycle. If you mean oil in the crankcase then that is whats left overtime when the fuel and oil seperate or when fuel vapours left in the crankcase when the mower is shut down evaporate.....The reason people dont use the expander is that some rings brands run identical ring sizes so do not require nor can you fit the expander. The other brands have one ring slightly smaller for use with the expander. You will sometimes see a small/fine stripe on one ring which denotes the thicker one. the other reason is....The fitter was lazy or didnt know what he was doing....Hope that makes sense...Im just curious about excess oil. wxcessive oil CONSUMPTION in a 4 stroke will definately use more oil and probably sieze the engine if they wernt fitted. But a 2s doesnt work this way:)