Farmall H oil use

Hello,

I am helping a friend work on a 1950 Farmall H & we are having a problem with oil blowing out of the exhaust. We did a compression check (Better than 100 PSI across all cylinders with little difference between them), a leakdown test, measured the cylinders with telescoping gauges/mic's (All W/I .002 of factory spec, top & bottom), & adjusted the valves. It blows quite a bit of oil out of the exhaust, it seems to do this whether hot or cold. Another friend thinks this is a ring problem but I'm not sold on that. Could it be worn valve guides & what is involved with repairing that?

Also, we have the manuals for it, but are there more detailed manuals available? Maybe with electrical schematics?

I may be totally off & would appreciate any help,

John

If it is valve guides it should seem to get marginally better
when it gets worked hard. When the head heats up it will close
that gap just a little.

Your best bet is to pull the head. You can tell what the sleeves
look like and if all is well take the head in. It wouldn't surprise
me if the head needed work. It seems like the engines got
rebuilt and the heads just got slapped back on years ago. The
last M head I had done was about $500 but there were
multiple cracks to fix, seats, etc. - it was a bad case.

Has this tractor sat a while? Was it one that was previously stuck and then freed up? If yes, rust in the cylinders could have damaged the oil rings or you might get lucky and they are only stuck.

After verify the airbox is not restricted, the little pipe that runs to the airbox is not restricted, any engine vents are not restricted. Most importantantly check that little pipe that runs from the front of the head to the governor top and make sure it is present, not kinked, flowing, and not restricted with crud.

If you find nothing, then I would pull the plugs, add some ATF to each cylinder. Let it sit a day or 2. Add some ATF or Marvel Mystery Oil in a reasonably strong concentration to the gas. Then hook it to an implement and work the snot of it and hope the oil rings free up.

Farmall h's do not have oil seals on the valve stems so they can pull a little oil there if the guides get worn but they would have to be worn real bad to cause what you describing unless that little pipe that I mentioned earlier from the head to the governor is not draining away the excess oil from the top of the head. Then even a head in good shape but without valve seals would pull excess oil in around the guides simply cause there is excess oil there not draining away

Temp fix would be to add umbrella style valve seals to the valve stems using an air chuck or careful rope and piston placement to hold the valve in place without removing the head. Course if the guides are worn really bad this will only be a short term fix but it would let you know it is indeed the problem.

If it ends up being in the valve guides then pulling the head and having a machine shop press in new valve guides would be the best fix. Machine shop Knurling the old guides back to spec would be a compromise fix but remember knurled repairs last half as long as new guides would. Course doing either of these necessitates doing a valve job and you might as well add new umbrella seals as an upgrade when all this is done too.

Start with the simple no cost stuff first.

Worn valve guides will allow oil to seep down into the cylinders while the engine is not running, and naturally that oil will be burned off when the engine is started, so there WILL be some blue oil smoke coming out the exhaust when the engine is first started, but that will usually clear up after just a minute or two.

The ONLY time I have witnessed actual oil being blown out the exhaust is when somebody mistakenly over-filled the crankcase with TOO much oil. An H holds just 6 quarts of oil. If you poured in 8 quarts, some of it will blow out the exhaust.

The owners manual has a very good wiring schematic.

2 things, if it is drops at start p, it may be water that condenses in the exhaust being mixed with the normal soot coming out and landing on the hood. That is common for tractors that are stored where it is cold.

Another thing to think about is that if the rings are bad enough, they will oil seal, and show good compression at cranking speed, but be low on power and have a lot of blowby when running. This only happens if they are REALLY bad and maybe broken though.

You talking about blue smoke or oily soot on the hood and gas tank. If I go out today (7 degrees) and start my Super C and Super M both of them will be shooting black slimy soot on the hoods, condensation.

I'd have the valves done and racing seals put on
that takes care of the oil going down the guides.

Just to be sure we are on the same page, the motor
is blowing liquid oil the exhaust when it is
warmed up ? Or is it smoking ?

If it is liquid, it would have to be coming from
the exhaust guides. Unless the oil is really
running out it should evaporate and smoke when the
manifold is hot. You can tell if it is just wet
soot by letting the spots dry.

How much oil does the engine use ? What was the
difference between wet and dry compression tests ?
What is coming out the breather on the side of the
engine ?

Greg