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).
Exhaust valve seat angles, burning issues, and the effects of valve clearances on engine performance.
| Identifier | Morton\M22\ img174 | |
| Date | 27th December 1922 | |
| [HANDWRITTEN PENCIL] EXH VALVES SEAT ANGLES, BURNING 40/50 GII [STAMP] ORIGINAL [HANDWRITTEN PENCIL] CLEARANCES [STAMP] Hs{Lord Ernest Hives - Chair} DEC 29 1922 TO HS.{Lord Ernest Hives - Chair} FROM R.{Sir Henry Royce} c. to CJ. BJ. [Struck through] c. to FN. WOR.{Arthur Wormald - General Works Manager} [Struck through] c. to DY.{F R Danby} HM.{Capt. W. Hallam - Head Repairs} [Struck through] c. to OX. LF. [Struck through] RE. [STAMP: RECEIVED] 40/50 VALVES. You will remember that I suggested that possibly valves were not living so long because we had altered the angles of the seats. We want you as quickly as possible to prove to us whether the angle of 15° is definitely worse than 30°, and whether there is any difference between 30° and 45°. Naturally we hope and expect that you will be able to get good results with 30°, but we fear that 15° is too flat, the valve being too susceptible to distorsion. In conjunction with this matter we believe that the real cause of the trouble we have lately experienced with valves, is the want of wisdom, in setting them too closely. This view has been supported by 2 or 3 instances namely, Mr. Evernden's Rover, Mr. Stent's enquiries of a R-R owner, the Goshawk driven here by Mr. Rowledge, which failed directly after readjustment, and my own impressions generally. Our Goshawk here was run very successfully and quietly with six thous. clearance, and was increased to ten thous., to find out how noisy it became, but even with this clearance it is still very quiet, and the gas tightness seems to be improving. R.{Sir Henry Royce} | ||