Are all horses the same size?

Down on my Mom's farm is an old Farmall H with a locked up engine. We had several of them over the years and this one would have been used for parts except my dad never got to it, so it's pretty complete.

I've been planning on repowering it with a TBI Iron Duke, since it is pretty much a tractor engine and I have one in the barn. The real hold up on the deal is finding a governor for it.

Enter Harbor Freight with a brand new 22hp engine for $700.

Now the H was never 22hp, more like 18-21 based on fuel and tune. Sure it's @150ci, but it was built with a compression ratio in the 5's and a top rpm of under 2k. The HF v-twin would need a pulley to half its rpm, but that would double the torque and make a multi belt clutch easy.

So, given that hp is about the same, are modern Chinese horses anywhere close to as strong as 70-year old American ones?

SAE horsepower calculations have changed at least twice since then which would make old numbers less compared to modern twice. The first time I know of, the early 70s, significantly.

I'd be more concerned about torque than horsepower. When I was kid, we had a Case 1370 tractor. It had 150 horsepower. I now own a Neon race car with 150 horsepower.

These are very, very different horsepowers.

Is the IH engine frozen due to sitting (rust), or mechanical failure?

It might be worth trying MMO in the cylinders and a breaker bar to free it up.

It will take a while, but once free it may surprise you and run decently enough to not bother with a swap.

Have you looked into resuscitating the current engine? Being locked up doesn't automatically mean that its dead. I used to have a neighbor that like to restore antique tractors, he brought quite a few locked up engines back to life without even opening them up.

He would take the spark plugs out and pour Marvels Mystery Oil, or Kroil down into the cylinders, after a few days of soaking he would put a breaker bar on the crank shaft and try to get it to move just a little bit. If it didn't move he let soak longer and come back at it with a bigger breaker bar, if it did move he'd keep coming back to it every day and move it a little more and a little more until it was free.

I saw him revive several Farmall model A engines this way. Including one pulled out of a swamp.

Sometimes those horsepowers are figured at different R.P.M. too. The Neon may have 150 at 5000 rpm and not so much at 2500 rpm while the tractor is 150 hp at 2500 rpm and at 5000 rpm is measured in blast radius.

egnorant wrote: the tractor is 150 hp at 2500 rpm and at 5000 rpm is measured in blast radius.

I LOL'd

On an old tractor like that, torque is what you looking for, so I'd look into some marvel mystery oil and break that engine free. Those tractors were built in a time where they were meant to last forever. They usually do, but they have to be maintained like anything with a carburetor.

I've used transmission fluid in a similar fashion.

I helped a friend many years ago who scored a late 70s fiat spider for next to nothing because of a seized engine. PB Blaster and MMO down the plug holes and a big breaker bar got it freed up the first night. The next day we were doing 7000+ rpm burnouts. As far as I know its still running today.

There was a local kid who took an old tractor and bolted a Chevy I-6 to the stock transmission..I don't remember the brand of tractor, but apparently the bolt pattern was the same? Anyway, I think he could have done some nice wheelstands with it once he got used to the throttle. He was pulling the front wheels 4"-6" off the ground as it was.

In a pure work situation, say pulling an already moving wagon up an incline, yes. When you try to get said wagon moving on said hill, you'll see the difference, much less energy stored up in rotating mass to help you out, and once that stored energy is gone it won't make as much power bogged down.

Dump a thin oil(diesel works) in the bores and forget it for a few days, then see if the crank moves any with a breaker bar(100 ft lbs tops). Assuming it hasn't been rained in, odds are you can get it moving again.

^this, exactly.

Oh boy.... I'll get back to you on this in the morning.

With tractor and mower engines both operating in such narrow rpm ranges I have to believe both are set to achieve their peak power levels in that band.

Since the mower engine spins faster it would have to have less torque than a tractor engine with the same hp. The thing is, if it is at peak hp and you gear it down to the same rpm as the tractor engine the math says the torque on the geared down shaft would have to be the same as a slower spinning engine, right?
With less rotating mass it might feel different, certainly, but what if I added a big flywheel? Same hp, same rpm (geared down), same mass (actually at a higher rpm it would need less mass, right), shouldn't it perform about the same?

