Importance

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Abstract

A lubrication and breather system for an engine that is generally adapted for use as either a vertically-oriented crankshaft-type engine or a horizontally-oriented crankshaft-type engine. The crankcase has first and second bearing bosses supporting first and second journal portions of the crankshaft. The second bearing boss lies above the first bearing boss when the engine is of the vertical-type. The system includes a cap that is secured over the second bearing boss and cooperates with the second bearing boss to define an annular chamber for receiving splashed oil produced in the crankcase. The cap has a plurality of ribs formed thereon that reduce an amount of oil, which is entrained in the blow-by gas, sent from the annular chamber to the breather chamber. The second bearing block includes an oil feed hole, a plurality of oil sumps, and a plurality of oil return holes, with the oil return holes being of relatively smaller size. Each of the oil sumps is associated with one oil return hole. A volume of oil ordinarily remains in the oil sump to limit entry of blow-by gases into the annular chamber via the oil return holes.

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First Claim