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Slow running tests for a Bentley engine, comparing different non-standard parts.


Identifier  ExFiles\Box 83\1\  scan0260
Date  23th October 1936
  
200d

To Rm. {William Robotham - Chief Engineer}

Rm {William Robotham - Chief Engineer} /FD. {Frank Dodd - Bodies} 16/JH. 23.10.36.

Bentley Slow Running.

The slow running of 6-B-IV after the completion of 17,000 miles was excellent, a marked improvement on the present standard car.

The engine of 6-B-IV had the following non-standard parts :-

(1) Deterbulated cylinder head.
(2) Small induction pipe) } 3 1/4 Litre Type.
(3) Small carburetters }
(4) Delco Remy Ignition.

We have carried out a series of change-over tests between 6-B-IV and 5-B-IV, the latter car being known to be a very erratic slow runner.

1st Test.

Deterbulated head and small carburetters with small dia. induction pipe fitted to 5-B-IV.

Result :-

Excellent slow running at 6 M.P.H. under load and with an even tick over in nutral.

2nd Test.

Deterbulated head with large carburetters and large dia. induction pipe.

Result :-

Slow running good at 7 M.P.H. but just lacking in smoothness when running light in nutral.

Remarks :-

We would say that the deterbulated cylinder head is worth 80% and the small carburetters fitted to this head 20% for aiding slow running.
  
  
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).


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