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).
Specifications for Delco high and low pressure valve springs.
| Identifier | ExFiles\Box 28\1\ Scan226 | |
| Date | 4th February 1931 | |
| 1832 DELCO VALVE SPRINGS. 4.2.31. HIGH PRESSURE. | | TYPE "C" | TYPE "E" | TYPE "G" | |---|---|---|---| | FREE LENGTH. | .750 | .735 | .760 | | OUTSIDE DIA. | .404 | .437 | .438 | | INSIDE DIA. | .278. | .292 | .289 | | DIA. OF WIRE. | .063. | .073 | .075 | | NO. OF WORKING COILS. | 6 | 5 | 5 | | TOTAL NO. OF COILS. | 7 | 6 | 6 | LOW PRESSURE. | | TYPE "C" | | TYPE "G" | | |---|---|---|---|---| | | OUTER | INNER | OUTER | INNER | | FREE LENGTH. | .520 | .694 | .530 | .700 | | OUTSIDE DIA. | .444 | .234 | .439 | .233 | | INSIDE DIA. | .298 | .178 | .277 | .177 | | DIA. OF WIRE. | .073 | .028 | .081 | .028 | | NO. OF WORKING COILS. | 3 1/2 | 7 1/2 | 3 | 7 1/2 | | TOTAL NO. OF COILS. | 4 1/2 | 8 1/2 | 4 | 8 1/2 | | ||