Thanks to all for your comments and support. I shall be sure to provide feedback on the results of my further investigations ... albeit it may take a while to find sufficient time.

Yet another French lockdown awaits

Can't help with main problem you have but you mentioned about not having right size adapter for the glow plugs, when I changed mine the thing which helped (for me) was using an 8 mm box spanner rather than a long reach socket, additional length really made things easier, especially access to the more difficult last 2 plugs.

Good luck!

Thanks for that mdpslm, I appreciate the help.

I must have phrased it badly, for the problem isn't undoing the glow plugs, I have a long reach socket that does well for that, although I also use an 8mm pipe wrench where needed. No, my issue was an adapter to allow me to use my oil pressure tester as a cylinder compression tester. I suppose I'll just have to get a pukka tester... fortunately that ( unlike the rest of the work ) is not a bank busting investment.

Thanks again

Chris

Chris,

The bolt is very well polished, as opposed to being crushed, cut, mangled.

It must have been in there for a while to get that polished. My guess is 1200 miles seems about right. What could have happened is that it was just rubbing on the valve stem all that time, hence polished vice crushed, mangled, etc.

Eventually it got polished to the point where it was small enough to fit into the space between the stem and the side of the intake port, and THEN it started making noise impacting the valve itself. You can test that theory by seeing how it fits in that space.

Interesting theory merlinj79. Seems plausible to me but, like most theories, it will need testing. I'll let you know when I get far enough to check. At the present rate of progress that should be in time for christmas - probably.