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).
Design and development strategy for the 'SS' chassis, including rollerless tappets and spring pressure.
| Identifier | ExFiles\Box 17\6\ Scan061 | |
| Date | 2nd November 1928 | |
| To WOR.{Arthur Wormald - General Works Manager} } FROM HS.{Lord Ernest Hives - Chair} To EY. } X7060 HS{Lord Ernest Hives - Chair}9/LGL2.11.28. 'SS{S. Smith}' CHASSIS. We have received the following telephone message from WW. this morning and this is being confirmed by letter:- It should be clearly understood that anything new that will make the changeover more difficult should be left off the first 'SS{S. Smith}' chassis so that existing parts which are satisfactory can be used until a later date when the new pieces will be introduced in the usual way. The great thing is to get the big move as easy as possible so that carburetter, conn. rods, lubrication and anything else which suggests itself on the present engine should not be altered unless the change is a proved one, or necessary for some other reason. Regarding the rollerless tappets. We probably can fit rollers to the tappets. We had however decided that the rollers have been the cause of some of the noise on the present tappets. We therefore consider we should persevere with the present 'SS{S. Smith}' design. It is evident that the spring pressure is the cause of the wear being different to the F.{Mr Friese} engine. We can alter the rating of the spring until this is only one-third of the pressure and also make the maximum no greater than is necessary. The simplest way is to take the present springs and shorten them until we make the present follower follow the cam to the max. engine revs., then find out how much better it is when the car is in its lowest position. | ||