Ford 860 - Little to no oil at the rocker arms

I just got my Ford 860 back together. Getting good oil pressure at the gauge (45-50 psi @ 1/2 throttle). At almost full throttle, there is only a few drops of oil coming out of the drain-back tube at the rocker arms. Nothing from the pee holes on each rocker. I'm worried to keep running it till I figure out if there is a blockage and if it can be cleared. I would have expected some oil dripping and running along the length of the rocker arm assembly, but nothing! I did try to blow back through the feed tube, but couldn't get any air to go backwards through. (maybe I shouldn't be able to?). Is there a process I can use to verify the oil passages are open? I did install a new grommet on the end of the feed tube and it is firmly seated into the block. Any insight or root cause process would be much appreciated.

Thanks

It's been too long since I had one running with the valve cover off to remember how much oil is coming out of
the valve train while running but I do recall that it was messy to adjust the valves while running with the oil
flying around. I do know that it only gets 'pulses' of oil while running. The cam must be in the correct
location to open the holes in the passages to allow oil thru so blowing air back thru would only work if they
are lined up. Sounds like you either have an internal leak or something is plugged. Sorry I can't be more
helpful! Greg NE

(quoted from post at 18:47:14 07/10/20) It's been too long since I had one running with the valve cover off to remember how much oil is coming out of
the valve train while running but I do recall that it was messy to adjust the valves while running with the oil
flying around. I do know that it only gets 'pulses' of oil while running. The cam must be in the correct
location to open the holes in the passages to allow oil thru so blowing air back thru would only work if they
are lined up. Sounds like you either have an internal leak or something is plugged. Sorry I can't be more
helpful! Greg NE

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That's what I was thinking. Should be oil splashing around. I had cardboard set up to limit the oil splash down the side of the tractor, because once warmed up, I was going to reset valve clearance. But nothing but a slow drip from the exit tube. Thanks

Pull the side cover sometimes the feed pipe work loose.

Agree with Kirk, first check the feed pipe making sure the seal is in place and seated in the block.

(quoted from post at 21:47:14 07/10/20) It's been too long since I had one running with the valve cover off to remember how much oil is coming out of
the valve train while running but I do recall that it was messy to adjust the valves while running with the oil
flying around. I do know that it only gets 'pulses' of oil while running. The cam must be in the correct
location to open the holes in the passages to allow oil thru so blowing air back thru would only work if they
are lined up. Sounds like you either have an internal leak or something is plugged. Sorry I can't be more
helpful! Greg NE

Click to expand...

When I pulled the feed tube out, it was seated in very tight and the grommet was still in the correct spot. I like the advice to pull the side cover though. Not a bad idea to put my eyes on it. Maybe something weird going on when seated.

Thanks for the oil flow schematic JMOR. That helps a lot. I'll keep you posted on what I find.

Thanks

JMOR, Quick question - Was the yellow highlight on the schematic specific for my investigation? Looks like there are 2 plugs from the casting cross-drill process. That area does not look like it is part of the feed tube area (?). Thanks

Update: So I pulled the side cover and the rocker feed tube is securely seated and sealed. I blew air into it and almost no flow. Next I pulled the oil filter and rotated the flywheel until the cam shaft lube hole lined up with the oil feed hole. I blew air through rocker feed tube and there was no restriction. Air flowed freely to the oil filter fitting. I was hoping to blow out some debris or sediment, but nothing. I blew air from the filter side as well and no restrictions there either. I pulled the bottom pan but the mosquitoes ran me off. I'll check for any leaks in the pump assembly or pump pipes tomorrow to see if there is any leaks in that area. Nothing obvious visually.

Any other suggestions would be helpful. I'll send another update after next steps.

Thanks Kurt

(quoted from post at 16:54:45 07/11/20)
JMOR, Quick question - Was the yellow highlight on the schematic specific for my investigation? Looks like there are 2 plugs from the casting cross-drill process. That area does not look like it is part of the feed tube area (?). Thanks

Click to expand...

o, just colored for some older questioner. Plugs are as you say.

Did it appear to be getting oil before it was worked on? Any sludge in the rocker arm tube? You could probably fashion a short stand pipe or fit some rubber hose in there to see if your getting the upward squirt.