what weight motor oil in my 1956 ford 800

have low oil pressure in my ford 800 ----have been using 10w 30 . should I go up to 30 or 40 weight. have no engine noise.

Recommended oil weight varies by location/climate.
If you're in a warm climate, heavier oil may work fine.
I'm in Michigan and I can get away with running 15W-40 year around.
Even then, I'm not real comfortable with cold startups sometimes.

Bear in mind that heavier oil to fix oil pressure is a band-aide.
Oil pressure is a function of bearing clearances.
Low oil pressure means worn bearings somewhere.

WESSON??? MAZOLA??? ; > ) Low oil pressure is a sign of a worn engine. Some fellas turn the oil relief nut (48-6666) in to increase spring tension in hopes of increasing oil pressure, but that and/or switching oil grades are only temporary band-aid fixes if they work at all. These FORD's are tough SOB's. Back in the days, farmers would run them on whatever was available, including recycled/used motor oil. Heck I did too when my '48 8N was in need of an engine rebuild. I saved my oil from my F-250 at oil changes and put it in the 8N as I had to work it several hours a day once a week. Oil pressure would be down to 5 PSI at idle after a few hours or less of work. I didn't run it for very long like that, rebuilt the engine and systems.

Tim *PloughNman* Daley(MI)

In Texas back when that tractor was built, 20w was winter oil and 30w was summer oil. Multi viscosity today is much better than when it came out in
terms of meeting the 30W part of the spec at the higher engine temperatures.

Many oil companies are offering "old engine" multiviscosity oil which you might try....ww carries it.

I have a '63 2000D with 3800 original hours that was blowing blue smoke. The oil would turn black within an hour or two after changing. Upon draining
one day I checked the bottom of the oil pan and it had a layer of sludge even though I have had the tractor for over 20 years and change the oil regularly,
using 15w-40. I was already using Power Services "snake oils" in the diesel, but decided to ad Sea Foam snake oil to the oil a few hours before changing
the oil. I have used SF in the oil in 2 cycle outboard motors and it worked in loosening the rings from the caked carbon that builds up and makes you
think you need new rings when you don't.

After a couple sessions of that and on the last instance, draining the oil (carefully since the oil is hot) right after a hard run, and refilling, three things
happened: The sludge disappeared, smoke all but cleared up, and the oil stayed pretty clear after a few days of hard running.

Worth a try . Nothing ventured, nothing gained....or lost.

On several occasions I have put in a Quart(or more in a dirty engine) of diesel in the oil just before a change to clean. Only idle for 10 min or so.Works.Doesn,t hurt a thing. I recently bought a Farmall 400 that was FILTHY beyond belief. I gave it 3 'treatments, to clean it out.I actually removed the oil filter so it would not plug up.The old tractor is clean inside now,runs better too.

What do you consider low?

Is the oil pressure gauge good? I've seen an old gauge show 5-10psi off.

While good red tigers can kick op out in the high 50's range when tight, even old workers that rattle on at 20psi are fine. If I see a minimum of 6 psi per 1000 rpm, I don't worry too much.

I have a beater 950 Frankenstein. I run 15w40 oil, she starts at 40 psi and after hours of work, she is 20-22 at hot throttle, and 15-18 at hot idle.

Worn for sure, but not worn out...yet. 15-18 psi , hot, at 500 rpm still keeps everything rolling just fine.

Ps, I use 15w40 in almost all my tractors, gas or diesel. I have 2 rare exceptions that I've done head/valve work on, and went in with 10w30 synthetic on a clean engine. More of an experiment than anything.

Been using 15W-40 for several years with no problems.