67 3400 3cyl gasoline - oil pressure issue - pump?

Jim 67 3400

New User
Over the winter I got some rain and or snow in the cylinders and crank case I have since drained it out flushed with fresh oil drained that, I put more fresh oil in but I am having trouble getting the oil pressure light to go off. I modified a spin on filter to plug the oil supply to the engine and blue compressed air through the new clean filter to try to blow out the oil pump if sludge got in there but that hasn?t worked either. I really don?t want to have to drop the oil pan and pull half the tractor apart is there something I can do to the oil pump to manually spin it? There is an oil drive gear cover that accesses the oil drive maybe I can pull that gear and ride out and spend the oil pump manually?
Thank you in advance for your help look forward to hearing from someone!
Jim
 
Pull the oil pressure sender switch and put on a mechanical gauge to see what the pressure really is.

The sender switch a normally open switch and when the oil pressure builds it closes the contacts and completes the circuit to ground. It could just not be making a good ground connection or the switch itself could have gone bad.
 
Get at least a 100# gauge. I just bought a 3910 which is the same 3 cyl engine with about 20 more cu in otherwise pretty much the same engine. The idle
oil pressure, with 15w-40, 75 degree F startup at 1000 rpms is 55#. I haven't measured my 3000 but I have a 4 cyl 2000 and it too reads up in the 55# area
so I guess Ford runs a high pressure pump.

The idiot lights I have tested run around 8-10# to go out. With that said and if your sensing circuit was accurate, your engine would be starving for oil and
you would hear it talking to you......mechanical rattles.

You may have gotten some crud in your oil pressure pickup, blocking the input to the pressure switch.
 

Pull the filter off and crank the engine with the fuel stop out.
If it doesn't pump oil out of the filter base pull the oil pan and find the problem.
If it pumps oil out of the filter base install the filter, then remove the oil pressure switch and connect a mechanical gauge.
Start the engine and see how much oil pressure you have, if it's below 10 psi shut the engine down and pull the oil pan off to find the problem.
Oil pressure below 20 psi hot indicates ether a worn engine or problems in the oiling system, pump, screen, drive, ect.

The freshly rebuilt engine on my 4000SU will make 75 psi oil pressure and maintain 40-45 hot.

If you have to remove the oil pan use a floor jack under it, those cast pans are heavy.

Sean, the oil pressure switch is normally closed completing the ground circuit to laminate the light, oil pressure opens the circuit eliminating the ground.
 
Thanks for the replies! I should have been more clear; I did crank the engine with no coil wire, and nothing came out of the oil filter base (filter
removed). Can I pull the gear cover then the drive gear and manually spin the pump? What are the moving parts that could be broken? Any tips
on unbolt I NG the front axle to access the front pan bolts? I do have repop manuals and I?m hoping I don?t have to go there but I get the feeling
that that?s what I gotta do.
 
Sean, the oil pressure switch is normally closed completing the ground circuit to laminate the light, oil pressure opens the circuit eliminating the ground.

Sorry, I claim lack of sleep as the reason I totally screwed up on that one. :D

My mother-in-law next door had her roof start leaking Friday evening during a storm, and then her septic backed up into her basement on Saturday, so I've been going non-stop trying to keep the water out of both ends of her house.

Start the engine and see how much oil pressure you have, if it's below 10 psi shut the engine down and pull the oil pan off to find the problem.
Oil pressure below 20 psi hot indicates ether a worn engine or problems in the oiling system, pump, screen, drive, ect.

So what pressure do those switches normally open up at? I thought it was something pretty low, like 5 or 7 psi. If anything below 20 psi is bad, then lots of folks are probably running in the danger zone without realizing it.
 
They're called "idiot lights" for a reason. All they're really good for is to alert your typical brain-dead operator that there's a big
problem that requires immediate attention. That said, you're right, that light is not coming on at 20 PSI. If an engine really has 20 PSI at
working speeds, the bearings and crankshaft will be not long for this world.

On the other hand, 20 PSI at idle is just fine. If Ford (or any other mfg) set the light to come on at 20 PSI, everyone would be ignoring it
because it would always come on at hot idle.
 
Thanks for the replies! I should have been more clear; I did crank the engine with no coil wire, and nothing came out of the oil filter base (filter removed). Can I pull the gear cover then the drive gear and manually spin the pump? What are the moving parts that could be broken? Any tips on unbolt I NG the front axle to access the front pan bolts? I do have repop manuals and I?m hoping I don?t have to go there but I get the feeling that that?s what I gotta do.

I already know there?s no pressure, I got compressed air to bubble through the oil pump into the pan, hoping that it was just sludge clogged but still nothing. My next thought is to pull that pump gear cover and gear, maybe there is something broken in there? Any further thoughts along those lines?
Thanks
 

I have heard of the hex shaft rounding over where the gear doesn't turn the pump.
You can remove the plug and pull the cam drive gear, but beyond that the oil pan has to come off.
 
Pump drive goes in with the pump, cannot be dropped in from above. Go ahead, ask me how I know. :(

I say order a gasket and drop that pan, anything else is unproductive guess work.
 
I just replaced my pump last week. It’s as easy as dropping the pan and removing 2 bolts. After 40 years I figured it was worth the little bit of money the throw a new one on.
 

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