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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).
Letter to Studebaker Corporation with technical questions about exhaust valves, dampers, and gearboxes.

Identifier  ExFiles\Box 174\2\  img289
Date  1st December 1938
  
S. Sparrow, Esq.,
Studebaker Corporation,
South Bend,
INDIANA. U.S.A.

Dear Sparrow,

Do you accept the statement that for a given M.E.P. the exhaust side valve will run hotter than the corresponding overhead valve ?

In our experience, hot exhaust valves make their presence felt by the engine continuing to run after switching off. This can be completely cured by using sodium-cooled exhaust valves on a 118" power engine, but we wonder if you know of a simpler means of achieving our objective other than by the accepted way of bringing the valve guide as far up the stem as possible.

Have you found the shape of the exhaust valve head produces any particular result with regard to reducing the scrubbing action of the gas? Is the valve temperature sensitive to port shape ? Do you find that hydraulic lash adjusters reduce the valve temperature ?

We are running the crankshaft vibration damper which Grylls brought back from the States, and wonder if you have found this to be perfectly satisfactory under service conditions. The rubber driving cone seems to us to be somewhat small in dimensions.

With regard to your overdrive gearbox with the electrically-operated direct gear, do you make any provision to prevent unintelligent owners engaging direct when they are running at speeds on the overdrive which make this procedure to be highly undesirable ?
  
  


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