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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).
Rectifying an overoiling complaint on a Bentley B.122.GA, including test results.

Identifier  ExFiles\Box 131\4\  scan0366
Date  6th July 1937
  
Not sent out.

To Hs.{Lord Ernest Hives - Chair} from Rm{William Robotham - Chief Engineer}/GWH.{George W. Hancock - Head Chateauroux}
C. to Rm.{William Robotham - Chief Engineer} [crossed out]
C. to Sr. [crossed out]

Levallois, France.
July 6th.1937

Mr.Lang's Bentley B.122.GA.
Overoiling Complaint.

This car is now satisfactory for oil consumption at high speeds.

It has been fitted with the latest finished R.R. cylinder block, High pressure scraper rings, pistons with bottom of skirt 3.500 dia., Main crankshaft bearings, conn. rod bearings.

The engine had to be run lightly for a day to free the pistons as it was tacky. The first oil consumption taken with an average speed of 45 M.P.H. was 625 M.P.G. After again running in a high speed test was taken.

100 miles - time 1 hr. 46 mins. Average speed 56.5 M.P.H.

(1) Oil pressure 30 lbs.
Oil used .1075 gallons = 930 M.P.G.
Engine revs 4,500 reached on several occasions.

(2) 100 miles time 1 hr. 55 mins. Average speed 52.1 M.P.H.
Oil pressure 30 - 35 lbs.
Oil used .11 gallons = 909 M.P.G. Engine revs 4,000 max.
The breather in this case was removed from the rocker cover,
a vented cork fitted to prevent splash of oil coming out.

Weather conditions hot. Average oil temp 100°C.
2nd. test carried out immediately after first.

The results of these tests have proved that for the high average speed driver on the Continent the latest pistons are necessary with the higher pressure scraper rings. This is with the large oil pump fitted. All the complaints of poor oil consumption have arisen since the fitting of the large oil pump, which, with good bearings maintains an oil pressure of 35-40 lbs. at maximum speed with hot oil. (Approx. 100°C.)

In either case that has been dealt with the cylinder wear did not warrant high oil consumptions, taking the average wear of cylinder bores in service that has not given any trouble with oil consumption. It is highly probable that with the new

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