8N Ford Oil Pressure

Jim R

Member
I recently bought a 1948 Ford 8N Tractor, my first old Ford Tractor. It is believed to have a fresh engine overhaul from a previous owner but not exactly sure what was done. I changed the oil and put in Rotella T 15W40 which I use in all my tractors. It seems like it takes a long time for the oil pressure to come up after starting it cold, especially in colder weather. Sometimes it may take as long as 15 seconds or so for the oil pressure to come up. Should I be using a lighter weight oil, or is this a common thing among 8N's. Thanks for any advise!
 
(quoted from post at 16:52:34 03/19/13) I recently bought a 1948 Ford 8N Tractor, my first old Ford Tractor. It is believed to have a fresh engine overhaul from a previous owner but not exactly sure what was done. I changed the oil and put in Rotella T 15W40 which I use in all my tractors. It seems like it takes a long time for the oil pressure to come up after starting it cold, especially in colder weather. Sometimes it may take as long as 15 seconds or so for the oil pressure to come up. Should I be using a lighter weight oil, or is this a common thing among 8N's. Thanks for any advise!

The flat head oil pump is not the strongest performer in the world but you should get a solid oil pressure indication almost immediately once the engine starts runniing. Even just cranking with the starter motor should move the needle. You have an issue and unless the temperature where you live is well below freezing it's not likely the 15W40 grade oil is your problem. Personally I prefer 10W30 for general year round use and you can try that just to see what if any difference it produces.

I always cringe when I hear somebody with a tractor for sale say "the engine was just overhauled". To me all that means is it wasn't working right and somebody tried to fix it. Maybe they knew what they were doing and maybe not.In your case it sounds like "not". In any event the first thing to do is determine if the oil pressure is really that slow to build or if the gauge is faulty.

You'll probably get at least one dissenting opinion but IMO any engine that runs for 15 seconds after start-up without oil pressure is rapidly digging it's own grave.

TOH
 
Not all that uncommon for an oil pressure gauge to start reading pressure that slow. Bet if you pulled the oil line hook up on the side of the engine you would find you have oil there a lot faster then that 15 seconds. Yes a thinner oil like say a 10W30 would maybe come up faster but again it takes time to have a gauge start reading and depending on the gauge maybe slow or very slow
 
I also feel that it is not unusual for a slight delay of a few seconds before seeing oil pressure on the pressure gauge. Both my 2N and 8N have a couple of seconds delay.

But 15 seconds does seem like a little too long. Are you sure that it takes that long? Sitting on the seat watching that gauge can seem like an eternity.

You may want to consider using the lower viscosity oil during winter time, as TOH suggests. I also use Rotella 15W40 in my tractors, but they don't see much winter use. I would use 10W30 if they did, and put the heavier weight oil in during their spring servicing.

Colin, MN
 
Thanks so much for all the advise! I will check the gauge and think I will try using 10W-30 oil and see how that does.
 
My '48 also uses Shell Rotella 15W-40. I don't know it's history but it's a strong runner.
When I first start it my gauge comes up almost immediately. In the winter it'll max out at about 35 lbs. of oil pressure. Fully warmed up it'll show 12-15 at idle.
 

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