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).
Customer complaints of uneven slow running caused by the autovac system on Silver Ghost cars.
| Identifier | WestWitteringFiles\N\July1925-September1925\ Scan14 | |
| Date | 4th July 1925 | |
| R.R. 493A (50H) (D.B. 175 25-9-24) J.H.D. EXPERIMENTAL REPORT. Expl. No. REF: Hs{Lord Ernest Hives - Chair}2/L04.7.25. C To R.{Sir Henry Royce} from Hs.{Lord Ernest Hives - Chair} c. to CJ. BJ. c. to RG.{Mr Rowledge} E.{Mr Elliott - Chief Engineer} c. to DA.{Bernard Day - Chassis Design} EY. c. to H.{Arthur M. Hanbury - Head Complaints} RP. c. to Wor.{Arthur Wormald - General Works Manager} RE: AUTOVAC. Y3579 We have received several complaints from customers of uneven slow running. It has been proved that the unevenness occurs periodically at 10 m.p.h. every 1 1/2 mins., this action coincides with the action of the autovac. The unevenness occurs when the suction is exhausting the autovac. The trouble does not occur above 18 to 20 m.p.h. So far, the only complaints which have been brought to our notice have been on the Silver Ghost type cars. Tests show that the unevenness is caused by an over-rich mixture. The action of the autovac is identical on the 20 HP. and on the Phantom. The reason we think why we have not received any complaints on the 20 HP. is due to the fact that any slight unevenness in the running of the 20 HP. is not so obvious to the driver as in the case of the Silver Ghost. With the Silver Ghost, the least unevenness produces 'chunking' in the drive. It can also be proved that if the accelerator is pressed at the moment when the engine is running unevenly due to the over-rich mixture, bad missfiring and chunking in the drive will take place. We have tried other types of autovac. The 'Weyman' contd :- | ||