SEIZED BEARINGS.

Hawera Star, Volume XLVII, 12 May 1928, Page 15

SEIZED BEARINGS.

• COTTON WASTE. PRESENT. j A DANGEROUS PRACTICE. A technical director of a British firm writes to The A lot or in regard to a tase c.f engine failure (a seized bearing) attributed by another correspondent, reporting the episode, to faulty lubiication. He says:— “The main bearing seizure was evidently caused bv inadequate lubrication due to choking of some part of the oil circulation system. “It is stated that the filter was clogged with slime and a substance resembling cotton waste. Slime alone is often nothing more dangerous than j oil slightly thickened by soot, due to I an over-rich mixture, and it is surpri.s-1 ing how little harm results from its

presence if nothing abrasive be included, but cotton waste is of more siguilieance, lor it makes an excellent base on which every other kind of solid, such as carbon deposit, soot, and dust, can build up and choke a gauze strainer or an oil duct, with dire results. “In more than one instance we have discovered cotton waste in engine deposits in circumstances wehe its presence could not be explained hv those concerned, but there is no doubt a tout the analytical result, for after sepai a • Lion of the oil, carbon and metal d .si, it is possible to detect twists of mn.ticoloured fibre under the microscope. Tests have shown that, when the mirFare of an iron or aluminium casting is wiped over with cotton waste, an appreciable amount of cotton sticks firmly to it and cannot be easily rinsed oil'. When the surface is inside the engine, however, the fibres are gradually carried into circulation with the oil.

“Whether the deposit in Air. Job’s car was in fact built upon a basis of

cotton waste, was introduced in the l manner suggested or via ‘oil ex cask’ | (which can never be warranted lree from muck) is a question which the I av ailable data do not enable us to ans- ! wer, but general experience points to j the cotton waste theory as affording | a better explanation than any chemical ! action between different kinds of oil. I To the best of our knowledge, and wo j make it our business to be acquainted j with all oils in general use, there is ! not a motor oil on the market, except I racing grades, which consists of vegei table oil.

“The jelly-forming substances referred to in Mr. Job’s letter is castor 1 oil. and only the spectial racing oils (recognizable by the strong castor oil I smell from the exhaust) contain any | appreciable amount of it. Whilst it is j obviously the best plan to keep to * lie I grade of oil, the theory that two oils, | separately satisfactory, will together | cause 'disaster is in our opinion very j much over-worked, and often merely • obscures the real truth.”