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).
Cylinder bore expansion tests for Spectre and J.III Unit Centricast Iron Liners.
| Identifier | ExFiles\Box 103\4\ scan0128 | |
| Date | 1st February 1935 | |
| (2) SPECTRECodename for Phantom III (2) - CENTRICAST IRON LINERS Comparisons of cylinder bore expansion figures obtained with and without the heads in position (see charts 3 & 4) shew that in the former case, expansion is considerably greater adjacent to the crowns, the increase in some cases being .0015" (Actual differences are shewn on chart (4) in Green ink). Further tests shew that when the liners are detached from Cylinder Blocks, expansion is uniform in all positions. These tests were made with Centricast Iron and Austenitic Steel Liners. J.III. UNIT - NIMOL IRON LINERS E.{Mr Elliott - Chief Engineer} 57011 On this unit expansion of the bores at the crowns is similar to that of the SpectreCodename for Phantom III viz .002-.003" (see chart 2). The striking difference noticeable is the higher expansion of the skirts at right angles to the Crankshaft. This is probably due to a greater length of the skirt being unsupported, than on SpectreCodename for Phantom III type Liners. Check of liners before being fitted to the Cylinder casting indicates that there is a certain amount of distortion which can be attributed to the method of holding during the grinding operation and if it is considered that the inaccuracies shewn on the charts are liable to cause piston knocks the only alternative is to hone to size after the liners are fitted to the cylinder castings. We are arranging to carry out this test on one of the SpectreCodename for Phantom III Units, for the purpose of obtaining comparative figures with the liners which are ground before being inserted. The following charts are attached:- (1) Expansion figures for SpectreCodename for Phantom III Liners prior to assembly. (2) Expansion of J.{Mr Johnson W.M.} III. Liners after insertion, with cylinder heads in position. (3) Expansion of SpectreCodename for Phantom III Liners in Crankcase, with cylinder heads removed. (4) Expansion of SpectreCodename for Phantom III Liners in Crankcase, with cylinder heads in position. continued. | ||