Rolls-Royce Archives
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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).
Engine tests investigating pre-ignition, temperature changes, and the effects of varying oil pressure.

Identifier  ExFiles\Box 71\2\  scan0171
Date  18th October 1926 guessed
  
contd :-
-4-
drop in power. The pre-ignition was not as severe as we have
experienced and gave no popping back in the carburetter.
With pre-ignition the top of the liner temperature
rapidly increased to 132.8oC where it remained constant, the
aluminium cyl. temperature at the same spot was 106oC. Pre-
ignition did not seem to appreciably alter the temperature of
the lower parts of the bore.
During some of these tests it was thought that a
slight variation of the cyl. skirt temperature was observed when
the oil pressure was varied. Consequently a test was made
where in which the oil pressure was reduced and although the
actual oil flow through the bearings was not measured at the
time, we estimated from previous figures taken on this engine
that the flow was reduced by roughly 70%. The normal oil flow
on this engine is considerably higher than on the average engine
due to the worn state of the bearings after a large member of
hours this particular crankcase unit has run on the test bench.
At 2000 r.p.m. the skirt part of the liner was
approximately 10oC higher with this reduced flow. The tempera-
ture of oil admitted to the bearings was kept constant at 60oC
in each case by a cooler. The higher parts of the liner were
not affected to any appreciable extent.
As the exact flow of oil was not known but only
estimated we intend to repeat this at the first opportunity to see
if the temperature is likely to increase much with well fitting
bearings.
contd :-
  
  


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