Oil issues

[2trux]

I am working on a 90 B2. It seems like there is insufficient oil flow to the right side of the engine. The lifters don't seem to be staying pumped up, and there seems to be very little if any oil in the rocker shaft.
I have checked the oil pressure with a gauge and it is running at 45 - 50 psi. I had just replaced all the lifters because #1 exhaust was collapsed. When I crank over the engine with the rocker rail removed I don't see any oil come out of the feed hole to the rocker shaft.
Is there a place to find an oil flow diagram? Does anyone have any ideas where to start, or troubleshooting techniques?

Thanks

 

[Uncle Gump]

I've heard that when the cam bearings wear the lifters starve for oil... because they come after the cam bearings. I think there may have been a TSB about it years ago.

 

[2trux]

Thanks, I will take a look at that. I will be pulling the engine soon. This engine was rebuilt 4 years ago with new cam and bearings, maybe the bearings rotated and blocked the oil holes.