The Wartsila 64 engine uses a fuel pump with two plungers and two barrels with common suction and discharge. The plunger for controlling the start of injection has a helix in the top of the plunger, while the plunger for controlling the end of injection is a conventional scroll type fuel pump plunger.

Both plungers are operated by the same cam. As they move upwards in their respective barrels injection will not start until the helix on the timing plunger has covered the spill port. This point is controlled by rotating the plunger in the barrel by means of a rack and pinion.

The plunger has a helix machined into it which also forms a vertical groove and an annular groove at the base of the helix. The barrel is located in the pump body which has spill ports, connected to the suction side of the pump, drilled so that they are above the top of the plunger when the cam is on the base circle. The plunger is keyed to a sleeve which has a gearwheel machined into it. The pinion meshes with a rack which can rotate the 8N7005 plunger relative to the barrel. The rack is connected to the engine governor.

The MAN B&W 32/40 engine has a separate camshaft for the fuel pumps that can be advanced or retarded as the engine is running. The final drive gear on the timing gear train has an internal helically toothed sleeve bolted to it. The gear wheel and sleeve can be moved axially by means of a hydraulic piston. The toothed sleeve meshes with a matched helical gear fixed to the camshaft.

The camshaft is fixed so that it cannot move axially. Therefore as the sleeve moves up and down controlled by the hydraulic piston, the fuel pump timing is advanced or retarded.

The camshaft for the inlet and exhaust delivery valves utilizes two different profiles for economy and full power operation. The camshaft can move axially from one set of cams to the other whilst the engine is running similar to the method used for reversing the engine direction as shown on the camshaft page.