I recently installed an oil pressure gauge on my 55 Fairlane.  It has a 272 that was rebuilt prior to me owning it.  I installed the fitting for the gauge in the block, just to the right of the oil filter and used a new Autometer kit with new fittings and nylon line.  Upon startup (cold), the gauge read about 70 psi which seemed high to me.  I drove for 15-20 minutes, and the gauge read 60 psi the entire time while driving.  It settled in about 40 psi at idle.  The next time I took it out for over an hour, including getting up to highway speed (70-75 mph) to see what it would be when the engine was hot.  Running pressure remained at 60 and idle leveled out around 30 psi.  I guess I was pleasantly surprised, but I wondered what everyone else has for cold, running hot, and idle pressures.  I'm interested because my 292 in my 59 F100 is always 60 cold, 40 running hot and 25-28 at hot idle.  I've been running that motor for about 8 years since I rebuilt it.

Soffian Adam
Jamestown, NY
59 F100, 55 Club sedan

30/60 sounds ok to me. Make sure that your gauge and sending unit are both 6V or 12V. Don't mix 6V with 12V. However, if you converted your 55 to 12V, the 6V gauge and sending unit should work ok. 

Those oil pressure numbers are similar to what I see on my 1955 Customline with the 272 engine.  This is with Trop-Arctic 10W-40 oil which has been used in the car since it was new.

Lorena, Texas (South of Waco)

Sounds good to me. He has a mechanical gauge with a nylon line to it. No electrical sending unit to it. Prety much fool proof as long as the line doesn't leak. Electric guages with a sending unit don't have a line to leak but the sending unit and the gauge both have the potential to fail. Personaly like to run the idiot light and a gauge.

Had a similar situation, but only ever had the factory idiot light. I went through the heads, my "rebuilder" didn't do much of anything with the rocker arms, shafts &c. Among other things. Very expensive lesson. Anyway, eventually decided to take a closer look, there was at least clear evidence of new rod and main bearings.

The factory shop manual spec listed for Y-Block is 35 to 55 psiHOT at 2000 RPM. At a cold startup this particular engine measured 57 psi with a 10w-40 Napa branded valvoline, and 35 psi at hot idle, 60 psi hot at 2000 RPM. I did switch to a conventional 10w30 oil, suitable for flat tappet engines. Didn't bother to measure it again but it should bring the pressure within limits.

I "assume" but I'm not sure, that a functioning oil pump bypass valve should limit the oil pressure particularly at a cold startup to something less than ~ 60 psi?

Thanks for all of the responses.

55Blacktie, as Slumlord mentioned, the gauge is strictly mechanical, so there shouldn't be an issue.  I was told that it was converted to 12V up to the starter.  I don't know exactly what that means.

Ted, thank you for the confirmation.  I have only added, and finally changed, the oil using the Brad Penn 10W40 "green" oil that is designed for flat tappet engines. I believe that Isky also recommends this oil.  I've also been using it in the F100.

Slumlord, I had wondered about my gauges since I bought the car.  The previous owner was in the process of having the interior completed, but it looks like they never got to the dash.  Bulbs aren't there, no lights work, bad wiring, etc.  When I was installing this oil pressure gauge and installing a spin-on oil filter adapter, I discovered that the oil pressure sender wire for the idiot light didn't go anywhere!  The wire was cut and just sitting there, so that explains why I never even had an idiot light.  I'm hoping to work on that this winter.

Tedster, my engine is running about 2500 RPM when the gauge is reading 60 psi, so that sounds about right with your car.  From what everyone has said, I think I'm in the right ballpark.  

Thanks again.

Soffian Adam
Jamestown, NY
59 F100, 55 Club sedan

My 292 is 40 at idle and 70 hwy cold and 25 idle - 55 hwy hot. I’ve got Dakota Digital electric gauges.

I use 10w30 weight oil in my 292.  I didn't see the need for anything heavier.  My motor has less than 3,000 miles on it's rebuild.  It holds about 60 pounds of oil pressure cold and about 30 pounds hot at idle.

When the previous owner said, "12 volt up to the starter" he most probably meant that he left the 6 volt starter in place.... which will work - a lot of guys did that. The 12 volts will give that 6 volt start a little more "umph" when you bump the key over.

Daniel Jessup

Lancaster, California

aka "The Hot Rod Reverend"
check out the 1955 Ford Fairlane build at www.hotrodreverend.com

My TBird was converted to 12 volts when I bought it.  It still has it's original 6 volt starter.  The 6 volt starter fires the engine instantly. The person who rebuilt it for me told me to use it until it gives me trouble.  So far, no problems.