Engine sump, fitting a magnet, Austin 7 cars

- by Ron Hayhurst

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A mod. made by some Seven owners involves fitting a magnet in the sump in order to take any wear from the moving parts literally “out of circulation”. It has been on my “to do” list for some time and an opportunity arose last month during the re-build of a spare engine.

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Some folks manage to fix it to the sump plug or make the plug itself magnetic. I couldn’t quite see where room was available for the chosen magnet as it would be very near to the inlet to the oil pump.

So looking elsewhere, as the picture shows, I settled on one of the fastenings holding the gauze. Some time ago I had acquired a selection of small magnets and was now pleased to find that one of them had a threaded hole in it. A few checks from my stock of bolts showed it to be 0BA which just happens to approximate to a ¼" outside diameter. Serendipity ! !

A stud was then made from a long bolt, such as secures the nose piece on an A7 engine, and which is threaded over only half its length. The head was sawn off to allow a 0BA thread to be put on the stud.

Having secured the stud in the crankcase with a ¼" Whitworth lock nut, a 0BA lock nut was run up the stud and the magnet temporarily affixed as shown.

The red paint was then stripped and the magnet screwed in place using Loctite Studlock.

A couple of comments:

  • • The eagle eyed will have noticed that the ¼" nut has the flats you would expect on the next size up. Could it be that this is a pre-war nut ? ? Others may have said the same of me.
  • • Not sure what these magnets are made of. I would have used a smaller one but it had no tapped hole. When I attempted to drill it, it shattered.

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