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, considering spring loads only.
| Identifier | ExFiles\Box 17\6\ Scan156 | |
| Date | 25th September 1933 guessed | |
| COMPARISON OF SILENT TAPPET SYSTEMS SPRING LOADS ONLY CONSIDERED. (NOTE: CADILLAC SPRING LOAD TAKEN SAME AS J.3.) CADILLAC (ECCENTRIC RATIO 1.47:1) J.IIIX. (ECCENTRIC RATIO 1.267:1) PHANTOM II DIRECT ACTING SCHEME. DIA. OF PLUNGER. | 0.6234" | 0.5245" | 0.4995" CLEARANCE BETWEEN PLUNGER & CASING. | 0.0016" | 0.00075" (0.0016) | 0.0005" (0.0016) 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. | ||