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).
Use of bronze versus black leaded steel nuts on exhaust manifolds to prevent seizing.
| Identifier | ExFiles\Box 66\2\ scan0278 | |
| Date | 20th June 1927 | |
| X830 C.Hs.{Lord Ernest Hives - Chair} BY3/H.{Arthur M. Hanbury - Head Complaints} 20.6.27. NUTS SECURING EXHAUST MANIFOLDS. ------------------------------ Some long time ago you raised an issue, which was on the Phantom chassis at that time, in connection with the use of bronze nuts on the exhaust system, having in view, as its object, the prevention of seizing between the nuts and the studs securing the manifolds. We supplied you with a number of nuts, with which you expressed yourself as being satisfied, but they left a doubt in your mind in regard to whether they would remain tight in service owing to the bronze nut expanding more than the steel stud on to which it fitted. In view of this, therefore, the matter was left over, as you proposed to use these nuts on a number of chassis and then make a definite decision for or against. I am reverting to the above matter because one customer with a 20 HP. chassis has complained that he could not take down his exhaust manifold from the engine owing to the nuts having seized. We are supplying this customer with bronze nuts, but we would like to know whether we should generally adopt the bronze nut or not. There is one other aspect of the case which could be exploited, and I would like to know whether anything has been done, namely, the use of slack steel nuts, not tightened up very much, and well doped with black lead before fitting, during the dynamometer running, as one feels that 99% of the trouble is done on the dynamometer, and that if the final nuts were not fitted until after the dynamometer run, and the studs were then well black leaded before fitting the nut, the danger would disappear and the danger of the slack nut would also not be a nightmare for the future. BY.{R.W. Bailey - Chief Engineer} By | ||