Abstract: A distributor installation tool for synchronizing valve and ignition timing and for priming an oil pump. The tool is formed having an elongated structure portion that is similar to a gasoline internal combustion engine'distributor shaft and having a head structure that facilitates rotational engine mounting and which provides a marker portion for indicating the relative ignition firing position corresponding to a piston being at top dead center during the compression stroke. The tool finds particular application during rebuilding of an engine where the tool is installed on the engine during adjustment of the intake and exhaust valves. In this particular application, the engine's ignition firing order is tracked by the tool's marker portion during valve adjustment, and other subsequent engine crankshaft movement, prior to installation of the engine's distributor assembly. The tool's marker portion provides a precise mark for installing the distributor shaft and rotor.