Is M oil pump same as 450 diesel?

jhncp

Member
Will it work to try an oil pump from an M on a 450 diesel? The 450 has an aftermarket oil pressure Gage and it's barely past idle mark when warm. Also if I unscrew Gage the line just has a slow drip, is this normal? I don't know if it's possible line could be plugged. I put new rod bearings in but don't want to do mains if it can be avoided.
 
M diesel yes, M no. oil pressure lines should be flowing more than a drip. I would put a good pressure gauge at the block (adapt as needed) to get the full story. I assume you are looking at the oil pressure in the hood opening, and not the pressure on the fuel injection pump. Jim
 
You will get a lot more than a drip if the oil line is unhooked and you have good oil pressure.. I know from experience in forgetting to hook one up to the gauge.
 
Yes the engine oil pressure at the dash. I also have a problem with compression leaking into coolant and prably antifreeze leaking in cyl. #1. I just put new head gasket on. Is it possible head could be cracked? I tested with valves closed. I plan on buying a inspection camera I hopefully can fit thru injection hole.
 
Machining the head requires setting valve recession so the clearance and compression are maintained. They do crack if not shut down after idling on diesel far 5 min if worked hard, or at least 3 if warm. (no matter what others say) and then shutting off, leaving in diesel mode. The head oil passage is at the very front of the block on the right side of the front of the head. Jim
 
Drop the pan and see what's going on in there. I've taken apart more than one M size farmall that had significant blockage of the pump pickup screen. Also have fixed a couple of pumps by making a new pump shaft; the pump shafts were worn pretty bad where they turned inside the pump casting. Casting was otherwise fine. Check pump gear end clearance as well.
 
First off, very little oil comes through those long tiny lines to the oil pressure gauge so that isn't going to tell you very much. You have to put a gauge right in the oil gallery to get a good reading. Also, a Diesel has much less oil pressure than a gas tractor. Like 45 psi where gas is close to 70 psi so make sure you have the correct gauge for your tractor.

Oil pumps do wear out badly and cause low pressure and also the regulator valve is in the oil filter base on the diesel model tractors, not in oil pump. Might want to check that also.

As for leaking coolant, well, I am afraid you know head will have to come off if you know it is leaking into cylinder. A inspection light will be very difficult to show you much through the injection hole as it is pretty small under that precup. Make you you have proper head gasket also as there is often times a mixup on gaskets on those engines.

If you have pitting in head or on piston you know it has been leaking. Cracks usually are pretty easy to see on those heads but not always.
 
Thanks for the info. I do recall you are correct the diesels are suppose to have less oil psi than gas. I am confused about why, you would think a diesel should have more?
 
I think I will want to at least try the inspection camera to see if I can pin point an antifreeze drop otherwise I'll go thru all the work taking the head off for the third time and won't even be able to tell what the problem is.
 
I never had the luxury of having a inspection scope while with dealership. Bought a cheap one a few years ago but pretty much useless. I did a lot of pressure testing of individual cylinders. I like that test to see if there is leakage, which cylinder it is in and also detect leaking rings, valves etc. Takes time to do it of course.

As for oil pressure, I don't know what the engineers reasons were but that engine has huge crankshaft and bearings and a lot of them for the cubic inch of engine. My old Chev was 14 psi, but with the dipper on the rod picking up the stream of oil directed at it from the tubes in oil pan , who knows how much pressure that rod bearing was absorbing.
 
Those engines have a huge amount of iron in the bottom end for the amount of power they put out. My guess is they didn't need as much oil pressure with so much bearing surface area spreading out the force.

Engineering desicion. You need enough pressure to push enough volume to the furthest point in the system. Any pressure beyond that and you're wasting energy and heating oil from bypassing it through the pressure regulator. The pressure gets the oil to the bearings but after that you need a combination of proper bearing clearance and oil weight and volume for the hydro-dynamic wedging action to occur. High oil pressure won't save a bottom end that's worn out or built too loose.
 
I put a air nozzle in injection hole #1 cyl. With valve closed and it's easily bubbling in radiater. If I don't know where it's leaking before I pull head off I dont know how to test head with it off or prably won't be able to tell the area of head gasket leaking.
 
This tractor also has oil thru rods so I would want to be sure there's adequite pressure for that. I don't know if the rings rely on oil from the oil running down from the oil thru rods.
 
????????? My I-H service manual says the diesels are rated at 70 lbs oil pressure just like the gas Ms.

I think what you are thinking of is the As-Bs-Cs, which have lower (45 lb.) oil pressure. That is where the 45 lb. oil gauges are supposed to be used, not on the diesels.

Brian
 
Your manual is wrong. Worked on many of those diesel engines. We sold new 450 Farmalls we had just before the 560 came out.
 
True. But if you can get a scope in there and take a look, let us know how that worked. No experience with good scopes.
 
The I-H service manual is wrong. Really??????????? Then why does the parts book call out the SAME oil pressure gauge for both the M and MD? 41934db.

Go look it up in the parts manual and see for yourself. I'll wait :)

My MD has a 70 lb. gauge and it has always run over 3/4 of the way to the right.

Brian
 
Don't know what book you are looking in. Just checked original paper parts manual for a super m and super md. List a 75 psi gauge for super m gas 41934 DB and a 45 psi gauge for super m diesel 258634 R91. Those online catalogs has a lot of Case updated parts and they tend to label parts pretty weird sometimes. I made my living working on those tractors for many years. Didn't own any.
Replaced the gauge on a 450 Diesel a few years ago as it had the wrong gauge. It had the 75 psi gauge.
 
Out of a 450 D operators manual.
cvphoto42346.jpg
 
Looks you were right, the inspection camera was prably a big waste of money. I had another idea. If I put antifreeze in at certain levels in head, like 1/8" increments above head gasket, and keep testing with air pressure in injection opening, and listen for bubbling, will this help me dtermine if it's the head gasket or cracked head? Perhaps if the head is cracked it will need to be at a high level to bubble?
 
Heads can be assessed for cracks easily at the rebuilding end of the process. Flatness of the head surface, valve recession. and even the texture of the head can make a difference in keeping the gasket in tact for operation. I make sure the small oiling passage has an Oring (not standard to be there, and requires machining a counter bore for it) as they leak there. If it bubbles now, it just needs to be pulled. Jim
 
I assume you mean the gas side of the head? How big is this plug and can u test pressure there as well? Also what are the 4 pipe plugs for near the bottom of head on diesel side? Of course I couldnt get one out so I drill it out and noticed I drilled into a brass piece behind pipe plug.
 
Not an external port, but the passage from block to head for valve train oil. They can leak there and make a mess. Jim
 

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