Exhaust Nut

Had to cut into the nut to get it loose. That does not matter since it is wery corroded and has to be replaced anyway. Thread is 20 TPI and I measured the outer diameter to 44.3 mm which I presume is  1¾ inch (44.45mm).

The new nut will be made from brass or brose. it will also be made for use with a hook wrench insted of a regular spanner.

At the same time I dismantled the valve gudes and destroyed my valve guide tool that was special made for another engine ..