As part of my lubrication works I made some oil light pistons to replace the standard machined cast originals shown in the bottom picture.





The original had a rounded tip, whereas mine had a threaded hole, which was part of the oil relief valve assembly, and I couldn’t really alter this unless I made a two part piston.



There was a concern that this nosing or tip, despite being rounded similar to the picture below …



… would still abrade the oil light wooden button, and cause problems further down the line. To negate this I started work on a one off two part oil light piston assembly.

First I had to replace the set screw and create a guide for the relief valve spring. I made this part in brass using the lathe from a piece I had lying around that I was going to use to replace a missing foot off my favourite briefcase!



Then cut down a replacement oil light piston, and put them together, to look like this.



This was the finished product within the camshaft gear...



…and here is a close up.



UPDATE (2011) Link to this post

It turns out this wasn’t necessary, as upon examining another early engine, with this rounded oil light piston tip fitted there was no wear to the wooden block, so this work wasn’t required, but at least there is another option for those that don’t believe me.