Rocker Shaft Orientation

Status
Not open for further replies.
Dunstall tuning notes say that the earlier narrow gear pump was "the better unit for racing..." but modified to take the wider later pump scavenge gears.

late pump gear width-feed.250"/scavenge.416" (measured .401.406.412) feed-scavenge ratio 1.666

early pump gear width-feed186"(3/16")/scavenge.312"(5/16") feed scavenge ratio 1.666

dunstall
early pump gear width-feed186"(3/16")/scavenge .416" feed scavenge ratio 2.236

I own only one early narrow oil pump. It is a zinc/potmetal body. Did they make narrow gear iron ones?
 
Reference is made here to 3 start & 6 start gear.???..I take it this is to do with the gearing ratio of the pump & crank scroll gears. ?
 
Reference is made here to 3 start & 6 start gear.???..I take it this is to do with the gearing ratio of the pump & crank scroll gears. ?

Yes.
Rocker Shaft Orientation


 
The 6 start gear ran the pump at twice the RPM's of the 3 start so double the volume of oil if there was no back pressure.
 
late pump gear width-feed.250"/scavenge.416" (measured .401.406.412) feed-scavenge ratio 1.666

early pump gear width-feed186"(3/16")/scavenge.312"(5/16") feed scavenge ratio 1.666

dunstall
early pump gear width-feed186"(3/16")/scavenge .416" feed scavenge ratio 2.236

I own only one early narrow oil pump. It is a zinc/potmetal body. Did they make narrow gear iron ones?
Does this take into account that from mid 1966 Norton opened up the holes and fitted a bigger holed oil pump feed block to the crankcase?
 
Status
Not open for further replies.
Back
Top