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).
Car performance, covering engine misfires, handling, and potential design improvements.
| Identifier | ExFiles\Box 17\3\ Scan170 | |
| Date | 31th December 1927 | |
| Hs.{Lord Ernest Hives - Chair} E.{Mr Elliott - Chief Engineer} from R.{Sir Henry Royce} c. to BJ. Wor.{Arthur Wormald - General Works Manager} DA.{Bernard Day - Chassis Design} c. to SG.{Arthur F. Sidgreaves - MD} BY.{R.W. Bailey - Chief Engineer} LHS.{Lord Herbert Scott} C. +7430- R1/M31.12.27. EAC.7. X.7770 X.7410 X.7430 Regarding misfires, these have been cured on the magneto by a fresh set of plugs set at .020". One must conclude that one of the following was the cause : (1) Oxidised points on plugs. (2) Two small safety gap on magneto. (3) That .025 is too wide for 5 to 1 compression. They mostly occured at 10 m.p.h. full throttle. On this short journey we could not find if pre-ignitions really exist, and it may be misfires on both ignitions for one of the above reasons. Taking the whole car we think it a decided improvement in riding, steering, acceleration, and the lower, longer and general appearance. The roof seems amply high, but probably the bodywork is heavier than the Barker-Beatonson of last year, and it seems that what we have gained on the chassis - say 200 lbs. - has been lost on the body, but we have glass between driver and rear, and two good occasional seats instead of one. Altogether we are extremely pleased with the car, but it detonates at low speed with French petrol at this 5/1 compression. You will remember it was intended to use 4.5 to 1, but a faulty casting sent me away with 5/1. Torque reaction, and overrun, seem much better than one would expect. If we had not hopes of something better in EAC.10 we should recommend going on with these EAC.7 improvements. One is much struck with the better appearance due to parts we have made to help the coachbuilder, who cannot make the same kind of thing in their numbers, or by their resources. I mean : (1) Wheel carrier (2) 5 grouped instruments. (3) Luggage carrier. (4) Wing stays. (5) Battery in frame. One will remember the days when coachbuilders supplied petrol tanks, step irons and many things now sent out with the chassis. These parts were heavy, costly, unreliable, so we must look forward to fitting well tested standard parts made in quantity where-ever possible. Taking the floorboards up, the chassis has an improved appearance, but we hope still better with EAC.10. contd: | ||