I post a while ago about my M21 cases which an extra through casing bush/thrust bit. I assume in was home made, but I just bought a M20 crank and it has one on it. I cannot find it in any parts catalogue.
It pushes in from the outside of the case.
Does anyone have any idea?
Thanks
Matthew
Here are some pics from my case and then the new crank.
On the B31 and 33 there is a spacer that fits in the seal. I would quess it is the same for the side valve engines.so what you have is the spacer.