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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).
Proposed change to the Condor engine valve lift curve and cam timing.

Identifier  ExFiles\Box 33\4\  Scan087
Date  10th September 1927
  
BY.{R.W. Bailey - Chief Engineer} from E.{Mr Elliott - Chief Engineer}
c. to BJ. RG.{Mr Rowledge} Hs.{Lord Ernest Hives - Chair}

Kimo

El/M10.9.27.

X.3616
X.1770

PROPOSED CONDOR VALVE LIFT CURVE.

In reply to your memo. BY12/G7.9.27, we cannot see that a difference of 2 or 3 thousandths of an inch between the lifts of the exhaust and the inlet valves is of any importance hence there appears to be no objection to going on with a common exhaust and inlet cam of .350 lift.

Regarding the timing we have not made any alteration to the length of the cams over the heavy acceleration, both DES.682 and Lec.2455 having 60 divisions duration with respect thereto.

The proposal however is to alter the angle between the cams from 112° to 110° which has the following effect on the timing ga diagrams -

HEAVY ACCELERATIONS ONLY.

Fig.1.
IN 10 6 EX
50 54
Angle between cams 112°. Present camshaft.

Fig.2.
IN 10 10 EX
50 50
Angle between cams 110°. Proposed camshaft.

It is considered that the inlet closes late enough but that the tendency at the present time is to close the exhaust a little later, which enables us to use the figures shewn in fig. (2).

The only reliable way in which to judge one timing against another appears to be by comparing the periods of the heavy acceleration, and Mr. Royce would like this to be taken as the standard in future.

Regarding the RR.F. timing there seems to be a considerable difference between the diagram given on Sch. 888., and the timing shewn in report Hs{Lord Ernest Hives - Chair}/VHl/LG10.8.27.

contd :-
  
  


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