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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).
Engine modifications, bearing types, and associated costs for an R.20 service.

Identifier  ExFiles\Box 114\3\  scan0075
Date  20th September 1938
  
2.
Rm{William Robotham - Chief Engineer}/GWH.{George W. Hancock - Head Chateauroux}21/N.20.9.38 Cont'd.{John DeLooze - Company Secretary}

To freshen your memory, the following were the memos:-

Rm.{William Robotham - Chief Engineer}1/R.7.7.37 item C. at R.20.

Removing crank, drilling additional holes, grooving intermediate bearing, and fitting new big ends and large oil pump.

Paragraph 5.
If for any reason whatever a crankshaft is removed from an engine it should have the additional holes drilled in both the pins and journals.

Rm.{William Robotham - Chief Engineer}16/MH.{M. Huckerby}28.10.37.

Big end bearings changed and large oil pump.

At 20,000 miles or when an R.20 is carried out, the opportunity should be taken of putting a groove in the lower half of all the intermediate bearings. If when this modification is carried out the big end bearings show signs of breaking up they should be replaced by new white metal bearings as hitherto. It is not necessary to fit a larger oil pump to 3½ litres which are treated in this manner.

If and when the instructions are carried out to Rm{William Robotham - Chief Engineer}'s memo of the 7.7.37 paragraph 5, the large oil pump is necessary although the bearing clearances are less.

We presume that costs are one of the reasons why white metal is used. This is a fallacy, providing the oil pump is not dealt with.

The actual cost to Depots for bearing shells are:
Halls (pair) 10/2d.
White metal (pair) 9/11d.
It costs three hours more labour to fit white metal for six rods than Halls metal. The actual cost of an oil pump complete with three new pipes is £2-9-6d. (reference E.750 invoice).

In conclusion the majority of Owners pay for new bearings at an R.20.

GWH.{George W. Hancock - Head Chateauroux}
  
  


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