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).
Remedies for clutch slipping and observations on exhaust system component performance and failures.
| Identifier | ExFiles\Box 71\4\ scan0105 | |
| Date | 31th March 1925 guessed | |
| - 3 - Several cases of clutch slipping could not be remedied by fitting stronger springs - probably due to the clutch trunnion sleeve being too tight on its shaft, and so becoming almost solid with this when hot. We have had no further slipping after making sure everything was working perfectly freely. Clutch spring operating levers (spring end) require clearing away slightly, to ensure that they bed correctly on contact pieces. Clutch brake satisfactory. We find the best position for this is obtained with .035" clearance between halo disc and the clutch brake flange. Clutch jaggers were very bad at commencement of tests - we have been able to eliminate these to a very considerable extent by making sure that the central clutch plate floats freely in its bearings. Hard marks on these bearing shafts appeared to indicate that the plate was running out of truth. When these hard marks were eased off, clutch jaggering became decidedly less marked. Clutch case requires altering so that clutch springs can be taken out without having to dismantle the clutch casing. Dismantling of clutch casing would be simplified considerably if the studs, as at present fitted, were replaced by bolts. Clutch trunnion requires oiling every 2,000 miles (1/2 syringe full of oil). Universal coupling joint inside clutch appears to be O.K. if lubricated every 2,000 miles with 1/2 syringe full of oil. We previously lubricated this every 1,000 miles, and on dismantling found that it could do with less. We have had no trouble with this since cutting down the lubrication. No oil from this joint leaks on to clutch friction faces. They were found quite dry, and in good condition, on the occasions when the clutch was dismantled. EXHAUST SYSTEM. Quite good as regards silence and exhaust booms. Cut-out valve return springs require encasing. In very wet weather these become choked up with dirt, and will not return valve immediately the cut-out is operated. Exhaust gases burn leather covers on N.S. rear foot brake adjustment, when cut-out is open. Fish-tail insufficiently strong - opens out badly. The two sliding joints, to accomodate expansion of parts, work well, and there are no exhaust blows from them. (These joints are fitted with stainless steel sleeves). Exhaust throttle insufficiently solid - distorts very badly, causing throttle to stick badly. Asbestos lagging on front silencer requires two more retaining bands. This lagging very soon failed. Asbestos lagging round down pipes is fatal to these parts. Pipes scale very badly under the lagging, and burn right through. Exhaust manifolds are very difficult to dismantle after any running. The manifolds should not be dowelled so definitely on to the cylinder block. At present the rear dowel hole is slotted to accomodate expansion. The front hole also should be slotted - these are always very tight on dowel pins when dismantling is necessary. Rear exhaust manifold cracked between two ports after 9,600 miles | ||