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ET: Engine (Twin) Series ‘D’ Breather

Bill Cannon

Well Known and Active Website User
VOC Member
Can anyone tell me if the series D timing spindle blocks off the breather hole into the crankcase.
I am thinking of moving my breather from the valve cap to the series C breather outlet so I have a vertical path for the breather pipe.
The outlet on mine is blanked off by a 3/16th BSW bolt, how much can I open this out to fit a stub for a breather hose?
Cheers Bill


Well Known and Active Website User
VOC Member
I have the prototype Black Knight so it is not typical. The hole on that is machined but blocked off. My memory is that in general these holes are not even machined. Instead the casting is left as original and a small bolt fitted which is used to secure the distributor cover.


Well Known and Active Website User
VOC Member
There's no breather hole on my D. That's where the Distributor Cover screws down (see MO32). You'll need to plug up the C breather hole, or the D breather won't work.