a enginering folley on the cub engine.

[Super A]

I am getting into something I don't understand but I am just wondering.

It is nice to have some extra reserve horsepower. What if this problem is corrected, but the cub with the correction is still used as orginally designed. With the same type of implements etc. Wouldn't it last just about as long but would be able to have just a bit more hp to get the plow through that ten feet of tenacious clay Nebraska sometimes has?

Also seems to me porting does't hurt anything and makes the engine breath better.

Richard

What you are saying is generally true. If an otherwise healthy tractor is "souped" a little, within reason, but used with the same implements as before, generally you won't hurt the longevity of the powertrain too much. This was done a lot in the '60s and '70s and 80's with the higher hp diesels. A quick twist of the screw on the injector pump could give you a LOT of power and black smoke quickly! This is also what happened when farmers took their older letter series Farmalls and installed Fire Crater pistons, different governors, and so forth for more power, yet they pulled their same implements. For example, my Super A got a set of Fire Craters in the early '60s. Granddaddy always said that after that, it was able to pull the same load in 3rd that before it could only handle in 2nd. It didn't pull a BIGGER load, it just pulled it faster. When you take the same tractor, turn it up, and then pull a bigger implement, that is when you are apt to have trouble.


When you start talking about 25 HP Cubs, to me that is when it is time to find a Super A or a 140. I doubt you could take an otherwise stock Cub, at 25 HP, and be able to get all that power to the ground---it would take a lot of wheel weights.

Al

[George Willer]

Al,

We can't know how much the tractor was over-built, but in the situation you describe everything from the piston tops to the transmission input shaft is actually under more strain. Running in a higher gear has the same effect as pulling a heavier load. Whether that can shorten the life of the tractor... Who knows?

[Brandon Webb]

What would be the purpose of a 25hp cub? Yes a cub engine could produce that, but you'd have to re-engineer every other aspect of the drivetrain. Then it woulnd't be a cub.

[Phillip W. Lenke]

Braggin rights at BD Cub Tug!
Gentlemen start your engins!
Phil

[Eugene]

Horsepower always starts a great discussion.

Horsepower = Torque X RPM/5252.

1st gear = 2.4 MPH with 8-24 tires @ 1800 RPM. Cub Operators manual.

The easiest way to gain horsepower is to increase the engines RPMs. As the engine's RPM increases above 1800 RPM, the ground speed also increases above 2.4 MPH.

Just a thought. Is an increase in ground speed the desired end product?

Eugene

[Super A]

Al,

We can't know how much the tractor was over-built, but in the situation you describe everything from the piston tops to the transmission input shaft is actually under more strain. Running in a higher gear has the same effect as pulling a heavier load. Whether that can shorten the life of the tractor... Who knows?

George, I thought it was the opposite--higher gear = less torque on the drivetrain upstream from the rear wheels?

I know on our biggest tractor at home, (which is only "big" to us--120 HP) there is actually a warning decal in the cab to avoid pulling loads below a certain groundspeed. In other words, run as high a gear as you can.

I may be talking apples vs. oranges here.

Really to be "safe," it all comes down to what I hard an old farmer say once: If you need a bigger tractor, buy it.

Al

[Brandon Webb]

I agree, if you need more HP buy a Super A. Cubs were designed to be affordable. They Were designed to replace mules, not pull a 4 bottom plow.

[Clark Thompson]

I have had alot of people asking about making more HP in a cub engine. I decided to see if its really possible and cost affective to get the HP. I just want to see if a cub engine can be made to give more power. I beleive the drivetrain is capable of handling 25HP with no problem. everything International built is way overbuilt anyway.with the research i have done on this subject i beleive 25Hp is possible without going over 2200 rpm.it is going to be interesting when the engine is done. HOPEFULLY SOON!
I do have a superA and larger tractors. I did soup up the super A a while back. I did dyno it and it put out 26HP at 2000 engne rpm.

[cowboy]

Hi Al

George, I thought it was the opposite--higher gear = less torque on the drivetrain upstream from the rear wheels?

Lets say it takes 1hp to pull somthing 1 foot a second in 1st gear. Now you put it in 2nd gear but now you are pulling it 2 foot in one second and you need 2hp to do it.

