Classic/Antique Car Repair: External Oil Pathes on a 53 Nash 235 Six, oil filter systems, hemmings motor news

Question
I am working on a 53 Nash-Healey with the 235 Six.  There are three oil fittings (Ports) on the lower block (on the Distributor-side).  The front port has a plug in it. the center has a "T"...with one tube to the Oil Filter "Out" and an external oil line to the Rockers.  The rear port goes to the Filter "In".  No oil circulates through the filter, when started.  Another Nash 235 I looked at has the center port going to the rocker...the front port to the Oil Filter "Out"....and the rear port to the Oil Filter "In". How do I know which port is the proper port for Oil  Filter In, Out and to lube the rockers? The Nash Shop manual shows nothing on this.  Thanks, Gary

Answer
Ok, lets do a little "007" work here and see what is going on. First the fitting that says filter out, the one that would exit the bottom of the filter should go to a fitting in the side of the block that drops right back into the oil pan. This rig should be using the bypass filter.. The line on the side of the filter nearer the top should the oil in for the filter. This line in most of these older engines had a restriction fitting in the line that limited the oil going into the filter so as not to cause a drop in oil pressure. That line needs to be connected to a fitting on the side of the block that will show oil pressure. To find that fitting make up a mechanical oil pressure gage and test each port with the gage screwed right into the block. If there are two ports that show pressure use one for the rockers and the other for the oil filter. These oil filter systems were by pass systems that only filtered a small portion of the oil unlike the full flow systems that we use today that actually filters the oil being sent to the moving parts. You have a nice rare car and I would suggest that you latch on to a factory manual. My standard answer to any question that starts with "where can I find.." or "I am trying to find..." is to get hooked up with Hemmings Motor news. It is the leading classified ad book for the old car hobby. Check them out at www.hemmings.com.
Brad