I've been at the computer for a while now and have just applied everything I have learned.
I had a EJ20 standard crankshaft to spare so I have modified the front main journal to see if its possible. Here is what I tried to do-
1- Single oil supply hole on main journal which would be used with a full groove main bearing shells.
2- Hole drilled so oil enters the oil hole in direction of rotation, this makes oil pickup easier (doesn't have to make a 90 degree turn in order to enter the crank)
3- back side of oem hole relief welded up
4- Oil hole does not pass through the centre of the crank therefore reducing the effects of centrifugal force acting against the oil flow
5- Oil lead in groove in direction of rotation, this gives the oil time to enter the groove before being scooped up by the hole.
6- Oil supply hole same diameter as oem 5.5mm.
7- New oil hole drilled to intersect the original hole approximately at the web.
8- Pressed in a steel pin to block off the original cross drilled oil hole.
I think this proves it is possible, I used one of the old hole positions so I didnt have to drill the bearing surface with a new hole.
Looking at this design I feel its a much better option for high rpms.
Whats your opinions on this design -