Rolls-Royce Archives
         « Prev  Box Series  Next »        

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).
Modifications for Vandervell main bearings on Wraith III and Bentley III models.

Identifier  ExFiles\Box 115\3\  scan0290
Date  3rd October 1938
  
1020
File
DA.{Bernard Day - Chassis Design}7/G.3.10.38.

WRAITH III and BENTLEY III. VANDERVELL MAIN BEARINGS.

Please receive herewith :-

E.CD.924 Vandervell Main Bearings with Increased Crankshaft Oil Retaining Thread - Wraith III and BENTLEY III.

In accordance with Rm{William Robotham - Chief Engineer}/Swdl.{Len H. Swindell}7/MH.{M. Huckerby}16.9.38. we have reduced the length of the crankshaft rear journal by .125" and added this amount to the oil retaining thread at rear end. The rear end cover nose is lengthened to suit, and the bearing cap studs in the crankcase are moved forward by .0625".

The diametral location of the rear bearing thrust washers results in a rather massive rear bearing cap.

It should be noted that the end float of the crankshaft should be within the limits of .002" to .004", this demands accurate machining of faces for thrust washers, and owing to the expected variation of the thrust washers it may be necessary to adopt selective assembly to obtain the stated end float or even a range of thickness of thrust washers.

For the time being the remaining particulars for the fitting of Vandervell bearings should be taken from the Vandervell drawing L.1076, a print of which is available in the Engine Design Section. This refers also to the other six journal bearings.

If the Vandervell bearings are later considered for standardisation, a final design embodying improvements and simplification will be made after discussion with the makers of Vandervell bearings.

It is hoped that due to the improved oil retaining thread shown on this design, that the oil groove and drain holes in the rear half of the rear bearing may be deleted, this will be tried in the course of the experiment.

The crankcase boring for these bearings should be particularly noticed viz. 2.6635" + .0005".

For the experiment, the standard forgings for all the bearing caps with the exception of the rear one should be suite for producing the new caps, a modified forging is required for the rear cap.
  
  


Copyright Sustain 2025, All Rights Reserved.    whatever is rightly done, however humble, is noble
An unhandled error has occurred. Reload 🗙