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 design, manufacturing, and assembly of Cadillac hydraulic lash adjusters.
| Identifier | ExFiles\Box 125\1\ scan0121 | |
| Date | 29th October 1934 guessed | |
| COPY X1729 CADILLAC HYDRAULIC LASH ADJUSTERS. The following notes apply to parts of the Cadillac hydraulic lash adjusters and are intended to be of assistance in design, manufacturing, and assembly. It is to be noted that changes have been introduced into several of the parts to reduce the cost of manufacturing as compared with previously used parts, but thorough tests have shown no reduction in efficiency of operation. All parts changed carry an "X" preceding the blueprint number. B.P. #X885310 Cylinder-Hydraulic Lash Adjuster. Tolerance on hole diameter has been increased from .0002" to .0004" for one size. Each hole is checked for size with plug gages. Cylinder size is by number, which is stamped in casting near hole. Assembly of plunger and cylinder is done by matching numbers. Allowable clearance limits are from .0012" to .0020". The only manufacturing difficulty with this part has been that of obtaining a round, straight, smooth hole at the lower part of the plunger travel. A "blind" hole is used because of the difficulty of sealing a thru hole after finishing, without distortion of the cylinder. Hydraulic pressure in the cylinder varies from 0 to 135 #/in.2. B.P. #883207 Assembly-Hydraulic Lash Adjuster Plunger. Tolerance on plunger assembly diameter has been increased from .0002" to .0004" for one size. Sizes are selected and numbered, and assembly in cylinders is entirely by matching numbers. Each plunger assembly is tested for leakage rate, as it is nearly impossible to obtain leakproof valves, but it is highly desirable to reduce the leakage rate to the absolute minimum as determined by manufacturing costs. Successful operation of the lash adjuster is obtained only if and when the leakage rate past the plunger valve is very low. The manufacturing troubles with this assembly and its component parts have been as follow :- 1. Failure to maintain concentricity of diameters as specified. This leads to sticky valves and sluggish action. 2. Distortion of the plunger #882927 by assembly of the cap #881229. This requires grinding of the assembly as a unit to maintain the diameter limits specified over the length of the plunger body. | ||