50A rebuild

So I had a piston skirt break. I found a different set of standard bore pistons. But when I got them they were an inch taller than what the tractor had in it. The person said they were from a square axle A. Will the taller ones work?

Depends on where the difference is.

If the distance from the center of the pin to the top is the same, and the crank doesn't hit the bottom of the skirt, maybe...

But an inch is a lot! Very doubtful they will work.

Usually, an engine (or the liners) is custom bored to fit the pistons. Even though standard bore, best check the clearance before assuming they will fit.

Do you have an email I can sent some pictures to?

A few more posts and you can put a picture on here. Are the pistons notched for the spark plugs in some fashion?

An inch taller how, overall or pin to crown? I would assume a piston from a square axel would work in a 1950. Was your tractor an All Fuel tractor? Did your tractor have stock pistons. I had a friend who ordered a single replacement piston for a Continental 176, the only piston he could get had a dome and he was concerned it wouldn't work with the other flat top pistons. It was just a solid dome so I just milled it flat.

An inch isnt a lot more, its a WHOLE lot more. Deere came out with the square axle in 1950 so you are in the right time frame. I am not familiar with the height difference between all fuel pistons and gas pistons butI doubt if there is a whole inch difference between the two.

Is the pistons that were in the tractor that the one broke a cast steel and is the one you got aluminm? I am guessing that the one that broke is a cast piston for an all fuel tractor as the all fuel is a very low compresion and for a gas tractor the pistons are taller for more compression and higher horsepower. Then the aluminm pistons are for higher compression yet and are aftermarket. If what you got is the aluminm I would try to get the mate to it and instal them IF the diameter is correct as you have to figure out if the block has been rebored and if it has is it 45 over,90 over and that is all Deere made for that tractor but the after market aluminm pistons could also be 125 over size. So first thing is was the block ever bored, they do not use sleves. Then if overboard is it the 45, 90 or 125? And then is it an all fuell tractor or a gas tractor. If either an all fuel or a gas those taller pistons will work IF the diameter is correct But the pistons do have to be replaced in pares if different than what you took out. I had both a 49 B and a 51 A both gas tractors and they were rebored but I forget the exact size over bore but at that time the B was reboard Deere did not make a piston large enough for the over bore so all was left to do was the aftermarket extra high compression pistons. Without checking my parts books I am sure the crank is the same for either gas or all fuel as stroke is the same on both. Just different piston height. The all fuell tractor had a 29 PTO HP, the Gas 38 PTO HP and the higher compression aftermarket aluminum pistons were never tested at the test site but I am guessing they would put the power to around 45PTO HP. Sleves could be had but rare to install in a block that was totally dammaged beyond the oversize pistons but not done unless a replacement block could not be found. But then there is the POWER BLOCK option that was entirely different on piston size being if I remember correctly a half inch bigger in diameter and also still a higher compression. Your 1950 A could have been a gas tractor but still have had the extra fuel tank like a all fuel tractor. The 51 only had one tank and it was larger that the tractors with the 2 tanks.

It appears from the picture that all of height is between the crown and the pin. I would only install those pistons as a set. why not at this point just install them and see how they look. Check to see if they leave the spark plug uncovered and that the oil ring doesn't extend out of cylinder rear. Unless the tractor is being used for heavy drawbar work a little extra compression will not be an issue.

Yes our 50A has a smaller tank as well. Dad said he alerted just ran gas in it. The piston that broke was cast. The new/used ones are not aftermarket. They are out of a square axle A also. They are the correct diameter just taller. Im all about making more HP just dont want to scatter the engine in the process.

I see the grove to uncover the sparkplug, make sure you get that positioned correctly.

The piston with the notch looks like it came out of a 60 or 620. what is the casting number inside the skirt?

I've got some pistons like those with the notch in a Unstyled A.

Yes

Sounds like your tractor was an all fuel and the ones you got were from a gas tractor. So luckey if they are correct size. And don't wory about too much compression as pullers put in pistons to get way more compression that the aftermarket aluminm ones. As long as they can be gotten inyou will not hurt the engine and you will like the more power. I used mine for years with the higher compression aluminm pistons for all the farm work as they were the big tractors.

Awesome. Its a big nut G carburetor. So Im excited to see the HP increase and compression increase. I have a 51A thats at 110psi and a 47B thats at 120psi

looks to me the differance is an all fuel piston and a gas piston.