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).
Technical comparison of silent tappet specifications for various engines.

Identifier  ExFiles\Box 17\6\  Scan169
Date  29th November 1933
  
FILES:
X7060
SILENT TAPPET COMPARISONS:

Spring Load Only (Cadillac & Pierce Arrow, spring load taken at the same figure as J.III)

Eccentric Eccentric Pierce Arrow Phantom
Cadillac .47: 1 J.III .267: 1 Direct Acting. Direct Acting
Dia. Of Plunger. .6234 .5245 .4995 ø .4995
Clearance between Plunger and Case. .0016 .00075 .002 .0005
Clearance Area A.{Mr Adams} sq.in. .00313 .00120 .00314 .00079
Effective length of Plunger. .932 .650 .750 .545
Max. load on Plunger (lbs.) 58.8 33.45 125 149
Max. Press of oil beneath plunger (P.lbs/sq.in) 192.8 155 637 760
(Max) Leakage Factor PA{Mr Paterson}/L. .647 .286 2.67 1.103
Lift of Ball Valve. .015 .005

ø Plunger return spring : Free length = .95 - Load = 0
Fully compressed = .527 - " - 7 lbs.

Taper Spring (Rectangular Section Wire. Inner Dia. (Small .467
(Depth .080 Thickness .040 (Large .600 Total 5 coils
  
  


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