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).
Critical analysis of a cylindrical combustion head, valve gear, and spring design, including a blueprint diagram.
| Identifier | ExFiles\Box 23\5\ Scan031 | |
| Date | 20th December 1927 guessed | |
| contd :- -3- The combustion head is cylindrical, no attempt at inducing turbulence being made. Fig.1. illus- trates the shape of the combustion head, valve ports and valve gear. The valves are described as being made of chromium silicon alloy; the seatings are 45º. The sketch indicates the arrgt. provided for adjustment of tappet clearance; the valve cap is locked on to the valve piston, both being screwed on to the valve stem. The xxxxx valve cap and piston are drilled to take a 1/4" dia. tommy bar by means of which the adjustment is slacked off; this locking device is very poor in practice, the valve adjustment continually coming loose, also it is not possible to alter the adjustment if the valve is not on its seating as there is no provision made for holding the valve from turning. Altogether the design is extremely impractical. One valve spring per valve is used; they are conical and described as being made of Holcomb Chrome Vanadium electric furnace spring steel. The valve spring loads are given as 56 lbs. when the valve is closed and 102 lbs. when open, which gives a spring rating of 46/.343 = 103.4 lbs/in., taking the valve lift as .343", which is the figure given in the instruction book. The springs have the following particulars :- [Text from diagram] FIG:1 OIL METERING PIN VALVE CAP VALVE PISTON OIL DRAIN CHANNEL VALVE PISTON GUIDE | ||