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).
Study and proposal for modifying the 40/50 HP engine to an OHV configuration, using existing stock parts.
| Identifier | ExFiles\Box 180\M1\9\ img010 | |
| Date | 1st October 1921 | |
| NEPTUNE ORIGINAL. 2. To J, from R.{Sir Henry Royce} Copy to OH. " HS.{Lord Ernest Hives - Chair} " SY (if CJ. approves) X4420 RE MODIFYING 40/50 H.P. ENGINE, CONVERSION TO OHV I have studied the stock of parts for the present engine at Derby, and my conclusions are that we ought to make about 150 engines to the present design, then introduce modifications consisting of new crankchamber and cylinders, using present stock of parts (for from 300 to 400 engines) of crankshafts, pistons, connecting rods, flywheels, clutches and valves, stopping work at once on all parts not required for the first 150 engines. Apparently from the stock list, this would avoid any considerable loss of any large and expensive part. The engine proposed would not be very different in cost to the present engine, but would reduce some of the known defects of engines of the present type. We should get a better system of induction pipe, combustion chamber, less liable to detonations, detachable head to facilitate cleaning and removing of pistons, and a few other advantages which are desirable. It will be noticed also that with this policy the sum required for tool making will be considerably less, as there will not be the tools needed for the parts which remain unaltered. I think this policy is so remarkably good that I regret we have not realised its possibilities before. It does not, however, of course, fulfil all our wishes, as we had hoped to use a smaller bore and longer stroke engine, which would so reduce (Contd.) | ||