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).
Comparison table of silent tappet systems for Cadillac, J.III, and Phantom II engines, considering only spring loads.
| Identifier | ExFiles\Box 106\5\ scan0102 | |
| Date | 14th September 1933 guessed | |
| COMPARISON OF SILENT TAPPET SYSTEMS SPRING LOADS ONLY CONSIDERED. (NOTE: CADILLAC SPRING LOAD TAKEN SAME AS J.S.) | | CADILLAC. (ECCENTRIC RATIO .47:1) | J.III. (ECCENTRIC RATIO .267:1) | PHANTOM II DIRECT ACTING SCHEME. | |---|---|---|---| | DIA. OF PLUNGER. | 0.6234" | 0.5245" | 0.4995" | | CLEARANCE BETWEEN PLUNGER & CASING. | 0.0016" | 0.00075" / 0.0010 | 0.0005" / 0.0010 | | CROSS SECTIONAL -A CLEARANCE. AREA SQ. INS. | 0.00313 | 0.00120 | 0.00079 | | EFFECTIVE LENGTH OF PLUNGER -L | 0.932" | 0.650" | 0.545" | | MAX. LOAD ON PLUNGER. LBS. | 58.8 | 33.45 | 149.0 | | MAX. PRESSURE OF OIL BENEATH PLUNGER - P - LBS/SQ. IN. | 192.8 | 155.0 | 760.0 | | (MAX.) LEAKAGE FACTOR - PA{Mr Paterson}/L | 0.647 | 0.286 / 0.61 | 1.103 / 3.53 | Pencil figures - assume that we work to the same manufacturing limits as Cadillacs instead of to an impractical clearance. | ||