Using large quantities of Oil? Part 2 (and ticking over roughly)

When I rebuilt JTM50 nearly 17,000 miles ago I fitted new original type, waxed string, Valve Stem Seals. and  until recently they controlled oil consumption adequately. However for the last few thousand miles an increasing amount of smoke has been coming out of the exhaust, culminating in clouds of the stuff being clearly visible in the rear view mirror as I accelerated away from the bottom of steep hills. The car still used very little oil on long Motorway journeys but it was a different story when I was driving up and down the steep hills of the Stroud Valleys.

I decided that I’d better remove the valve springs and examine the valve stem seals.  The umbrella seals that  I’d previously fitted were fine but the seals themselves were in a very poor state, only about 20% of the original string remained and none of the Russian Tallow that bonded them together. Richard Treacy and Bill Coburn had been telling me for some time that this would happen but I don’t like changing any aspect of my car from the original R-R specification without good reason and Norman Geeson has had no trouble with his.

Richard Treacy had very kindly sent me a conversion kit that he’s put together and that is now being sold by Introcar. It comprises of a set of modern synthetic synthetic seals that press over the top of the guide and are used on the latest V8s and spacers to replace the part of the “Top hat” that keeps the inner valve spring in proper compression.  You can see these in the accompanying illustrations.

The tools that you’ll need to do the job are shown in the pictures and comprise of something to hold the Valve shut. In my case I’ve removed the ceramic part of an old spark plug, drilled the the body so the hole has parallel sides and then pressed a length of brass bar into it and drilled a 1/4” hole through the middle, then I slid a piece of 1/4” steel rod through it and bent it as shown in the picture. To drive on the seal I’ve used and old gudgeon pin and the spring compressor is available from most Automotive Tool Suppliers. I’ve found it best to modify it so both legs are the same length as it’s easiest to lift off the plate the springs sit on as well.

The result is a miraculous transformation, because the modern seals keep the oil in the guide and don’t allow the engine to draw air oil through the guide when it can’t get it from the Carburetors, the smoking has stopped, the engine ticks over like a Steam powered job and it pulls from 8-10 mph cleanly in top gear!

As I’ve already said I’m not keen on modifying anything without good reason but in this case I think this is a good idea because the old seals simply don’t last long enough. The Australians reckon about 10,000.