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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).
The performance and wear of a cast iron crankshaft and associated bearings after service in a petrol engine.

Identifier  ExFiles\Box 132\1\  scan0021
Date  18th April 1927 guessed
  
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immeasurable, not exceeding 0.00025". The white metal bearings were also in excellent condition.

This particular test is of partial value only because the crankshaft is subjected to bending load only, and does not reproduce the exact conditions which are obtained in an engine under the normal working conditions.
The results are, however, comparative, and show that cast iron crankshafts compare very favourably with steel shafts under these particular circumstances of the test.

RESULT IN SERVICE.

A cast iron crankshaft of the same composition as the material used in the previous tests was fitted into a four-cylinder petrol engine, and placed in ordinary goods transport service March 25th, 1935, and continued to run up to October, 1937, when the engine was dissembled for internal examination.

The following observations were made:-

Main bearings.

Bronze shells with white metal linings.

Big End Bearings.

R.R.56 shells in top and bottom halves.

Crankshaft Main Journals.

Nominal size 2.750".

No. 1. No. 2. No. 3. No. 4. No. 5.
Axis A.A. -.0025 -.00325 -.003 -.003 -.0025
" B.B. -.0022 -.003 -.0025 -.0035 -.0025

Crankshaft Journals.

Nominal Size 2.375".

No. 1. No. 2. No. 3. No. 4.
Axis A.A. -.0005 -.0005 -.00075 -.0005
Axis B.B. -.0005 -.0005 -.00075 -.0005

Considering the original tolerances allowed on main and journal diameters, the approximate amount of wear on the main bearings is between .001 and .002, and the
  
  


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