torque Antique tractors

I was wondering what kind of torque some of the Antique tractor make. Farmall H & M, Allis wd45 and such. I see truck ads about torque & they have a lot of rpm's to get it.

well to be honest ,thats not exactly true.one of the problems with a internal combustion engine is that torque falls off at high speed while hp increases.Look at some torque/ hp curves on various engines to see how this works. If you will notice ,if you have a chance to drive different vehicles, most vehicles these days running down the hiway these days are running at between 1800-2200 rpms. Thats generally the peak torque range of any engine.Let me try to give you an example of torque. Say you are trying to break a bolt loose with a 3/8 ratchet,you pull as hard as you can and it wont come loose,so you get a 1/2" ratchet pull on it and it breaks free.What have you changed? torque. a engines torque is set for the most part by the length of throw from center of crankshaft,to center of rod bearing journals.the longer this distance the more torque.BUT thats limited by a little thing called reciprocating mass.The longer this throw,the less rpms you can normaly run without engine simply flying apart due to mass.Take a engine out of a semi for instance,not unusual to find one with 1200 fts torgue with not what you would consider any great hp ,but if you rev that engine up as high as say you could a honda or bmw it would fly into a jillion pieces.To overcome this stock car racers and folks destroke them,simply put in a crank with less throw,longer rods to make up the difference and biuld a engine thats designed to run at high rpms. Thats why those folks use a flying start when racing,not enough torque at low speeds.On a pickup or family driver we want a trade off,we want good torque to pull trailers and things,but we want hiway performance also.That truck that you see advertised as having the highest torque is simply one that probably wont be as fast as others.AND it, if you could read the fine print,is just on a certain engine package. Heres the bottom line, torque does the work,hp is how fast that work gets done.

The problem with Rpm's is ??? Torque isn't power. Rpm's isn't power. T X RPM / 5252 = power in HP

so you are one of the hp = power people? thats a typical american way of thinking,weve grown so used to high hp,but hook a 200 hp tractor and a 200 hp car together and which will pull the other?most likely the tractor,simply because of more torque.even if they weighed the same.power is a suggestive thing. power for a car is not the same as power for a tractor.that little factor is why folks who put v-8 engines in a tractor dont generally get the gains they expect.of course you could argue that gearing a tractor down is what makes it pull better, but does that increase hp or torque? bottom line is hp is a measurement of speed,torque is a measurement of work done. of course a 100 hp tractor should do more work than a 20 hp tractor,but you would expect torque to climb also.but that doesnt mean with 2 100hp tractors one wont out pull the other.

Just add enuf gears, an you can pull a freight train with a washing machine motor.

The general rule is a peak of around 1 ft lb for every cubic inch, give or take. (That number has not changed appreciably since the beginning.) A 450 size car engine generally makes 500 or so etc. Old tractors tend to be in the ball park (usually less) but peak out down around 800 to 1000. The old machines just turned sooo ssslooow... Getting the RPM up to make useful power is an ongoing struggle, but nowadays usable rpm seldom goes over 2500 for efficiency reasons.

It is the height of silliness to compare apples to oranges . We are talking torque and HP. Why would you introduce some fool idea of comparing a 200HP field tractor which is about useless for driving to work and hauling a travel trailer cross country to a 200HP car . The car would walk all over the tractor. Hauling the trailer farther and faster on less fuel. Too those who failed high school physics, HP is HP. What you miss and mistake is torque rise as the motor is lugged below rated HP Rpm's. It's the same problem as many folk unaware of an electric motor's torque rise. They walk around thinking 5HP electric can do as much work as 10HP diesel.

It is the height of silliness to compare apples to oranges . We are talking torque and HP. Why would you introduce some fool idea of comparing a 200HP field tractor which is about useless for driving to work and hauling a travel trailer cross country to a 200HP car . The car would walk all over the tractor. Hauling the trailer farther and faster on less fuel. Too those who failed high school physics, HP is HP. What you miss and mistake is torque rise as the motor is lugged below rated HP Rpm's. It's the same problem as many folk unaware of an electric motor's torque rise. They walk around thinking 5HP electric can do as much work as 10HP diesel.

(quoted from post at 15:39:04 02/27/12) I was wondering what kind of torque some of the Antique tractor make. Farmall H & M, Allis wd45 and such. I see truck ads about torque & they have a lot of rpm's to get it.

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If you know how many HP the tractor is rated to put out at a certain RPM, you can get torque

Torque = 5252 * HP / RPM

Or, for the math impaired, multiply your HP by 5252 and divide that by the RPM the tractor makes that HP at.

thats not completly true either,lots of older engines were used in both cars and trucks,but trucks had higher torque even with the same transmissions and gears.the reason ? different crankshaft with a longer throw on crank .cant pull a freight train with a washing machine engine,cant get enough power to move the gears required let alone the train.heres a thought lets all pull our engines out of our tractors and replace them with lawnmower engines. my n has about 25 hp,i could simply replace it with a 25 hp briggs right? same hp. so what would be the difference? simple no torque,lawnmower engine has a crank with maybe 2" throw on it,n engine has over 4" so it simply developes more torque.what about a 2cyl john deere? many two cyl lawnmower engines make more hp,and run more fuel effecient, why not use them? again no torque. same way with that old 3/8 - 1/2" ratchet thing,you cant pull any more than your strenghth allows,but you sure can develop more torque by getting a longer wrench.but.. which wrench can you move faster when spinning a nut off? the shorter one of course it doesnt have to travel as far,so it technically has more hp!because hp is a product of rpms!

Sorry to inform you but you and teddy26food have a similar understanding of physics. Do you understand "torque rise" and how it applies to different kinds of engines and motors as they are lugged from peak HP rpm? Keep the same displacement, half the stroke, double the piston surface area and crank torque will remain unchanged. Try putting a 25HP Briggs and a 25HP farmall engine on a generator. Amps ,volts and frequency will be identical when either engine is operating at max rated HP. Are you by chance familiar with cam timing, port velocity, port volume, valve size and rpm?

yep i understand torque rise.try this, hook that briggs and farmall up on 20-25kw kw generator ,slap a load bank on it and youll understand torque,farmall will load up and keep humming,briggs wont make half a turn and lock up.If we could run a briggs engine on everything,as effeciently as they run,why do we run anything else?,

Do you understand inertia from rotating mass? Do you know what power is and what torque is ?

Do you understand inertia from rotating mass? Do you know what power is and what torque is ?