Oil Pressure

[SCOBRAC]

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.