Clutch thrust bearing - inspection cover BH18

- by Ian Moorcraft

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Regular oiling of the clutch thrust race is often neglected. It’s easy to think there is enough oil mist in the bell housing to make it unnecessary, but I have seen some spectacular failures of the thrust bearing disintegrating due to running dry, along with most of the rest of the carrier.

If you have a car with a bacon slicer starter removing the inspection cover can be quite difficult. Although the cover BH18 has always been drawn in the parts list with two holes, nearly all you come across will have these slotted as supplied new.

If you slacken the two cheese head screws and try to slide the plate up to remove it you will find it hits the bacon slicer case. You need to slacken them to being almost out to get enough clearance. Now this is the danger, if that left hand screw is on the last thread when you remove the plate and it drops into the clutch pit you will almost certainly need to remove the engine to retrieve the screw and spring washer, that ‘will ‘ spoil your day !

I always removed both screws and washers completely before lifting the cover off, but what a job to get the left hand screw back in place beneath the starter Bendix and fingers blocked by the gearbox gate, if you have done it you know what I mean.

A very simple mod is to make a new cover from 18swg alloy using the original as a pattern, arranging the holes as shown in the drawing, just remove the right hand screw and slacken the left screw two turns and slide the cover sideways leaving no danger of the screw dropping into the clutch pit. Just oiled my Chummy race in a couple of minutes without struggling.

'Prima' made an accessory cast brass fitting that permanently replaced the original cover having a little flip up lid to drop the oil into the little funnel on the thrust race, replicas are available, but I found on my cars they don't line up with the funnel.

Prior to mid 1929 the three speed thrust race had a ‘Bennet’ oiler without a funnel, so the 'Prima' accessory cannot be used with these races.

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