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).
Bentley cylinder distortion and expansion tests for 3.5 litre and 4.25 litre blocks.
| Identifier | ExFiles\Box 86\1\ scan0206 | |
| Date | 2nd July 1936 | |
| x219 Hs{Lord Ernest Hives - Chair}/WB.{Mr Brazier/Mr Bell}7/KW.2.7.36. NOT SENT OUT Bentley Cylinder Distortion Tests. 3½ litre EB.1752, and 4¼ litre EB.2561 Cylinder Blocks. The cylinder blocks were supplied secured to crankcases, the bores measured, and the assembly then heated up by circulating oil at 125°C. through the coolant space in the cylinder block, the bores being then re-measured. Finally, after the blocks were released from the crankcases, the bores were again checked, to measure the distortion due to tightening down. Incidentally, the cylinder blocks supplied were not new, and the dimensions of the bores before test were not measured, therefore the expansions and distortions given on the attached charts are relative to the initial dimensions of the bores when secured to the crankcase. Also, the heads were not fitted for these tests. 3½ litre EB.1752. Expansion. The average expansion measured .0027" whilst the minimum to maximum figures recorded were .0016" to .0039"; a difference of .0023". The variation was not consistent, but if anything, there was a slight tendency to expand more at the crown (Z) and longitudinally (A). Distortion. The distortion due to tightening up on the crankcase occurred mainly at the skirt (X), the minimum to maximum figures being .003" reduction to .0025" increase in diameter, a total of .0055". | ||