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 examination of a rough engine from chassis B.100.HK, detailing crankshaft measurements, hardness tests, and proposed modifications.
| Identifier | ExFiles\Box 146\1\ scan0193 | |
| Date | 14th February 1938 | |
| Iles 1245 Swett To Bentley Motors Ltd. Derby.................. Copy to .............. Rm.{William Robotham - Chief Engineer} Levallois Sr/VA3/ET.14.2.38 Re: CHASSIS B.100.HK{Col. T. Harker - Sales} - Mr. P. MICHELIN (Total mileage: 15.640 miles) The above car has been sent to us for attention to the engine, which is very rough. We have dismantled the engine for examination and modifications and find the measurements of the crankshaft to be as follows: I 2 3 4 5 6 7 Maximum dia- meter of main journals...... 2.2475" 2.2465" 2.247" 2.247" 2.245" 2.247" 2.247" Minimum dia- meter of main journals...... 2.246 2.245 2.245 2.245 2.245 2.2455 2.246 Ovality....... .0015 .0015 .002 .002 .001 .0015 .001 Crankpins..... 1.9965 1.9985 1.9985 1.9975 1.9985 1.9985 Bow at centre : .004" Owing to the wear and ovality that have taken place on the main journals of the crankshaft, we suspected that the shaft was "soft". We therefore sent it to Messrs. Aubert & Duval and they have, at our request, carried out a hardness test on N° 1, 4 and 7 main journals and they have informed us that the hardness figure is 702/707 Vickers/Brinell. This appears to us to be a good average for this type of material. We should mention that the main bearings of this car are in very poor condition and will have to be changed. Bearing in mind paragraphs 5 and 6 (re Crankshafts) of page 1 of your memo By6/G.1.2.38 and unless we hear from you to the contrary, we propose to have the main journals of the crankshaft re-ground to .010" undersize and then have the shaft renitrided, also bearing in mind the contents of your memo By2/G.6.II.36 "Nitrided Crankshafts" "re: Method of recovering worn shafts". Sr/VA. P.S. Upon dismantling the cylinder Block we found that Nos 1 & 5 bores are cracked at the mouth. We will send you a report and sketch to-morrow. | ||