similarly fuel is conveyed from outlet check valve 44 by a fuel line 62 which includes a coupling means 63 adapted to engage the upper end member 23 to provide a fuel tight connection so that fuel is provided by the pump 40 to injector means 21 the fuel in tank 60 is preferably a liquid such as diesel fuel and is substantially uncompressible thus operation of pump 40 does not compress the fuel any substantial amount but simply displaces and pressurizes it and thus causes it to exert a pressure on the injector means 21 as indicated the connection between crankshaft 14 and cam 54 may be fixed so that the same phase relationship always exists between them in many instances however it will be desirable to vary this phase relationship and thus the point in the engine cycle where fuel injection and combustion takes place in response to the speed of the engine this may be accomplished by interposing in the connection between crankshaft 14 and cam 54 a planetary gearing arrangement 70 including an input gear 71 driven by the crankshaft 14 an output gear 72 driving cam 54 and an intermediate planet gear 73 gears 71 and 72 are bevel gears arranged coaxially gear 73 is also a bevel gear with its axis normal to the axes of gears 71 and 72 and movable in an arc about the axes of gears 71 and 72 when the axis of gear 73 remains stationary the phase between input and output gears 71 and 72 is constant movement of the axis of gear 73 will change this phase relationship and thus the point in the engine cycle at which pump piston 46 will be operated to inject fuel into the engine the positioning.