Any one interested in the oiling mods I did?
I think there's two seperate issues that are being addressed with the tubing mod.
I'm not going to swear this is the reason for Guitar's mod as he can surely address that if needed. But from what I can see is done and what I've read/done, the idea would be to reduce the pressure loss from the tappets and limit the responsibility of the oil that is in the RH lifter galley to just the main bearings/lower end. Reason I say that is there is more pressure bled out of sloppy lifter bores than any bearing clearance. So you eliminate the tappet oiling and leakage by tubing. The blocking of the # one main feed from the RH galley is a mystery tho. Seems like it would be fine being fed by the RH tubed galley and you'd want to block the feed from the #1 mian to the left hand galley. Maybe I just read that wrong or forgot in the time that has lapsed and that was what was said...
In any event... The reason for the cross over tube in terms of my engine was to cause some turbulence. To introduce oil volume to that specific area of the RH galley (the #4 main feed passage from the RH galley) from an angle of no more than 45° in the directly opposite direction to the primary direction of flow. I'm not a fluid engineer in even the most basic sense, but I believe the theory is when a fluid is flowing in a straight line and it's momentum is in that direction, some turbulence will slow down the primary directional flow, allowing the fluid to make an abrupt turn easier. I'd also think the added volume of a line right there, and the very, very tiny difference in pressure of the oil in the tube (lower) than the galley, would also cause a fluid to slow down allowing a better turn at that precise point. The tube was designed to make the oil already present in the galley do the job better. Least that was my take and it worked on the one that got it.