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).
Treatments for cylinder blocks and radiators to prevent corrosion and improve performance.
| Identifier | ExFiles\Box 27a\3\ Scan075 | |
| Date | 2nd November 1929 guessed | |
| -2- Such a treatment given to cylinder blocks would be an advantage rather than otherwise, from several standpoints; for instance, it would tend to remove casting stresses without materially affecting the hardness of the nickel iron now used. Other methods of protection such as zinc coating, linseed oil treatment, coslettising, etc., or the introduction of a zinc element into the water system are not nearly as practicable or efficient. The soft water now being used for filling radiators should eliminate the lime and magnesia from the sludge and from the deposit on the tubes. Further, the detrimental effect of the zinc chloride which remained in the radiator in spite of washing after the soldering operations, should now be practically eliminated by the additional cleansing with ammonium chloride solution which is now standardised. With respect to the addition of 0.10 % sodium phosphate to the water. This has a very marked effect in reducing the accumulation of corrosion sludge even when used in conjunction with cylinder blocks which have not been given the above-mentioned oxidising treatment. It might not be found necessary with the oxidised cylinder lining. On the other hand some advantage should be gained by sending out cars with the sodium phosphate addition, but it must be borne in mind that to get continued advantage more phosphate should be added from time to time, and when re-filling. Our laboratory tests show that the "RR50L" alloy now being used for cylinder heads is superior, from the corrosion standpoint, to the 8%copper aluminium alloy used in the past. Its substitution, therefore, will undoubtedly reduce the amount of aluminium hydroxide formed. This product is of a gelatinous nature. With respect to the radiator tubes themselves. These have shown considerable corrosion and dezincification in the past, with resultant breakdown and accumulation of corrosion products. The 28% zinc content of the brass of the tubes makes them susceptible to this trouble. The use of copper tubes such as employed by R.R. of America, or even the considerable reduction of the zinc content of the tubes would eliminate this particular trouble. Increased conductivity of the tube material would result, pure copper, for instance, having about three times the conductivity of 72:28 brass. Copper tubes can be obtained of equal stiffness to that of our present tubes. The present method of clearing out choked radiators appears to be difficult to improve on, though a subsequent treatment with 0.5% phosphoric acid cleans up the radiator tubes themselves if the caustic soda solution has not been quite enough. HS.{Lord Ernest Hives - Chair} HC | ||