Crank cases
- Thread starter jug
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- Nov 20, 2004
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grandpaul said:
That hole was intended to be occupied by the self-destructing (Lucas M3) starter motor drive that the factory wisely chose not to fit in 1971.
Earlier 20M3 Commandos had a hole for the points housing and the early 20M3S timing cases didn't have a hole (see dynodave's crankcase evolution page).
http://atlanticgreen.com/engcases.htm
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My ex plod Mk2a crankcases were machined so thin at the drive side rear to allow the barrel flange to enter that they were split along the side and around the rear......clever bit of typical late Norton engineering was that bit of manufacturing!! Mind you with brain deads previously fitting breathers to the bottom rear of crankcases which returned more oil to the tank than the pump did....deciding they could cast cylinder heads cheaper than the people who had been doing it for decades forgetting the long learning curve required and ending up with heads so pourous they had to vacuum inpregnate them to make them something like oil tight etc etc etc what can one expect....... I cannot remember reading in print the tale of the cylinder heads ..saw a BIG pile of them in a Birmingham celler after NVT went to the wall.....scrap ones £20 each fully finished apart from a tap broken off in a hole or where the inlet drain had broken through into the inlet port or a few bits of fin missing etc..... welding the bloody porous crap was interesting ....so my friendly aluminium welding real expert said but he did not use polite words to describe the experience!!!
IF I remember correctly at Shenstone Mr Negus upon showing me the first of the new crankcases made on the new patterns said they were suitable for both 750 and 820 motors. The clever souls at NVT (MISmanagement) had, so I was told, had all the original patterns destroyed as they believed they would never be required in the future. my money some bloody accountant(if thats how you spell it..I tend to leave one letter out..its a far more accurate a description in the greater majority of cases) had clearly decided that storing old patterns cost money to keeping them dry using a one bar electric fire so they could save money .......
IF I remember correctly at Shenstone Mr Negus upon showing me the first of the new crankcases made on the new patterns said they were suitable for both 750 and 820 motors. The clever souls at NVT (MISmanagement) had, so I was told, had all the original patterns destroyed as they believed they would never be required in the future. my money some bloody accountant(if thats how you spell it..I tend to leave one letter out..its a far more accurate a description in the greater majority of cases) had clearly decided that storing old patterns cost money to keeping them dry using a one bar electric fire so they could save money .......
