I recently put a non-USA distributor in my 73 FJ40. It ran great and had good oil pressure for several days, then one day when I started it up there was no pressure on the guage. I spent today trying to figure it out, but no luck. I pulled the distributor and tried several times to get it seated further in the housing to try to make sure it was seated correctly. I measured the old distributor and it had a little longer shaft. When this did not work, I rigged up a screw driver on a drill to see if that would show pressure. With the key on there was no pressure with the drill. I then took the oil pressure regulator apart to see if anything looked strange. Honetly I am not sure if it is fine or not. The spring seemed fine, but the adjustment screw goes in most of the way without any pressure. My book does not give any measurements for me to tell how far it should go in before the spring pushes back. Any advice? What do you think the chances are of the oil pump failing like this? Is it more likely something with the guage? Is there anything else I can check to track this down?