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).
Final specification and performance notes for a Stromberg carburetter on car 21-C-IV (Large Bore).
| Identifier | ExFiles\Box 20\9\ Scan081 | |
| Date | 15th January 1936 | |
| To Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} c. to Hs{Lord Ernest Hives - Chair}/OTS. X1033 Hs{Lord Ernest Hives - Chair}/GR.{George Ratcliffe}3/KW.15.1.36. 21-C-IV (Large Bore). Final specification of Stromberg carburetter DA{Bernard Day - Chassis Design}-42, as fitted to suit larger bore manifold and turbulent head. Choke 1¼" dia. Main metering jet .062. Bypass metering jet .029 (drill size) Main discharge tube with single feed hole 56. Idle tube jet 64. Pump jet 70 and set on maximum stroke. Air bleed 70. Seating .130. Petrol level .625", Petrol drain is fitted with .312" dia. alum. ball taken off the Packard. Diameter of pump link split pin increased from 1/32" to 1/16". Ignition timing advanced to 20° B.T.D.C. for performance. No detonations on Pratt's Ethyl petrol. Slight detonations on Shell petrol at low speeds. The radiator shutters on this car can be kept closed if high speeds are reached before the thermostat operates. Sudden high temperatures and boiling are the result. Thermostat unit probably failing in radiator. Maximum speeds recorded on Six Hills - 77/79 m.p.h. Hs{Lord Ernest Hives - Chair}/G.Ratcliffe. | ||