Rolls-Royce 20/25 - oil pump

 

 

oil pump

 

The oil pump main components.

The original tolerances are shown below with the final figures for this pump shown in parenthesis: -

gear backlash = 0.003" (0.013")

radial gear clearance = 0.002" (0.005")

gear end float = 0.002" (0.002")

drive shaft radial clearance = 0.0005" (0.0005")

Contrary to what is stated in Haynes & Grigsby the General Arrangement drawings show that there is no paper gasket used on the bronze bodied pump.

relief valve

 

The oil pressure relief valve in pieces.  The spacers fit over the pin in the threaded cap - a maximum of 5 spacers may be used.  The correct running oil pressure is18psi at 50mph with a hot engine.

dynamo brakes

 

The two brake assemblies for the dynamo drive pinion.  The shaped fibre shoes should be a tight sliding fit in their cases.  The movement range of the shoe is restricted by the cross-pin in the slot of each shoe.

hole

 

Aperture for the brake assembly showing the drum on the back of the pinion.

brake fitted

 

Two gaskets are used on the casing; one above and one below the flange.  New shoes and springs were fitted.  The previous shoes had swollen to the point where they would no longer move in the casings.

exterior

 

The lower brake fitted and bolted down.