F1 8rt oil pressure

Ken Arms

Ken Arms

Well-known member
Anyone running a flattie of this vintage that can tell me what to expect for oil pressure, my 52 f1 pessure when cold will be about 20lbs at idle and tickle on 30 when you rev, once engine is at temp at idle the gauge barley moves off 0 and at rev will go up 10-15. I have no clue how fresh anything is in engine since I recently purchased the truck. I get some valve noise once hot and what I think is blowby out of oil fill. Im running straight ND 30 wt oil. Engine runs just past halfway mark on temp gauge. Thanks Ken
 
I also have a '52 F1 - my start-up oil pressure will be about 40 but this drops to 20 after it is warmed up - a little under 20 at idle and a little over when "cruising" after warm up. I use Rotella 15/40 here in Little Rock, AR.
Fairly good compression on all cylinders and it basically runs really well.
 
Oil pressure in flatheads is as varied as the number of opinions you'll get on the subject.;) We've got a '51 F-1, that we rebuilt about seven years ago, the Flathead has close to 25,000 miles on it and at cruising speed (55 to 65mph) it gets 55 lbs of oil pressure. Our '39 CS with a stock 221c.i. Flathead with well over 50,000 miles on it gets between 15 and 30 lbs of oil pressure on any given day and has for the last 20 years. Our '47 with a "built" 59A gets 35 to 40lbs of oil pressure at normal temp. on the highway and our '39 Lincoln Zephyr HV-12 (that was rebuilt in 1952, yes, 1952) gets between 15 and 35 lbs at normal operating temp. I had a '46 Ford that never got over 5 to 10 lbs of oil pressure no matter what the temperature or speed, and that Flathead never gave me any trouble. As far as smoking from the blow by or breather, that's a normal occurrence. As some will say, "if it ain’t smokin', it's broken". I use Castrol 20/50 in all our Flatheads and have installed top oilers on both the '39CS and the '39LZ. I use MMO in the top oilers. Sorry for the long winded response, the bottom line is, drive it and enjoy it, don't worry too much about the smoking and oil pressure.:)
 
My 8RT runs in the same range as you list. I even have a new Melling hp pump in it. These engines were never a high pressure engine.

Barry

50 F-1
 
The engine in my pickup runs about the same. About 5-8 on an extended hot idle and about 20 going down the road. It hasn't changed in 4 years. Sounds good and runs good so I don't plan to do anything to it. I am running 20/50 and STP.
 
Check your sending unit, Ford has 2. My 39 had zero oil pressure when warm and the previous owner swore up and down he'd driven it years that way. Simple check with a mechanical gauge verifed 30# when warmed up at speed and 10 to 15 at idle when warm. Changed the sending unit, and pressure reading is "proper"
 
I did check mine with a mechanical guage, even took the filter out of the system. The mechanical verified the the stock guage.
 
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