1973 Z1 Maui

Yes, it’s “piece 30”, both are there.
Another pump is on the way, I’ll compare them and try it out.
im also going to take another look at the gaskets, the “feather test” seems to indicate there isn’t a restriction but I’ll check anyway.

wrote:

cams and bearings in, no valves. All spun very freely.
spun it with the starter and a strong battery, oil light went out, never budged the pressure gauge needle.
took gauge off, put on a clear tube, spun it again, oil went up tube. I never saw oil at the cams. I took the dynamo cover off and looked down the other end of the gallery, all clear. Pump is either too weak to push oil up or I have a blockage in the cylinders or head that has eluded my many inspections. 

Can you repeat the same tests at the bung next to the oil pressure switch, assuming the gauge is good (which the lack of flow would suggest it is) it seems strange that you have enough pressure to put the light out but 200mm later at the end of the main gallery there is nothing ? I don't know what pressure the switch operates at but I wouldn't expect it to put the light out with almost zero pressure (there must be a little or there would be no oil movement at all in the gallery) I would forget about the cylinders or head at the moment until you have the correct pressure in the main gallery.

wrote:

I don't know what pressure the switch operates at but...

I don't think it's really a pressure switch in the traditional sense. It's more of a flow switch. Moving oil just pushes the plunger out of the way.

Have you looked at the oil filter. Or the filter bolt, was the bypass removed, if so was it assembled correctly. I’d keep working my way back towards the pump to see if and where you get good flow. Like others have suggested can you take the housing off that holds the oil pressure switch and rig up a fitting at the top of the S right above the oil filter and see if you have pressure there


EDIT, Oil pressure is 2.8 psi at 3000 rpm. There is no why the starter will spin the engine at 3000 rpm to test pressure. 

A stuck open or weak spring in the safety bypass valve?

 

I now have another pump, I'm going to compare it to my original just to see if there is anything significant. 
I'll check the oil filter assembly along the way. 
The "pc30" o rings (they actually aren't round) are there and new.
I'm also going to do another check of the base and head gaskets to be sure there isn't a blockage of some sort.

Good luck. You deserve a break!

I checked the second oil pump and it measures exactly like the original. Now I have to check the base and head gaskets to see if there is something there to divert oil away. 
 

This should ease your mind with respect to the system pressure.  I copied it from a maintenance and training manual for Z1's.  Note the hen scratching near the bottom.  I don't know who did that, perhaps slmjim knows.  In any case the important info is that the system operates at low pressure , and that the light should come on if pressure is too low.

 

wrote:

I checked the second oil pump and it measures exactly like the original. Now I have to check the base and head gaskets to see if there is something there to divert oil away. 

 

I still think your problem is with the supply into the main gallery before it goes up the block to the head, the clear tube test you did didn't show a huge delivery. Did you try repeating the same test at the switch housing blanking plug ?

I like Wookies bucket test. Remove the transfer tube. Make a plate to fit the block will a hose barb fitting. Adapt a fitting to a clean bucket Fill the bucket up, hold it high above the engine and oil should flow up the block to the head. Way easier the tearing off the head and block.

I connected an oil line to the gallery where the gauge would go and fed oil in with air pressure. It didn’t go to the head but I think I could not deliver enough volume to overcome the losses down to the bearings. I blocked off the passage back to the pump.