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).
Causes of exhaust manifold failures and proposed solutions.
Identifier | ExFiles\Box 6\7\ 07-page107 | |
Date | 26th February 1931 | |
X8230. SG.{Arthur F. Sidgreaves - MD} FROM E.{Mr Elliott - Chief Engineer} C. to R.{Sir Henry Royce} WOR.{Arthur Wormald - General Works Manager} C. C. to BY.{R.W. Bailey - Chief Engineer} HS.{Lord Ernest Hives - Chair} PN.{Mr Northey} 31/M.26.2.31. /1330 /7240 EXHAUST MANIFOLDS. We agree that the question of exhaust manifolds requires serious attention. At the same time it should be recognised that the manifolds on RR. cars probably run under worse conditions than those on most other cars as regards heating owing to a number of reasons, such as: (1) High standard of silence calls for higher back pressure in the exhaust system. (2) Restricted air flow under the bonnet. Most people use louvred bonnets. (3) High temperatures under the bonnet often induced by hand operated shutters. (4) Hauling luxurious bodywork at high average speeds which can be safely maintained with our good braking demands relatively higher output. We believe all of these conditions are become much intensified since the days of the Silver Ghost. Moreover the last one or two series of Ghosts which had 4 wheel brakes were fitted with a form of exhaust manifold having much in common with those we used on P. I. and gave no trouble so far as we know. The exhaust pipe on 18.G.IV which broke was not a good casting, being below drawing size at the point of fracture. The core in fact was eccentric and the wall thickness on one side was twice the wall thickness on the other. Nevertheless pending the production of a new design alterations for locally stiffening up this pipe were asked for in our memo. 34/M10.1.31. As regards what has been done to find a permanent cure these troubles we have made a start with P. I. and SY. has produced at our request 2 schemes for manifolds, one for the cars having cast iron heads and the other for the later P. I's. which had different manifolds to suit aluminium heads with ignition plugs on exhaust side. These schemes we are engaging in perfecting for submission to R.{Sir Henry Royce} and we hope to eliminate both the exhaust blow and breakages by the use of glands. As regards the 20HP. and the 20/25HP. the problem appears somewhat more difficult owing to the use of 3 exhaust ports, but we are about to ask SY. to produce a scheme of exhaust pipe which should be much stronger than, though possibly not so efficient, as the one we have. (1) | ||