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).
Side and end sectional views and specifications for the 'C. F. R.' Engine and its carburetor.
| Identifier | ExFiles\Box 27a\4\ Scan071 | |
| Date | 1st November 1931 | |
| NOVEMBER, 1931 A Gulf Publishing Company Publication 115 FIGURE. 4 Side and End Sectional Views of “C. F.{Mr Friese} R.{Sir Henry Royce}” Engine cylinder barrel and on the collar which is threaded to it are six per inch. Figure 4 shows as well (at the left of the end section near the top) the micrometer which, with the aid of a calibration chart, serves to give the compression ratio at which the engine is set at any time. At the top of the end section in Figure 4 may be seen the truss mechanism which supports the rocker-arm shaft and compensates for the raising and lowering of the cylinder by 'inging the rocker-arm shaft automatically to the proper elevation to maintain the adjustment on the valve lash without the necessity of changing push-rod length. Essential dimensions of the engine as now built are as follows: Bore, in. . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 1/4 Stroke, in. . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 1/2 Cylinder displacement, cu. in. . . . . . . . . . . . . . 37.4 Intake-valve diameter, in. . . . . . . . . . . . . . . 1 3/16 Exhaust-valve diameter, in. . . . . . . . . . . . . . 1 3/32 Connecting-rod bearing diameter, in.. . . . . . . 2 1/4 Connecting-rod bearing length, in.. . . . . . . . . . 1 5/8 Front main-bearing diameter, in.. . . . . . . . . . 2 1/4 Front main-bearing length, in.. . . . . . . . . . . . . 2 Rear main-bearing diameter, in.. . . . . . . . . . . 2 1/4 Rear main-bearing length, in.. . . . . . . . . . . . . 4 3/4 Piston-pin diameter, in.. . . . . . . . . . . . . . . . . 1 1/4 Connecting-rod length, in.. . . . . . . . . . . . . . . . 10 Number of piston rings. . . . . . . . . . . . . . . . . 5 Timing-gear face-width, in.. . . . . . . . . . . . . . . 1 Carburetor flange . . . . . . . . . . . . . . . . . S.A.E. Carburetor-flange diameter, in.. . . . . . . . . . . . 1 Exhaust manifold pipe-tap size, in.. . . . . . . 1 1/4 Spark-plug size, mm.. . . . . . . . . . . . . . . . . . . 18 Indicator-opening diameter, in.. . . . . . . . . . . . . 7/8 Indicator-opening threads per inch. . . . . . . . . 18 Approximate weight, lb.. . . . . . . . . . . . . . . . . . 450 THE CARBURETOR Essential features of the carburetor are: manifold diameter 15/16 in., diameter venturi throat 1/2 in.; a single jet taking fuel from either one of two or from any one of four float bowls, the change from one fuel to another necessitating only the opening of one valve and the closing of another; mixture ratio regulated not by changing jet size, nor by adjusting a needle valve, but by regulating the amount of air bled through an auxiliary air bleed or inlet which enshrouds the tip of the fuel jet; down-draft intake with fuel jet as close as possible to the inlet port to give minimum length of fuel travel; operation without any applied heat; sight glasses on float bowls for visible indication of fuel level; a fuel reservoir connected to the inlet of each float bowl; means for conveniently and completely draining float bowls and fuel reservoirs when changing fuels; fuel passages well protected against the entrance of dirt; muffler on the main air inlet. The “C. F.{Mr Friese} R.{Sir Henry Royce}” carburetor is described in detail in the Journal of the Society of Automotive Engineers, November 1931. It is illustrated by the photograph, 1 | ||