@Phil Bleazey
The ball valve is placed close to the bonnet. When closed, the bonnet cannot be closed because the lever is in the way.
@rockabilly john
The tank is unique. Also important are the plates on the inside, so that the oil cannot leave the outlet in a curve.
I can supply a detailed drawing as well as a schematic.
I will create a separate thread for this topic. (If I know how)
