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).
Technical memorandum discussing issues with crankcase oil level dipsticks and oil leaks from rocker cover joints.
| Identifier | ExFiles\Box 124\1\ scan0272 | |
| Date | 28th November 1939 guessed | |
| -2- All B.80 units in chassis are fitted with these distance pieces. (2) Crankcase Oil Level Dipstick. The position of this is such, that when oil is poured into the crankcase through the filler, it runs down the dip stick, giving an inaccurate oil level reading. The dip stick has to be wiped clean several times before an accurate reading can be obtained as it takes some little time for the oil filler to drain. We would suggest that the oil filler and dip stick be placed in separate positions on the crankcase. (3) Oil leak from rocker cover joint. This is caused by displacement of the joint washer due to contraction, so breaking down the oil seal. Wraith and Bentley rocker covers have a groove machined to retain the washer, so preventing contraction. B. 60 and B.80 not having this groove, have plain faces with external lip which prevents the joint washer from coming outwards, while there is nothing to prevent it from going inwards. There is a difference in the machining operation of these two types of covers. The B.60 and B.80 covers are milled with a 1.000" or 1.500" cutter, whereas the groove in Wraith and Bentley are milled with a small pencil cutter, which is a more delicate operation and takes longer to do. The question of time between these two operations has therefore to be considered. A scheme ECD.1526 (McStay's print) shows metal strips fitted inside the rocker cover, these being in sections to clear push rods. This scheme caters for dural push rods, whereas steel rods are now fitted. Rate of expansion with dural rods being unsuitable. The steel rods having approximately .060" more radial clearance from the rocker cover edge. This factor | ||