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 report discussing issues with shackle play causing knocks and adjustments to the carburation to improve low-speed power.
| Identifier | ExFiles\Box 46\2\ Scan113 | |
| Date | 4th April 1922 guessed | |
| contd:- -3- the side play in the shackles had increased and caused serious knocks on rough roads (we have these to perfection) but I now find that it was the upper pin of the rear shackles on the front spring that needed attention; this is not the part that would wear most: the bottom pin and faces have 3 or 4 times the motion and less chance of retaining their oil so that this upper joint must have had slack when it was fitted up. The idea is therefore not to delay the cars for serious alterations but make a good fit of all the shackle joints especially for end play. It is also possible to caseharden many of the parts which are left soft at present i.e. the link faces and the frame fitting. Also it has occurred to me that many of the joints can be more or less boxed in or covered to prevent the road water and grit getting to them at least as freely as at present. CARBURATION. There have recently come to my notice remarks about want of power at slow speed, and defective carburation. I have already sent the advice of a larger low speed Venturi (choke); the exact size of this should be found on the test plate because in the past it has been too small, and therefore the extra air has demanded too large an opening, and hence to get the mixture strong enough for the high speed it has been too strong for low speed (500) and full throttle. We are going on increasing the throat until we find it too large - at present we are using .7 which we have made by filing. Now naturally if we can use a larger throat we can get more power and better consumption. We are now testing this on the road. contd:- | ||