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).
The testing of DeJon Ignition heads and coils, detailing a bench test and a road test on vehicle MX-2.
| Identifier | ExFiles\Box 53\3\ Scan129 | |
| Date | 5th April 1927 | |
| RE: DE JON IGNITION Two sets of DeJon Ignition heads and coils with automatic advance of 22º from 500 to 2000 RPM, were tested as follows: A.{Mr Adams} Bench test B MX{John H Maddocks - Chief Proving Officer}-2 Test A.{Mr Adams} A pair of heads and coils were run on the bench for nine hours daily at 50 MPH and up to date have run for 1500 hrs. equal to 75,000 miles. The 6 sparks were made to jump thru an air gap, 5 jumping 3/16s and one 5/8". Beyond regular lubrication and a brief weekly inspection, no part has been adjusted in any way. The contact points, originally set with a .017" gap, have closed down to .010 showing only a small amount of wear of the rather fragile looking Bakelite rubbing contact on the contact maker arm. This contact is held in place by one rivet only and has not worked slack on any of the 4 parts tested. The possibility of this happening was raised in Mr. Nadin's memo on this subject of April 5th, 1927 (NaEB4527(. Test B. A similar set fitted to MX{John H Maddocks - Chief Proving Officer}-2 has run 11,000 miles, mostly at high speed without being touched in any way beyond regular, more or less, lubrication. The contacts were originally set with a gap of .018 and are now .018 for one and .016 for the other, showing practically no trace of wear for the Bakelite rubbing contact on the contact maker arm. The contacts themselves do not require attention for additional running. The carbon brush on center of distributor rotor is practically unworn, and the bass distributor contacts are only slightly discolored. The spindle shows no wear and the bushes, which have an indented surface and appeared rather poorly finished when new, are still a close fit on the spindle. | ||