Abstract: A dual planar compression ring arrangement where first and second compression rings for fitting into a single groove of a piston coaxial with and abutting one another. The first ring has a flat surface provided with an axial projection for fitting into the gap of the second ring to prevent rotation of the ring gaps towards one another. The gap in the second ring is contoured to permit full closure of the second ring upon itself around the projection.

Abstract: The specification describes a distributor apparatus provided with a plurality of distributor valve arrangement in a circular pattern and including valve plungers. The distributor apparatus includes a rotary distributor cam provided with a single distributor lobe for orbiting in the circular pattern and for moving the valve plungers in succession from a non-distributing to a stationary distributing position. The cam lobe has a planar face for holding the valve plungers in the distributing position throughout the entire delivery stroke of a pump unit plunger metering and pumping fuel to the distributor apparatus.