Joea,

My oil pressure reading is in the same place as yours and it has served me well. The Fram oil filter is junk. In fact I have found the NAPA (Wix) or the Motorcraft filters to be the best. However, I now use a System One re-useable filter and I highly recommend it. It is made in your own backyard (Tulare or Visalia, I think). Cost is about $100.00 but it is a one time expense and there are plenty of advantages to seeing what is in the oil you are taking out of your engine.


Clois

If the order is oil pump, pressure sensor, oil filter, cooler, back to engine the pressure will read higher as the filter and/or cooler resistance increases (false reading).

If the order is oil pump, oil filter, cooler, pressure sensor, back to engine the pressure will read lower as the filter and/or cooler resistance increases (true reading).

It's best to have the oil pressure sensor the last guy in line before the oil goes to work. If the sensor is in front of a filter or cooler it will read higher than the pressure experienced by the engine. The more resistance in the filter the higher the reading (a bad thing). Given enough resistance in the filter (clog) or cooler much of the oil will flow through the bypass while the pressure reading will be quite high. Flow, however, will be quite low.

Bob

I'm actually not sure what order the sensor would be in...it is in the top of the filter adapter which I assume is AFTER the pump and BEFORE the filter.

(Edited)...Actually top of the filter adapter should read the pressure going back into the engine right? Wouldn't that be last in the chain?

Generally the sump oil is sent right to the filter and then the engine.

Oil pressure is best taken at the furthest point from the pump.

The pressure port in the top of an FE oil filter adapter is downstream of the filter element and cooler. It connects to the passage which sends the oil to the motor, after it has already been thru the filter and cooler. When you connect your guage to that port, you are getting the pressure after the filter, after the cooler. Your pressure sensor is the last thing the oil sees before entering the block. The reason why Joe saw an increase is the difference between Fram and wix filters, many others can confirm the same results.

So, in short, you are getting a "true" reading of the pressure as it enters your block.

YAHOO! The cooler adapter may have also played a role here. I really don't care...I have the pressure I was looking for now!

Interesting...

I had a similar (though) opposite experience. I used Fram filters (2 one quart filters) during break in for my 427 with a HV bluprinted oil pump and a HP bypass spring in the block.

I got 85-90 psi at speed (over 2500 rpm) and a low of 50 or so at idle. After 500 miles I went to Bosch oil filters. I got 70 psi and 40 or so at idle. Same brand oil, 25/50 Valvoline, same temp. It wasn't gradual... Bam it just changed.

I switched to bosch after reading a thread about Fram and some of the specs from a website that did an exhaustive analysis of the filters contents and build materials. Napa Gold (WIX) and Ford FL-1's were among the highest rated. Mobile 1 filters were rated pretty high too.

It may be Fram just has really bad quality control. I can't imagine a 30% increase or in my case decrease from using one brand to another. I'm almost ready for an oil change again. I have a pair of Moble 1 filters and was going to wait for 2500 miles on my new engine to switch to synthetic 20/50. I'll let you know what happens then.

Well interesting got scary...

It's February in California and that means spring time. We had about 12 inches of rain in 6 weeks and the sun is fianlly out.

I took my car out for an extended ride, about an hour or so. The oil pressure has remained the same since I changed the oil last, less than it had been before I changed it, but occasionally dropping to 30 psi at 900 rpm, a little lower than the 950 the big cam 427 will tolerate.

About 40 minutes into my drive I noticed the oil pressure steadily drop at speed, 2500-3000 rpm it had generally been constant at 50-60 psi, maybe 70 max. It got to 45 psi at 2500 I became concerned. I pulled over and checked it. I had oil on the stick. Back on the road it seemed the pressure was somewhat unpredictable. Sometimes it would climb to 60 at 2300, but drop steadily at 2600. At 2800 it seemed steady at times and unsteady at others.

I got back into civilization and the water temp began to rise, not too high, but hotter than it had gotten all winter, 165-170 or so. I pulled up to a stoplight and the oil pressure dropped to 18 psi. I resisted the impulse to shut it off. It stopped dropping and climbed slightly.

Well, scary isn't quite the word. The day I put the oil plugs in flashed in my mind. Gessford high pressure bypass spring, check. Bluprinted HV oil pump check. I thought again about the Bosch filters I put on back in the fall. Hmmm...

So I drove to my local auto parts store. The one that sells the Bosch filters and the Fram filters I used for start up. I decided to see what would happen if I put a pair of Fram filters back on.

I pulled into my garage and shut off the car, waited a minute and started it back up. 22 psi at 925 rpm. I jacked up the car, still hot and switched the filters, and restarted the car (2 quarts low) it went straight to 45 psi. I shut it down and replaced the 2 quarts of oil lost during the filter change. I restarted the car. 50 psi at 925 rpm. Blip the throttle. 65 psi at 2000 almost 70 at 2500.

I took it for a ride everything still hot. The car idles at 50-52 gets 70 at 2600-2800 and about 75 at 3000-3200 I was in the neighborhood and it was after 7 pm I didn't want to wake up Turk so I left it at that.

What does it mean? Well, I guess it means my car hates Bosch filters.

I plan on switching to full synthetic at 2000 miles. That will be in a couple months, hopefully less. I have 2 Mobile 1 filters I bought back when I thought I might switch straight to synthetic after initial break in. They tell me it's better to wait a couple thousand to fully seat the rings.

I'll be using Mobile 1 20/50 most likely. Royal Purple is sold locally now so maybe I'll try that. Either way I think I'll use Motorcraft FL-1 filters and see that happens.