Thanks for the info Renn, I haven't seen those before despite working on quite a few old brit engines myself. The way we always looked at it was "its designed to leak as a form of corrosion protection" I have never yet found an MG with a rusty sump
In other news unfortunately I won't be getting +1mm valves atm. I bought some second hand from pschmidt that he pulled from a spare head but unfortunately despite his machinists assurances, they're toast. He has been very kind and refunded the total amount despite me telling him to keep the shipping costs (thank you very much Patrick).
The reason I bring this to peoples attention is they are toast in a very abnormal way and I really want to know what happened to them. The exhaust valves look reasonable, there is no shiny seat margin on them but they look like they might lap in or at a push need grinding. But the inlet valves are frazzled. All of them have grooves in the seats and on some the outer 0.5mm has been completely eroded.
WTF happened!? I have never known intake valves to go before the exhaust.
Also take a look at my now not so standard flywheel.
Spent a few hours playing on the big centre lathe at work and managed to add 4lbs of lightness (now weighs in at 16lbs, not bad for cast iron) with possibly more to come if I feel the need. Now I just need to balance it.