Farmall Cub

i have oil seepage out of the head gasket on my 1947 farmall cub,its a slow leak. today i purchased a new head gasket on ebay for $26, about 1/2 dealer price. anyways i was wondering why my tractor does this. i didnt believe there is any oil flow into the head. tractor does not burn oil. i just want someone to explain to me why this is on a flat head engine? i didnt think it was possible, its not like an overhead valve engine that has a valvetrain in the head, all valves, rockers, and springs in the block

most likely it is not the head gasket. the oil seal for the oil filter will leak and oil will "run" the head gasket. Make sure that is not the cause before you pull the head.

Napa can get you the same gasket for about $14

didnt know that napa could get that gasket so cheap, i try to avoid napa; too many junk car parts. i drive older cars and do my own repairs. i have generally found napa prices to be outrageous any typically their quality sucks. however i could see buying a head gasket from them; no mechanical or moving parts. i cannot believe that the case/IH dealer sells them at $50. i also didnt think napa was in the business of selling tractor parts.

as far as the oil filter unit, i replaced the lid becuase i had the aluminum lid (bought a steel) AND i have a new gasket installed. it was leaking but that should have cured the leak. is there anything else i can do to prevent leaks around the oil filter chamber. i do think i know why they no longer use a chambered oil filter and why they are all spin on now.

i still think it needs a head gasket since i did work to the oil filter chamber, its it possible oil is leaking from the head or is it a physical impossibility on an engine that does not smoke and has clean good looking spark plugs. i removed a couple plugs and there is no sign of oil burning at all, a good healthy engine.

should i power wash that side of the engine and see if its just old oil?

if not the head gasket i would save the head gasket for future repairs; if it is the head gasket i have one on the way

If the oil cap is put on too tight it will warp and leak. Also make sure the gasket is positioned right. It is unlikely you are seeing the oil coming from the head gasket. Removing the head on a Cub can lead to some big headaches if any of the bolts break.

Breaking a head bolt can lead to this,


And this,


And even this.


It isn't worth the effort to remove a Cub head unless absolutely necessary.

By the way, NAPA has been selling many tractor parts for years. They are usually my parts dealer of choice. However, you could have bought a good gasket from TM Tractor Parts, one of the forum sponsors, for $22.00. They are great folks to deal with.

The only way to get oil on the head is through the rings. If it was coming through the rings in that quantity, it would also smoke.

Is your seepage enough to cause drops to hit the floor?

If your leak isn't drastic enough to be noticed on the stick and there is not enough volume to make it to the floor, as previously posted, sound advice is to do nothing at all. If the head is actually leaking oil is may well be from the piston rings but in a slight quanity causing no visible smoke.

When chasing any oil leak, a thorough degreasing is mandatory if you wish to determine the exact point, cause, and volume of the leak.

Before spending time and money pulling the head, clean it up like new and keep an eye on it for a few months. The gasket can certainly be used down the road.

lazyuniondriver wrote: If the head is actually leaking oil is may well be from the piston rings but in a slight quanity causing no visible smoke.

It is hard to me to understand how a slight quanity of oil could come by the rings and make it through the head gasket to the outside without also having coolant seeping out. Yet no smoke blue or white.

Barnyard wrote:If the oil cap is put on too tight it will warp and leak. Also make sure the gasket is positioned right. It is unlikely you are seeing the oil coming from the head gasket. Removing the head on a Cub can lead to some big headaches if any of the bolts break.

Breaking a head bolt can lead to this,


And this,


And even this.


It isn't worth the effort to remove a Cub head unless absolutely necessary.

By the way, NAPA has been selling many tractor parts for years. They are usually my parts dealer of choice. However, you could have bought a good gasket from TM Tractor Parts, one of the forum sponsors, for $22.00. They are great folks to deal with.

good grief i didnt realize they could be that bad. i have removed heads from a ton of 40 year old kohlers and i have never broken a bolt i have removed heads off of 25 year old chevys as well and i have never broken a bolt. was the tractor that engine came off of a tractor that sat outside too many years, was the rest of the tractor badly rusted? if the head bolts were exposed in the rain for 50 years i guess i could understand why it was an issue. still i have removed heads from kohler k series that sat outside for 20-30 years and i didnt have a problem.

No it probably won't be that bad but the worst case scenario was brought to light so as you stand over the block, cutting torch in one hand, big hammer in the other, you could not blame anyone for not telling you it was probably a bad idea to fix something that wasn't that broke.

The head bolts on the cub extend into the water jacket and rust. Others develope carbon buildup between the top of the block and the bottom of the bolt head, causing the bolt to break off IN the head, leaving part of the bolt in the block.

wellsknob wrote:It is hard to me to understand how a slight quanity of oil could come by the rings and make it through the head gasket to the outside without also having coolant seeping out. Yet no smoke blue or white.

Compression tests, dry then wet before pulling the head.

Talking about opening up a can of worms....

No oil passages are contained in the head on a Cub - only water.
All the oil passages are in the block.

I also had one of those broken head bolts and was reliving the horror of trying to get the broken one drilled out without destroying the block as I looked at the photos. Took lots of patience and prayer to get it out. That particular bolt had corrosion in the shank above the threads which weakened the bolt. There was a water leak in the head directly above that one bolt.

As far as parts...if the gasket says Fel-Pro on it, it doesn't matter where you get it from. I play Napa against OReilly against Rockauto and go with the lowest total cost for the identical part. Sometimes the dealer beats them all....