I now have a nice clean cylinder head cover, cylinder head, and cylinder . the picture on your left is before cleaning. On closer inspection of the valves and valve springs i have decided to completely renew these items as they are not expensive and it seems like a good time to do so. when these new valves arrive i will grind them into the head. As for the pistons rings i have removed these from the piston and inserted them into the cylinder to check for wear and the gap was three times larger than the minimum requirement so i have decided not only to replace the rings but to replace the whole piston using a standard 60mm mahl repacement which cost £25 from british heinkel club . There was also considerable wear to the connecting rod bush so i will also replace this so that everything is nice and tight. I will now have to try and get the old bush out which can sometimes be difficult