Troubleshooting Oil Pressure

[bobsemp]

I have an '82 sportster that is not getting oil to the top end;
the oil pressure light goes out (while cranking and running) but
apparently this was misleading as the net result was a $550
valve job. In trying to troubleshoot the problem, I'm trying
to see if there's a blockage or if the pump is broken or ???

Anyway, for my lead off question, how much pressure should
be coming out of the oil pump as the engine is cranking over,
and should it build? It doesn't seem to be more than enough to
push the oil out of the pump, but with no real pressure.

Help please!
Thanks

 

[Fisher]

I know this is an old post but here goes anyway.
The best way to check the pressure is to remove the sending unit and install a test gauge.The pressure must be tested on a running engine.Your manual will answer how much at what RPM.
The top end receives oil form the outside oil lines on an Iron head like yours.They can be blocked by debris or sludge (rare) and starve the top end.in the end you'll need to start at the pump and work your way up through the system.They don't have much pressure or flow at cranking RPM so that's why it's to be tested on a running engine.How old are your oil lines?What kinda shape's the oil tank in?There are many things that can cause oiling problems.Start at the tank,make sure you have oil.Then to the pump.