Anonymous
Guest
Combat crank case breather.
Teardown of my Combat engine prompted a review of my current breather system. This utilises a 4-reed one-way valve after the LH case mounted breather tower to positively evacuate air and oil away from the crank cases. A catch can then separates air for venting and oil for return to the oil tank using engine vacuum.
My improvement removes the 4-reed one-way valve and better utilises the breather tower to create a one way valve at the crank case exit. Calculation of breather tower ingress, seating and egress ports shows no restriction to maximum air and/or oil flow. Resistance to flow within my improved system is 13g and provided by a single 9/16" steel ball seated within the tower body. Additionally, a stainless steel ball or two balls in the tower may be used to modify resistance, if desired.
One of two convex steel mesh discs was removed (from the breather tower body) but the cap disc is retained to prevent the ball from potentially seating into the cap. The cap mesh has been magnetised to further enhance removal of metallic swarf from the system. Magnetising the steel ball was considered but this may compromise the ball's seating ability if it was contaminated with swarf.
To verify calculations, the dimensions are (mm):
Inlet ID: 18.5
Seat ID: 12.25
Body ID: 19.1
Outlet ID: 12.8
Ball OD: 14.28
Weight: 13 gram
The 9/16" steel ball cost AUD$1.00.
Trolls please note: I have no financial or any other interest in the steel ball manufacturing and distribution industries and provide this information gratis to the Norton Commando (Combat engined and other) motorcycle owners of Earth and beyond - May the Fourth be with you all!
Ta.
Teardown of my Combat engine prompted a review of my current breather system. This utilises a 4-reed one-way valve after the LH case mounted breather tower to positively evacuate air and oil away from the crank cases. A catch can then separates air for venting and oil for return to the oil tank using engine vacuum.
My improvement removes the 4-reed one-way valve and better utilises the breather tower to create a one way valve at the crank case exit. Calculation of breather tower ingress, seating and egress ports shows no restriction to maximum air and/or oil flow. Resistance to flow within my improved system is 13g and provided by a single 9/16" steel ball seated within the tower body. Additionally, a stainless steel ball or two balls in the tower may be used to modify resistance, if desired.
One of two convex steel mesh discs was removed (from the breather tower body) but the cap disc is retained to prevent the ball from potentially seating into the cap. The cap mesh has been magnetised to further enhance removal of metallic swarf from the system. Magnetising the steel ball was considered but this may compromise the ball's seating ability if it was contaminated with swarf.
To verify calculations, the dimensions are (mm):
Inlet ID: 18.5
Seat ID: 12.25
Body ID: 19.1
Outlet ID: 12.8
Ball OD: 14.28
Weight: 13 gram
The 9/16" steel ball cost AUD$1.00.
Trolls please note: I have no financial or any other interest in the steel ball manufacturing and distribution industries and provide this information gratis to the Norton Commando (Combat engined and other) motorcycle owners of Earth and beyond - May the Fourth be with you all!
Ta.