Farmall Cub

I want to rebuild my cub engine what is the max hp I can get out of it? What do I have to do to get it?

93gman wrote:I want to rebuild my cub engine what is the max hp I can get out of it? What do I have to do to get it?

Practical and least expensive thing to do is just to return the engine to it's factory condition.

Need to know which Cub engine you have. Some engines put out 18 horse power while other about 13 horse power. If you have one of the earlier engines and the block needs bored, you could install domed pistons and change the cam and a couple of other items.

The major difference, besides the parts, is that the higher hp engines operate at higher RPMs.

Edit:

93gman wrote:I want to rebuild my cub engine what is the max hp I can get out of it?

As a wild guess, 60 cubic inches times 4 = 240 horse power.

Eugene, according to that calulcation you'd have roughly 100 more HP than the 1468 and thats an 8cylinder diesel


Horsepower is torque x RPM divided-by 5252

Not to rain on your parade gman, but if you're looking for more horsepower you're better off with a Super A.

A little background maybe a good idea. The engine that is in it is very tired. I just want to mow grass with it. But when I let the grass get to about 6 to 7 inches the tractor has a hard time when going up a little hill. And I mean little. It does a fine job when it goes down the slope. I also love the tractor.

Is 60 over to much?

Then maybe the problem is as simple as the governor not kicking in. When you start the incline the rpms should increase if the governor is kicking in.

I don't have a gauge for the rpm. Should I just be able to hear the increase

Yes, the increase should be noticeable. If it is not it will seem totally underpowered. What size of mower do you have on it. Is it blowing smoke? Cubs should mow pretty easy except for tall thick grass.
Oh, and welcome to the forum.

Start out with a complete engine tune up including compression tests. This will provide information on the engine's condition. If the engine has not been completely tuned up in a while, the tune up will show an increase in engine performance.

If the engine needs rebuilt, bringing it back to specifications will provide a significant improvement in the tractors performance.

93gman wrote:Is 60 over to much?

.060 bore is right at the maximum for the Cub engine.

havoc1482 wrote:Eugene, according to that calulcation you'd have roughly 100 more HP than the 1468 and thats an 8cylinder diesel Horsepower is torque x RPM divided-by 5252

While I really don't know if the C-60 is capable of being reworked to obtain 240 Horse Power, it is capable of quite a bit more horse power than the factory engine. Again, the major change in increasing horse power is in the RPMs.

Some folks confuse horse power with torque. For a farm tractor, torque at a reasonable RPM is more important than potential horse power. The peak torque of the C-60 engine is around 1600 RPMs.

So are you saying increasing the hp beyond a certain point is wasting hp and money? If so what is that point? Is there a place that you folks buy parts from?

the engine does smoke and uses oil. I don't know if you want to get into the story behind the engine. basically the tractor was pulled out of a field that it sat in for years with out running. I changed the oil, spark plugs, wires and fired it up.

The bottom line is that the engine will still be a 60+/- cubic inch, low compression, carbureted, four cylinder engine. You can expend a lot of blood and treasure getting an extra 10 or 15 percent out of the engine, but to what end? A properly tuned Cub engine, in good factory condition will mow all day long without any issues.

Re: mowing. Cannot stress enough "Aditude or angle of attack". When cutting height is set, mower must be slightly lower in front. Do whatever it takes within reason. Mowing flat or high in front takes 2-3 times more power. Do a search for other thread on this subject .
Also search "angle of attack". Welcome to the forum!

Go ahead and finish the complete engine tune up.

Try some SeaFoam in the fuel and engine oil. See if this frees up the piston rings.

I obtain most Cub parts from the local auto parts stores. Other parts from the Case/IH dealer and from advertisers on this board.

Search this site for horse power and torque curve for the C-60 engine.

As Don states, you can spend a ton of money upgrading the engine and obtain an additional 2 horse power.

93gman wrote:...I don't know if you want to get into the story behind the engine. basically the tractor was pulled out of a field that it sat in for years with out running. I changed the oil, spark plugs, wires and fired it up.

That is exactly the kind of information we need. I suggest following Eugene's advice and do a complete tune-up with dry and wet compression tests. Then you'll know what you're dealing with. Running some Seafoam through the gas tank and the oil is also a must for tractors that have been sitting for a while.

Welcome to the forum!! If you're able to post some pictures of your Cub, we'd like to see it.

First thing you have to remember that most cubs out there are 1/2 worn out. C-60 engines only made 9 HP from 1947 to around 1963. THen depending on the internals of the engine from the factory they may have made 12 HP. Never heard of one with 18HP!! A farmall cub with good engine will run a 59" woods in 8 inches of grass with no problem. Now what I do when rebuilding a c-60 is use aluminum pistons and a electronic igniton in my own cubs. I dont think it increases engine HP but Ibeleive it increases torque from not having to push such heavy pistons. NOw I have souped a cub engine up years ago. it was pushing over 20 HP but that was at 3200 rpm and the cost of doing so is not worth it.