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).
List of modifications for a carburettor system, detailing changes to the venture, piston, jet, and diffuser.
| Identifier | ExFiles\Box 179\3\ img087 | |
| Date | 11th December 1912 | |
| -6- (3) Modification led.2977 which increases the distance between the small venture and the throttle edge in an open position to be made as one unit with the throttle body (E.82773). (4) Incorporation of draining of surplus petrol and resulting through small venture. (5) Original suction passages from, the small venture to the original suction chamber to be deleted. (6) Provision of air restoration vent from main intake to float chamber. (7) Increased clearance between float chamber wall and the float as the latter lifts to close the needle valve. * (8) Suction piston to be 18 ozs. in weight and have 45o seating. One hole in side of piston .025 dia. Four holes .062 dia drilled through into the piston at right angles to the seat. The 45o seating to be cut in carburetter casting instead of using a separate piece. Similar scheme is shown on V.1324/8. The layout of steel centre guide is to led.2997. (9) Main jet orifice to be .150 diameter instead of .125 dia. (10) Diffuser. (a) Delivery holes in diffuser head to be inclined as in (E.58570)., 4 in number and .125 diameter. (b) Diffuser bore to be .200 diameter. (c) Top row bleed holes to be .100 higher than shown on (E.58570), 6 in number and .055 dia. (d) Bottom row of bleed holes to be in original position 6 in number and .039 diameter. (e) Air supply holes in diffuser guard tube (E.92636) increased to .125 diameter. (c) & (d) in this section may further have alterations. | ||