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).
Advantages and implementation of rollerless divided valve rockers.
| Identifier | ExFiles\Box 43\3\ Scan111 | |
| Date | 1st January 1927 | |
| To E.{Mr Elliott - Chief Engineer} RG.{Mr Rowledge} Hs.{Lord Ernest Hives - Chair} from R.{Sir Henry Royce} c. to BJ. Wor.{Arthur Wormald - General Works Manager} BY.{R.W. Bailey - Chief Engineer} RR. F.10. VALVE ROCKERS. X.3822 Re. LeC. 2363. X.4003 These are the rollerless divided rockers that have many advantages. (1) They halve the risk of an overloaded spot on the cam and pad. (2) They are unaffected by broken springs which was previously followed by borken rockers, which was not cured by strengthening. (3) This design also makes exhaust and inlet rockers interchangeable, requiring but L. & R.{Sir Henry Royce} hand. I telegraphed as follows - To Royce, Chichester. "ROCKERS GOOD LENGTHEN BOSS FOR LARGER VALVE SPRING "OR FOR SHORTER CENTRE TO AVOID ALTERATIONS APPARENTLY "BOTH SIDES REQUIRE PRESSURE LUBRICATION SUGGEST MAKING "EXPERIMENTALLY AT ONCE" Before these get far advanced you will find out any trouble they are likely to cause in the alteration. My impression is that the cam form is the next job, assuming that the modifications to permit of the use of these rockers are not insurmountable. I do not mind altering the smaller parts, but it should be arranged that the cyl. block remains the same, even if we have to be content with 1.3 dia. springs, although we have cut the bosses of the levers for clearance. Regarding the cam form every thing shews that the closing of the inlet is the limiting point, and we can give this a little more time, as I suggested recently, than the opening: this seems desirable. The idea I gave was, at your highest running speed to make the pressure on the Cam equal throughout the time, so as to give under spring control the same and max. margin of safety for a given valve spring, allowing for friction and air currents. R.{Sir Henry Royce} | ||