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).
The expansion of Goshawk 11 exhaust valves to determine required tappet clearance.
| Identifier | WestWitteringFiles\K\September1923\ Scan1 | |
| Date | 1st September 1923 | |
| R.R. 493 (40 H) (SL 42 12.7.23). J.H., D.{John DeLooze - Company Secretary} ORIGINAL EXPERIMENTAL REPORT. COPIES TO: (RCJ) Sd.W. (WER) (By) (E) (Da{Bernard Day - Chassis Design}) (EP{G. Eric Platford - Chief Quality Engineer}) Expl. No. 4226 4238 REF. Hs{Lord Ernest Hives - Chair}/1LG1.9.23. OBJECT OF TEST. To find the expansion of Goshawk 11. Exhaust Valves under running conditions, in order to find the tappet clearance required to keep the valves seating. TESTER. A.{Mr Adams} J.{Mr Johnson W.M.} Lidsey. CONDITIONS. Tests carried out on Engine S-Goshawk-11- standard cylinder head and pistons - i.e. standard compression ratio. All tests run under conditions that would cause exhaust valves to receive maximum heat. SUMMARY OF TEST. By means of a special measuring device bolted to the cylinder head, it was possible to measure the absolute valve expansion. Standard Tulip shaped Valve (15° seats) Expands .010". Tulip shaped Valve (45° seats) Expands .006". Except for the angle of the seats, the above two valves are identical; thus the head and the stem of the one will expand the same amount as the head and the stem of the other (all outside conditions being equal). The difference in the total expansions can only be caused by the head of the 45° valve rising higher on its seat, on expansion, than the head of the 15° valve. Thus as both stems expand equally, the absolute expansion of the 45° valve must be less than that of the 15° valve. contd:- | ||