Farmall Cub

As you can tell by the user name, this is my first Cub. I have read the procedures on lubing and 3rd gear and have been doing it a few times a day since Tuesday. My main concern is about the piston locations. It seems that all 4 pistons are very close to the same position from the top of the head/spark plug holes. They are all roughly 1 inch from the top of the spark plug holes. That just seems odd to me.

Obliviously I can't spin the motor to see the stroke or how they work. Does this sound correct, or should I go a head and pull the pan and check the mains ? Thanks in advance.

Pistons 1 and 4 should be in the same position. Pistons 2 and 3 should be in the same (some other) position. 1 and 4 travel the opposite direction of 2 and 3. So the only place they will all be the same is at 1/2 way in their travel. Stroke is 2 3/4 inches. So they will all be in the same place at 1 3/8 from the top.

Hi,
If you are reaching in through the spark plug holes to feel the pistons, with a screwdriver, or something, the pistons are not straight below the spark plug holes. You might be hitting the block, and the valve areas, if you are reaching straight in.
The pistons are to the right side of the engine from the spark plug holes.
Angle the screwdriver to the right and it should go down into the cylinders, if some of the pistons are down.
Below are pics from TM Tractor of the engine block, and head. You can see where things are under where the spark plug holes would be, if the head was on the engine.
There are 3 rows of head bolts, front to rear. The spark plug holes are between the left and center rows of head bolts.

I have been in the same place that you are in. Pull the pan and unbolt the rods one at a time. In my case I only had one piston stuck in its bore. (Assuming you already have the head off. If not you will surely want to pull it)
Here’s hoping you get as lucky as I did...the rod and main bearings were fine with just one stuck piston.
Something new to me, but probably not unique to Cubs was the ring end gap. My tired old tractor had 0.120 end gap when the spec is in the 0.020 range...(0.012 to 0.017) shows how much wear they had.
Good luck with your journey...many of us have taken a similar path.

Thanks for the replies and info guys, I definitely do not feel like I am totally in the dark now. I will jump in with a fresh start/mind in the morning. I will update. Thanks again for the help !

Glen, I think you just helped my broken heart ! I now see/feel what you are talking about, and with Jim and the others info....I think I am fine. Cyl 1 and 4 and 2 and 3 are good. I will sleep better !

make sure that it not just the valves are stuck before tearing in to the engine

tst wrote:make sure that it not just the valves are stuck before tearing in to the engine

And check the starter and fan.

I would keep trying the lub too. It took me 4-5 weeks of penetrating oil in the spark plug hole and rocking the rear wheels before I got a block to loosen up

Start with easy before you pull the head and pan.

inairam wrote:

tst wrote:make sure that it not just the valves are stuck before tearing in to the engine

And check the starter and fan. Start with easy before you pull the head and pan.

Before you pull the pan and head, remove the panel under the intake/exhaust manifold.

You should be able to lift any unstuck valves with a screwdriver since it only takes 26 lbs. to compress a Cub valve spring.

I have already removed the starter (Tuesday when I got it) and the fan is free. I am going to get some more oils and apply more directly to the top of the pistons now that I see the sweet spot. I will give it more time this way before I remove the valve cover.I can see several open valves. Thanks again.

Here is a pic of my project.

Going through the same steps on my new to me. Keep us posted. All this information is great

XRCR, sill no progress. Now that I feel good about piston positions, and just waiting I cleaned the inside of the tank(which was actually not in bad shape) and installed a new settlement bowl asm. I have cleaned the carb (IH) and made sure the float didn't leak and just need to set/adjust it. I also saw how the carb body warps and mine was indeed warped. I have it straightened out. I dropped the starter off yesterday at the local starter/alternator shop to see if it can be fixed at a reasonable cost. I am going to go a head and make a new fuel line as one of the nuts on mine is worn out and almost round.

I am just trying to get it ready for starting if the engine finally breaks loose. I am not going too deep with other stuff until I see where I am with the engine and compression etc. I am not a real patient person so trying to break this engine loose is wearing on me. It was a week this past Tuesday. I will give it some more time and then probably remove the valve cover.

Thankful for this site and the helpful people for sure. There has been nothing so far I haven't been able to search and find answers to. Keep me posted on your journey as well !

Did you check/change the engine oil?
What did the oil look like that was originally in it?
If it was contaminated with water, the bottom end may be corroded and contributing to the lock up.

FIRSTCUB wrote:I am not a real patient person so trying to break this engine loose is wearing on me. It was a week this past Tuesday. I will give it some more time and then probably remove the valve cover.

Patience. Patience. Patience. Give the engine time to break loose.

Spray solvent under the open valves. Try to get the spray on the valve stems. Cub engines have a tendency to stick valves if they set for very long.

Story. My Grandfather's WC Allis Chalmers had a stuck motor. I worked on breaking the pistons loose for 6 months. Never did get the engine free. Bought another WC with free engine. Gave the stuck engine to a family friend who owned a WC. We placed the engine in a 55 gallon drum and the new stuck engine owner filled the drum with waste oil.