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Discussion Starter #1
I need to draw on the knowledge base here in a bad way.

Nationl Machine rebuilt my "M" engine a few months ago. I discovered after running the engine for several hours that (post build) no oil was getting to the head.

Got plenty of oil pressure, the passages that we can access are clear, but no oil is getting past the rear cam baring to the gallery that feeds the external tube going up tp the head.

I'm beginning to wonder if sometime in the many years of operarion someone install the wrong cam or some other incorrect part that is blocking the oil path.

Can anyone provide (based on experience) how the oil feeds through the rear cam shaft gallery?

The shop has the engine disassembled and does not see a passage out of the cam baring into the rear oil gallery.

Help if you can please? We are really struggling here.
 

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Might have the cam bearing indexed wrong, blocking the oiling hole to the passage would be my initial thought.

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Discussion Starter #3 (Edited)
The bushing / bearing at the rear end of the cam shaft has a hole in it that has to align with a slot in the cam journal (machined into the block). That slot runs from 12 o'clock to 3 o'clock when looking and the rear of the block. So the indexing of that bearing is pretty forgiving (12 to 3 oclock for the hole position). Hard to mess that up, and the machinist confirmed that it was indexed properly. It appears that the only way oil can get into the gallery at the rear of the block (cam shaft end), is to seap past the cam to bearing gap. When oil pressure is applied to the system via external means; very little oil is getting past that bearing into the gallery and hence the "problem". Just enough to lube the bearing itself. The shop has ordered bearings from 2 different suppliers (one being Clevite) and thay are alike.

So the question is why so little oil getting through to feed the gallery and tube going to the valve train? Is there a hidden oil passage around the bearing we have not discovered or addressed ?

Has anyone ever had to tap the oil passages ahead of this bearing to feed the valve train?
 

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All of the passages gone thru with brushes or wire? Tried pulling oil pressure fitting and applying air pressure there to see if it travels thru the galleys?

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Discussion Starter #5
Other than pressure pushing oil past the rear cam bearing, does anyone have expectations of the oil getting to the head (valve train) external feed tube via another path?

Please ....any ideas?
 

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Discussion Starter #6
All of the passages gone thru with brushes or wire? Tried pulling oil pressure fitting and applying air pressure there to see if it travels thru the galleys?

Sent from my hammer and chisel using Tapatalk
We have applied oil pressure and air pressure via external means using the port you mentioned, but not much oil gets past the bearing. Everything is as clean as a new dollar.
 
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