Let's talk a little bit more about the canister oil filter and how the oil enters and leaves the filter.
Olblu49 has an interesting story with how his lines were one way for a period when he first got the truck and then he changed them. The result was a lower reading at idle, or at least an inconsistent reading. What engine do you have, Olblu?
I have a 1956 261 engine in my 37 and when I started running a "Beehive" filter on my engine, the same thing happened. When I added the Beehive and hooked it up, with the inlet at the bottom right from the tee at the guage tie in spot and the outlet to the spot just above the pan rail several inches back - lower readings at idle. Notice I am hooking it up backwards from Olblu, but to the Beehive filter housing as it is marked.
In an effort to fix the problem, I have moved my oil pick up spot to the front of the engine at the outlet galley, normally pluged with a small "drive in plug" or threaded and pluged with a pipe plug (to the left of the timing cover about half way up). The thinking was perhaps the with the filter tied in at the guage it was affecting the oil pressure reading. It did not help and I have been scratching my head trying to figure out why this is happening.
On a related and kind of interesting note, some years back I was told that the oil lines on a 235 by pass filter were to be run reversed of a 261. I have no idea why, but I was told that. I did not believe it and have run mine with the inlet line going into the bottom and the outlet on the side as marked on a Beehive filter.
My reading at idle on a hot day is about 5 lbs. I haven't changed it yet, but now may try it the other way.
If you are using a Beehive filter, the holes are marked with the inlet at the bottom and the outlet on the side. I think that is opposite of the Fram or Purolator type of canister.
I have never found anyone who has been able to give me an answer that makes any sense on this matter.
