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).
Recommendations for Simplex ring fitments on Rolls-Royce and Rolls-Bentley pistons.
| Identifier | ExFiles\Box 87\2\ scan0226 | |
| Date | 15th August 1936 | |
| X236 For the attention of Mr.Blackith. Copy to Mr.Noble. With reference to the two pistons from Messrs. Rolls Royce, Mr.Noble stated that the split skirt piston was used in the Rolls Royce engine and the Aerolite piston in the Rolls-Bentley engine. Based on this differentiation the following Simplex fitments are recommended: Rolls-Royce Piston - Split Skirt.- A 3½" x 1/8" x 5/32" Simplex Ring should be fitted in the middle groove. This groove at present is 3/32" wide and has a root diameter of 3.221". The groove should be widened to 1/8" and deepened to a root diameter of 3.3/16". It might be preferable to widen the oil holes in the relief. These holes are at present 3/32", and in the case of bad over-oiling it would be wise to widen the holes to as much as 5/32". A standard Compression Ring should be fitted in the top ring groove, and a Superslot Ring in the third ring groove. Rolls-Bentley Piston - Aerolite.- A 3½" x 1/8" x 5/32" Simplex Ring should be fitted in the second groove. This groove at present is 3/32" wide with a root diameter of 3.217". The groove should be widened to 1/8" and deepened to a root diameter of 3.3/16". A Compression Ring should be fitted in the top ring groove, and a Superslot Ring in the third ring groove. The provision made for draining does not appear to be adequate, and we suggest increasing the number of holes in the third ring groove. ECK/DMW. 15th August, 1936. | ||