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).
Technical memorandum detailing modifications to the J.1. engine components, page 2.
| Identifier | ExFiles\Box 30\2\ Scan107 | |
| Date | 9th November 1932 | |
| - 2 - E.6/HP.9.11.32. inlet valves, and sparking plug pushed in nearer to the combustion space .1". Instructions for this will be squared up this week. (7) Cylinder Block. There is a special cylinder block for J.1. This has the circular water covers which leave sufficient support in the casting for giving maximum support to the joint face of the head. This cylinder block should be modified to have the cross passage removed, which served to carry the heatxxxxxxxx from the exhaust to the inlet jacket, and which is no longer required. (8) Valve Rocker Gear. On the present J.1. valve rocker shaft is in two sections. This will be altered to be all in one section. The head is in cast iron and will then be the same as the 20/25, except that the rockers are slightly respaced as regards the centres. (9) Camshafts. The first J.1. engines will be fitted with standard camshafts, with which 107 HP. has been obtained at 3750 r.p.m. but these shafts will require the addition of an eccentric for driving the petrol pump. Special cam forms with short toes - LeC.3262 have been issued for the camshafts that it is intended eventually to standardize. (10) Magneto. This will not be required. (11) Distributor Head for Battery Ignition. - The normal direction of rotation for the distributor is in the reverse direction to the J.3. type of ignition that we should like to use on J.1. We shall, therefore, go further into this question to see if J.1. cannot be reversed. It means that new oil pumps will be required - that is to say -those used on the tank installation will no longer be suitable, and the oil pipe lines will require altering. The present standard distributor would not be satisfactory for the speed at which J.1. is to run, and it is necessary to have an improved ignition on the lines of Peregrine. This matter can be settled up this week. | ||