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).
Issues and modifications for distributor head D4.403, including the rotor and contact lever.
| Identifier | ExFiles\Box 168\3\ img071 | |
| Date | 13th April 1939 | |
| 6119 To By c. to By/RD. Km/KC.11/JH.13.4.39. Distributor to T.O.P.D4.426. Distributor Head D4.403. The original distributor had the Lucas type location, it was found that we could not work to fine enough limits, and for this reason we have gone back to the spigoted head as used on production. On our first bench test the head was badly sooted up due to poor ventilation. Opening out the ventilation holes from 1/4" to 3/8" had apparently cured the trouble. Further tests for this defect are being completed. No further signs of this trouble have been experienced on road tests. Rotor. In the original scheme the blade was riveted to the bakelite rotor by means of rivets, the heads of which were open to the underside of the distributor. Endurance test on the bench proved that these were effected by corona discharge. An alteration has now been issued wherein the blade is fastened by means of inserts moulded in the bakelite. The rotor blade is also to be nickel plated. Flinging of the contact lever. Flinging occurred with this type of distributor at approx. 4,200 engine revs. However, rig tests, reported in our memo Km/KC.15/JH.12.9.38. show that this may be eliminated completely by :- (1) The use of the Lucas type finger to DCD.703, in co-operation with the new type cam to L4.713. (2) The use of the Wraith type finger fitted with the longer Bentley type earthing strip, in co-operation with the new type cam to D4.718. If as in (2) but using the standard cam to D4.406, flinging occurs at 4,500 engine r.p.m. however, as this is above the working engine speed no trouble will be experienced. Cont'd.{John DeLooze - Company Secretary} | ||