Mathematically ( and theoretically) if the engines have equal HP you should be able to use gearing to get to the same peak torque.

The problem is that you will have fixed gearing for the motor to trans, the torque may only match at one RPM.

The torque curve measured at the input shaft to the trans will most likely have a different shape, and that will affect the performance of the tractor under a load.

A large flywheel may dampen the variation, but probably won't eliminate the problem, especially when under a heavy load ( uphill, running brush hog, mower, etc). The smaller motor may not recover as quickly due to a peakier torque curve.

I'll just leave this here.

http://www.yesterdaystractors.com/Farmall-M-Tractor-Parts.html

Motor is not a stressed member?

As seen previously on GRM:

https://m.youtube.com/watch?v=zFNv0fjQFZM

Streetwiseguy wrote: I'd be more concerned about torque than horsepower. When I was kid, we had a Case 1370 tractor. It had 150 horsepower. I now own a Neon race car with 150 horsepower. These are very, very different horsepowers.

This. Our old JD Model 40 was a 1.6l 2-cylinder. It was rated at about 17hp at the drawbar and maybe 21hp at the PTO. It would pull small trees out of the ground, drag big stumps complete with root ball, or drive a 72" single-blade rotary mower, and it towed a 22-ft wood and fiberglass I/O motorboat as if it wasn't even back there.

The amount of torques our 45 horse mahindra puts out @ 900 rpm would likely make that harbor freight motor cry.

Trakters iz about da torques sir, ferget the horsies.

Seriously, when it comes to working machines I don't believe the horses are the same size.

ebonyandivory wrote: As seen previously on GRM: https://m.youtube.com/watch?v=zFNv0fjQFZM

OMFG.

Toyman01 wrote: I'll just leave this here. http://www.yesterdaystractors.com/Farmall-M-Tractor-Parts.html

Can't be a legit tractor repair site. I checked the tools section and they offer neither a 3 lb hand sledge nor great big slip-joint pliers.

Forgive my earlier post... I just tend to open up massive cans of worms when it comes to hp/tq theory. I like to talk about it. :)

In theory, yes, you can put whatever size motor you want in there. Properly geared, torque will follow. For instance, if you have a 2L engine that makes 100 hp and 100 tq at 1000 rpms, you could replace it with a 1L engine that makes 100hp and 50tq at 2000 rpms and gear it down by a factor of 2. You will then be simulating 100hp and 100tq after the gear reduction.

One of the reasons tractor engines (like big rig diesels) are so low power is because of reliability. It would be easy to put good heads, better intake, bigger cam, and better exhaust on a tractor engine and make its output more akin to what its displacement suggests, but you would lose a ton of reliability. Like big rig diesels that displace 12L and make only 400hp at 1800 rpm. They could easily make 2000 hp, but they would fall apart at 100k instead of lasting a million miles or more.

I just did about 10 pullups in a little less than one minute.

HP = lift 33,000 lbs 1 foot in 1 minute. So, I lifted 2000 lbs (my 200lb body, times 10 pull ups) about 1.5 feet (estimating my difference in vertical position from pull up bottom to pull up top). 2k times 1.5 equals 3k, so I lifted a little less that 1/10th of 33,000 lbs 1 foot in a little less than 1 minute. I estimate I do pull ups at about 1/10th of a HP (and, I can only keep this up about a minute).

Torque = lever arm times force at 90 degree angle. I have a lever-arm (between my shoulder and elbow) about a foot long. Again, if I weigh about 200lbs, that makes my max torque about 200 ft lbs.

Even with all the gearing in the world, I will not be able to plow a field using my biceps as quick as a 22HP/100 ft lbs tractor can. (In fact, if I was in shape enough to keep at the pullups indefinitely, I estimate it would take me about 220 times as long, ha!)

Horsepower is what you are comparing, but lower-rpm/wider-band torque does have some (already mentioned) real world advantages in terms of using the HP.