Abstract: A spring actuated piston pump for use in lubricating the bearings of a turbo-charger rotor, both on starting and stopping an associated internal combustion engine. The pump has a piston-and cylinder combination the piston of which is spring-urged towards the cylinder head, and there is a releasable catch arrangement operable on the piston to restrain movement of the piston towards the cylinder head when the piston is part-way between the extremes of its travel. The catch means is solenoid operated for connection to the engine starter system, so that the piston is released when the engine is started.The pump chamber is connected to the engine lubrication system and the turbo-charger bearings through suitable ducts and one-way valves, so that on ordinary operation of the engine the pump chamber is full of oil with the piston fully retracted. On stopping the engine the piston moves under the spring bias discharging oil to the turbo-charger bearings until restrained by the catch arrangement.