View attachment 1715562818 I asked one of the engineers at my company who has plenty of years in such matters. He looked at my sketch and told me:
1) Double end feed is better if you can do it.
2) There is no such effect as two columns of oil 'smashing' into each other. Fluid is....fluid.
3) Oil flow as shown is a pressure function. If you are able to show 50/55/60 PSI in a manifold (or whatever number you like) the flow is a direct function of that pressure. Only when you fail to maintain that pressure will flow begin to suffer.
4) As long as the surface area (diameter) of the manifold is about 2X the surface area of the sum of the branches, you will see very little pressure drop from branch to branch, no matter which two branches you are comparing.
He told me he did hundreds of flow tests on a similar manifold with 6 branches and the pressure drop between any two branches would be very tiny, like .01PSI, as long as the manifold were sufficiently big. These tests were done using very sensitive meters and were 'certified' for aerospace use. In other words, very accurate and calibrated.
He said the flow between branches in the above example would be the same 'because it had no reason to vary'.
So...if that's all true...the galley is .531" dia which equals .2214 sq in. The factory 1/4" passages, times four, equal .196 sq in.
That tells us the galley is undersized. What's worse, if we enlarge the passages to 5/16", our sum goes to .305 sq in. which exceeds the 'capacity' of the galley itself.
Of course, our lifter bleeds are only making matters worse.
Double feeding the undersized galley becomes all the more beneficial.
What we need is a bigger galley.....maybe feed two mains off the left side and two off the right?
This assumes the passages are unobstructed, which of course they are not (we think) because the crank/cam act as a partial blockage.