talve Guides Back to Size
Page 57
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▪ QUIPMENT which provides a means of bringing back to —• standard size the bores of worn valve guides without removTig them from the cylinder head is now being marketed in the J.K. through James Sewell and Co. Ltd. Already widely used America, it will be sold in Britain with the trade name The main part of the equipment, which is sold as a kit, is a 3°1 that performs a knurling operation on the inside of the uide bore. This is a ground rod with a small cutting wheel, set, rid free to rotate, in a longitudinal groove in its circumference. 'he cutter is at a slight angle so that when the tool is rotated n the guide bore it feeds down without force being needed, .aving a thread-like indent in the surface. Various diameters f the tool are made to suit all sizes of valve guide fitted to iritish engines, although the cutting wheels are the same for all. :hree sizes are made, those providing for guides worn up to -010 in., 0-020 in. or 0-030 in.
All three sizes are supplied in the kit, which also includes a earner for use after the knurling operation to clean up the ore to standard size, a special drill and jig to make a small ut-out in the end of the guides and give a start to the knurling utter, a hexagon driving bar for the knurling tool and reamer rid a handpiece with which the job can be done by hand. The quipment is designed, however, to be used with a hand drill rid in this case a speed reducer with a ratio of 5. to I or more zill be needed; this is not supplied in the kit.
Demonstrations witnessed by Tire Commercial Motor showed that an excellent job was done with the Xlmees equipment. Virtually no skill was needed to restore the valve guide bores to the standard size and very little time was taken. In one way, the bore surface left after using the tool is an improvement on the
standard finish; the indent in the bore provides a path for lubricant. This helps to keep the valve cooler and reduces the chance of carbon formation and valve sticking.
Concessionnaires: James Sewell and Co. Ltd., 45 Cromwell Road, London, S.W.7.
Price: £19 19s. (retail).