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).
Specifications for engine cams, springs, valve timing, and the oiling system.
| Identifier | ExFiles\Box 137\4\ scan0013 | |
| Date | 1st June 1929 guessed | |
| contd :- -3- The cams are fairly wide, namely .750", and the base-circle dia. is 1.225". The exhaust cams have a slight dwell, but the tip radius of the inlet cams is only 3/32"; no appreciable wear has taken place. The average spring loads of 4 springs are : 53 lbs. valve closed and 84 lbs. valve open. The lift curves and timing are as shown on fig.3. Particulars of the springs are given on fig.1. They have 2 complete coils closed at each end, instead of only one as in RR. and other firms' practice for closed ended springs. The spring has 10 complete coils of wire (overall thickness) yet calculation from the observed rating shows that only 5 1/4 coils are effective. The makers state the timing with .008" clearance is : I.O. 6º A.T.D.C. E.O. 42º B.B.D.C. I.C. 46º A.B.D.C. E.C. 8º A.T.D.C. The discrepancy in the inlet timing we observed may therefore be due to the fact that we had .005" clearance during our test. This engine has a very bad carburetter roar. ENGINE OILING SYSTEM. The oil pressure is maintained at 25/30 lbs/sq.in. with an adjustable relief valve. The oil is fed to the top halves of the bronze-backed whitemetal main bearings through drilled ways in the cast iron crankcase. There are grooves .200" wide in the top halves, embracing an arc of 90º. contd :- | ||