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).
Table of piston specifications, including dimensions, materials, and remarks.
| Identifier | ExFiles\Box 124\2\ scan0212 | |
| Date | 13th July 1940 guessed | |
| -2- Piece No. | Maker. | Bore. | Weight. | Skirt Dimensions. Bedding. Relieved | Top Land Dimensions. | Gudgeon Centre to Piston top. | Height of raised crown. | Volume of raised crown. | Material Spec'n. No. | Remarks. | Old Pistons (normal c/r) | R.C. Pistons new c/r --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- P.451 | Perolite | 3.5" | | AA{D. Abbot-Anderson} 3.4955" BB 3.500" / AA{D. Abbot-Anderson} BB) No.14 | 3.482" x .220" | 2.240" | .33" | 1.782 cu" 29.1 cu.cms. | A/P 404 | A number of these pistons have been fitted to Prod. Wraith & Bentley II | (Bentley (5.5/1) (Wraith (6/1) | 7.8/1 7.23/1 P.452 | Aerolite | 3.5" | 19.9ozs. | AA{D. Abbot-Anderson} 3.4955" BB 3.500" / AA{D. Abbot-Anderson} )cam grinding BB | 3.482" x .220" | 2.240" | .2" | 1.08 cu" 17.7 cu.cms. | A/P 404 | Chiefly on Wraiths used on the Continent | (Bentley (6.5/1) (Wraith (6/1) | 7.1/1 6.7/1 P.481 | Aerolite | 3.5" | 19.2ozs. | | | 2.270" | Flat top .030 down | | | Delected scraper ring. | | P.482 | ditto | 3.5" | 19.6ozs. | | | 2.30" | flush top | | | For B.60 and B.80. | | P.486 | Aerolite Split-skirt. | 3.25" | | AA{D. Abbot-Anderson} 3.235" BB 3.25 / AA{D. Abbot-Anderson} 3.235" BB 3.245" | 3.233"x 2.6" | 2.3" | flush top | | RR.53 Heat treated tin coated | Crown thickness .210" | | P.487 | Aerolite | 3.5" | 19.6ozs. | AA{D. Abbot-Anderson} 3.4955" BB 3.500" / AA{D. Abbot-Anderson} BB | X.28" | 2.3" | flush top | | ditto | Crown thickness .227" | | P.485 | Aerolite | 75 mm. 2.9527" | | AA{D. Abbot-Anderson} 2.9499" BB 2.9509" | | 2.3" | flush top | | 122 alloy heat treat tin coated | Crown thickness .187". | | RE.784 | Aerolite | 75mm. split skirt 2.9527 | | | | 2.3" | flush top | | A/P.404 | Produced by Aerolite to R.R.grinding on two dia. crown thickness .2". | | RE.785 | Aerolite | 3.25" split skirt | | | | 2.3" | flush top | | A/P.404 | R.R.grinding on two dia. crown thickness .22. | | RE.786 | ditto | 3.5" | | | | 2.3" | flush top | | A/P.404 | R.R. grinding. crown thickness .24" | | | ||