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From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Top over-oiling experiments for the Phantom III, detailing work on inlet valve guides and oil drain pipes.

Identifier  ExFiles\Box 96\1\  scan0073
Date  9th March 1937
  
361

Mx.{John H Maddocks - Chief Proving Officer} from Rm{William Robotham - Chief Engineer}/Swdl.{Len H. Swindell}
Rm{William Robotham - Chief Engineer}/Swdl.{Len H. Swindell}8/R.9.3.37.

PHANTOM III - TOP OVEROILING EXPERIMENTS.

The following is a description of the work carried out on 3.AZ.170 Leonard's car, and which we understand you are going to carry out on four of your production chassis.

Inlet Valve Guides.

Remove the inlet guides and replace by new ones reamed to give a diametrical clearance on the valves of .0015 - .002.

Our experience of 3.AZ.170 shows that if an inlet guide is slack in the head or the surface of the taper reamed hole is not good, then oil gets down the outside of the guides. Either of these troubles necessitates oversize guides (outside dia) and oversize reamer to clean up the surface of the taper hole in the head.

It is essential that the guides are correctly fitted into the head with the right amount of interference fit. A pilot to be used when the new guides are fitted in order that the valves will remain true to their seats and only necessitate lapping in.

Oil Drain Pipes.

The drain scheme is outlined on the attached drawing LeC.4724 on which we have pencilled the alterations as carried out on 3.AZ.170. This consists of the following:-

(1) 6 - 1/4 drain pipes on each cylinder head taken from the small recess at the base of each inlet valve spring.

(2) The unions which are standard for 1/4" pipe are screwed into the head as low into the recess of the spring pockets as possible
  
  


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