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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).
Report comparing cylinder finishing techniques and engine designs at competitors Austin and Daimler.

Identifier  ExFiles\Box 27\2\  Scan244
Date  2nd July 1934
  
- 2 - E.1/HP.2.7.34.

to be an improvement. The new methods had overcome a lot of complaints arising from cylinder and piston troubles.

At Austin's the cylinders came off the machine with a delightfully silky finish and this was further enhanced by a short lapping operation with a reciprocating piston before the cylinders were put into service. We were shown the special cutter used for the boring, the design of which is the subject of a patent.

At Daimler's, on the other hand the finish was not so good and nothing further was done before running, but Mr Pomeroy assured us that the results were entirely satisfactory and ring wear was found not to exceed 2 to 3 thousandths at the gap during the running in period.

The engines we saw in production at Daimler's included those for Lanchester chassis as well, but the labels are only applied as the finished product goes out of the shop.

These cylinders are integral with the crankcase and no dummy head is bolted on during boring. This would indeed be more difficult to do on an overhead valve engine.

Pomeroy claims that they have already very considerably extended the mileage between decarbonisations with the improvements to the bore and other modifications to be mentioned later.

Daimler's have only one machine, a Krause, against the six being used by Austin (one Krause and five Austin designed) and this machine at the time of our visit was engaged in machining a cylinder block of a new experimental engine in development, and not really intended for our inspection.

The most noteworthy feature of this engine is that it is not fitted with a detachable head and is intended to run 30,000 to 40,000 miles between decarbonisations which brings this period up to the point when the piston rings should be inspected, and this improvement is claimed as a result of cylinder boring and piston modification.

This engine is of the 15 HP.rating, 6 cylinders class, and according to Mr Pomeroy develops 60 HP. at 3600 r.p.m.

The cylinder is a monobloc casting with overhead vertical valves bolted to an aluminium crankcase. It is very compact and the bores are spaced in pairs to suit a four bearing balanced crankshaft.

There is no water between the nearest bores, in
  
  


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