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).
Comparative tests on engine running-on issues, spark plugs, and valve types.
| Identifier | ExFiles\Box 162\3\ img208 | |
| Date | 11th September 1940 | |
| Rm{William Robotham - Chief Engineer}/CTS.{C. Trot Salt - Carburation}2/ST.11.9.40. - 2 - 2. We were to have carried out a direct comparative test on a head removed from a car, as we do not get any appreciable carbon accumulation on the test-bed. 3. We have found that, if water is sprayed on the exhaust valves, there is no running on after switching off. 4. We have only used Champion plugs for B.60 and B.80 on the bed; these are N.8, NA.{Mr Nadin}8 and NA.{Mr Nadin}10. a.{Mr Adams} For full throttle running: NA.{Mr Nadin}10. b. For good slow running: N.8. Although N.8 and NA.{Mr Nadin}10 show signs of pre-ignition, there is no measurable difference between these and NA.{Mr Nadin}10 for the running on time after switching off. Evidence submitted from road tests is confusing; for instance on the test-bed no one would dispute the fact that exhaust valve temperature is a primary controlling factor. From this one would expect that sodium cooled valves would show some difference on the road. It has been said that sodium cooled valves operating upside down may not work, but it has not been proved. In memos Rm.{William Robotham - Chief Engineer}10/ML.4.6.40 and Rm.{William Robotham - Chief Engineer}9/ML.29.5.40, the evidence can be separated as follows: a.{Mr Adams} Cars which "run on":- 9.B.V and 4.B.50. b. Cars which do not:- 11.B.V and 30.G.VII. It should be noted that, from Rm{William Robotham - Chief Engineer}/RC.{R. Childs}'s latest report, the in-ference is that 4.B.50 is no longer "running on" (as it was previously), al-though fitted with plugs which have been turned down as causing this trouble on 9.B.V. Finally, separating the above four cars into two good and two bad, we have:- a.{Mr Adams} (9.B.V with solid valves. (4.B.50 " sodium filled valves. b. (11.B.V " sodium filled valves. (30GVII " solid valves. It can be concluded that we know little about this problem and can start in seriously some time with a clean sheet. Rm{William Robotham - Chief Engineer}/CTS.{C. Trot Salt - Carburation} | ||