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).
Oil temperature regulator (cooler) failures on PH.III cars 3-AZ-88 and 3-AZ-98.
| Identifier | ExFiles\Box 131\1\ scan0248 | |
| Date | 1st December 1936 | |
| 1114 To Hs.{Lord Ernest Hives - Chair} from Rm{William Robotham - Chief Engineer}/Std. c. to E.{Mr Elliott - Chief Engineer} c. to By.{R.W. Bailey - Chief Engineer} c. to Da.{Bernard Day - Chassis Design} c. to Mx.{John H Maddocks - Chief Proving Officer} Rm{William Robotham - Chief Engineer}/Std.11/AP.1.12.36. REPORT ON OIL TEMPERATURE REGULATOR (COOLER) FAILURES ON PH.III. CARS 3-AZ-88 and 3-AZ-98. The oil coolers on the two above mentioned cars failed recently and were returned to us for examination. They were tested and found to leak at the points shewn on the attached sketch. They were examined and appeared to be quite clean internally, one of them - that off car 3-AZ-88 - was tested for back pressure against a new standard cooler and within the limits of Experimental error gave the same back pressure as the standard cooler, indicating that no blocking up of the oil ways had taken place. The mileages were respectively 3-AZ-88 - 926 miles and 3-AZ-98 - 376 miles. Examination of the coolers also revealed that they were fitted to the engines before the production pressure test rig was operating - they commenced to test all Production coolers from about the 10th cooler received onwards i.e. Nos. E.1. to E.10 - and each cooler is stamped if it passes the test - the coolers which failed were not stamped, and were Nos. E.4. and E.8. The pressure test which we specify is 200 lbs/sq.in. with oil at normal atmospheric temperature and 150 lbs/sq.in. at a temperature of 130°C. Each cooler is tested by Messrs John Marston Ltd., under these conditions and is again tested by us under the cold condition - i.e. 200 lbs/sq.in. Since Production have been testing these coolers there have been a varying percentage of rejects due to leaks - this percentage at times has been of the order of 33%. However, Messrs Marston Ltd. have improved and are still improving their production methods with a view to eliminating all rejects - the percentage with the last delivery was 3.1%. In view of these facts we think it highly probable that some of the coolers which are fitted to engines before Production's pressure test was operating may be faulty and therefore these coolers should be changed and replaced by tested ones. We have yet to experience a failure in service with a cooler which has satisfactorily passed the Production pressure test. continued. | ||