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).
Tests and modifications on a Bentley petrol pump to improve delivery and resolve sticking hexagon valves.
| Identifier | ExFiles\Box 27a\2\ Scan177 | |
| Date | 3rd June 1933 | |
| K2677 To E.{Mr Elliott - Chief Engineer} From Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} c. Wor.{Arthur Wormald - General Works Manager} By.{R.W. Bailey - Chief Engineer} c. Ba. Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer}1/KT.3.6.33. We have been carrying out further tests on the petrol pump for the Bentley car. We found that with the spring giving a delivery pressure of 4.2 lbs/sq.in. we were only just able to provide for the requirements of the engine at maximum speed, and in consequence there was no margin for a drop in the pump efficiency in service. We found that by opening all the ports and valve seats in the head to .312" diameter, and increasing the valve clearance from .060" to .100" we increased the pump delivery about 10 pts/hr. The two gains - (1) the stronger delivery spring, and (2) the larger ports are shown on the attached curve Hs.{Lord Ernest Hives - Chair}1034, and represents the delivery of the pump under chassis conditions except that the fuel does not pass through the carburetter float chambers and needle valves. We find that the hexagon valves at present used may be a source of trouble as a point on the hexagon is liable to stick in the suction port. We find we eliminate this sticking and do not lose any efficiency with the present drilling if we use round valves having a diameter of .475". The modified passages are shown on Hs.{Lord Ernest Hives - Chair}1035 attached. Will By.{R.W. Bailey - Chief Engineer} please instruct. Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} | ||