These photos provided by Manfred Jaeger in Germany. It is an MBG 1800 5-main bearing engine block being machined for addition of mechanical tachometer drive. It must be machined in the area noted by the red arrows. At one point low at the rear there is insufficient material to provide a complete mounting surface for the tachometer drive housing. So it was machined a little deeper, followed by addition of a thick spacer plate for correct positin of the tach drive housing (then needing two paper gaskets). This is the first time I have seen a 5-main bearing block successfully machined for the tach drive.


Some 3-main bearing blocks were not machined for the mechanical tach drive, but at least those did have material in the right place for more convenient machining. Machining dimensions are given below. Click for larger images.