OOPS I read it wrong. The higher the gear the less torque at the rear tires. Which means you need more power from the engine.

Billy

[wvpolekat]

Higher gear = more engine torque needed
Lower gear= less engine torque needed

[Super A]

Hi Al

George, I thought it was the opposite--higher gear = less torque on the drivetrain upstream from the rear wheels?

Lets say it takes 1hp to pull somthing 1 foot a second in 1st gear. Now you put it in 2nd gear but now you are pulling it 2 foot in one second and you need 2hp to do it.

OOPS I read it wrong. The higher the gear the less torque at the rear tires. Which means you need more power from the engine.

Billy

Yes but how does that translate into strain on the drivetrain? When you "juice" a tractor, that is usually what fails, and in most instances the failure is in the differential/axle areas.

Like I say, I am just about in over my head here!

Al

[evielboweviel]

strain on the drive train
if a 1/2" dia shaft is spun at 500 rpm with a given torque value then the same shaft at 1000 rpm with identical torque value will transmit 2x the horsepower
this is the reason PTO went from 540 to 1000 as the tractors got bigger
figure roughly 80hp transmitted as the dividing line much over that and you twist 540 shafts
another way to look at it is Oliver offered late 60's early 70's tractors in the 120-140hp range. if bought with front wheel assist then outboard planiteries were not needed, if bought as 2 wheel drive for tillage then outboard planiteries were installed to handle the torque thru the drivetrain and rearend to the ground at low speeds. If bought as two wheel drive for PTO work then outboard planiteries were not needed. Oliver 2050,2150
ron

[Dave F]

I'm really not interested in increasing hp in my Cubs, but if I was, I found that the quickest and easiest way to do it with a low tech engine would be to increase the compression ratio which the C60 doesnt have much of. When I was a younger kid than I am now I had a 59 Triumph sports car which actually had a overhead valve tractor engine adapted to a car. I had 1/8 inch planed off the head and had shorter push rods made to make up the difference. Had to use premium fuel to keep it from detonating, but it sure had a lot more power.

[Clark Thompson]

if you increase the compression ratio you will loose some low end torque. so it is best to try to keep the compression ratio as it is. in other words, if you raise compression ratieo you will have to raise the RPM's to a certain level to have the same amount of torque you had at a lower compression ratieo.Really HP doesnt matter much, its the torque developed that counts.for instance, a stock cub engine puts about 9.9 Hp. say you could install a single cylinder engine of the same HP in a cub tractor. It wouldnt performe well because of only 1 piston.also the engine with 1 piston would have to run 4 times as fast to produce the same torque as 4 pistons at a lower rpm.I am excited to see just how this cub engine turns out.I have discussed installing a turbo but everyone i have talke to who know about engines thinks the rods wont hold up with a turbo. so that is out for now.

[George Willer]

if you increase the compression ratio you will loose some low end torque. so it is best to try to keep the compression ratio as it is. in other words, if you raise compression ratieo you will have to raise the RPM's to a certain level to have the same amount of torque you had at a lower compression ratieo.Really HP doesnt matter much, its the torque developed that counts.for instance, a stock cub engine puts about 9.9 Hp. say you could install a single cylinder engine of the same HP in a cub tractor. It wouldnt performe well because of only 1 piston.also the engine with 1 piston would have to run 4 times as fast to produce the same torque as 4 pistons at a lower rpm.I am excited to see just how this cub engine turns out.I have discussed installing a turbo but everyone i have talke to who know about engines thinks the rods wont hold up with a turbo. so that is out for now.

Clark,

The produced torque is diminished by the effort required to compress the charge, and amplified by the resultant power increase, so it isn't always true that higher compression reduces torque.

Horsepower is completely independent of the number of cylinders, providing the number of cylinders of whatever size can provide the same torque at the same RPM. When you go back to basics it's the amount of true crankshaft torque developed at a particular speed that determines true horsepower unless you're Sears or a vacuum cleaner manufacturer.

Now, if we can find a way for Scruffy to develop the same horsepower with his well worn engine as Blackie can when running on white lightnin' we'll have a fair chance at CubTug III.

I hope you can get a turbo installed in time for the next CubTug. If you can get rid of the extra heat developed the rods and bearings will hold up just fine and you'll beat Blackie.