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).
Difficulties experienced with new type crankshaft dampers on 20 HP and 40/50 HP models.
| Identifier | WestWitteringFiles\S\June1928-August1928\ Scan094 | |
| Date | 19th July 1928 | |
| To R.{Sir Henry Royce} From Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} c. to BJ. Wor.{Arthur Wormald - General Works Manager} c. to E.{Mr Elliott - Chief Engineer} DA.{Bernard Day - Chassis Design} c. to BY.{R.W. Bailey - Chief Engineer} ORIGINAL Hs{Lord Ernest Hives - Chair}/Rm{William Robotham - Chief Engineer}/LG19.7.28. NEW TYPE CRANKSHAFT DAMPERS. X7010 X634 X5010 20 HP. LeC.2457. 40/50 HP. LeC.2462/2472. We have now had a considerable amount of experience on these crankshaft dampers on both cars. We have experienced one or two difficulties which are as follows :- (1) On the 40/50 with the latest type shaft having tubes in the big ends, we find that the drive as arranged acts as a very efficient centrifugal oil cleaner and gets full of deposit which affects the friction loading. We found this after 4000 miles running on 12-EX. We are now running with drain holes. With cork, which we are trying however, we may be able to get more consistent results. (2) If we want to alter the valve timing, we have to dismantle the drive; this is rather a tedious job. (3) Owing to the fact that when we stall the car on top gear at about 3 m.p.h. the angular acceleration of the crank at each explosion is very high, particularly if one cyl. momentarily cuts out, the damper under these conditions is liable to hit the stops with a metallic clonk. We can obviate this by increasing the damping, but if it did not occur we could use less friction and still get rid of our harmonics. Also, it is rather alarming to know that it may happen if the friction load for any reason decreases. contd :- | ||