Ford Horsepower

[Mike Groom]

The Ford tractor 4 cyl. is rated about 23 HP,the Ford truck 4 cyl.built till about 1947 has the same bore and stroke,and from what I've been told is a tractor engine also used in Fords GP for the military, is rated at 40 HP,is the rating checked different or what am I missing here?

 

[wisbaker]

The truck and jeep motors weren't governed to the 2000 rpms the tractors were.

 

[Mike Groom]

Did they have governors at all or how did the carb-throttle linkage work? Thanks, Mike

 

[jackinok]

thats correct,hp increases as engine speed does.up to a point of course.basically hp is a measurement of speed work can be done.that engine is limited to a gov speed of 2200 in a tractor simply because thats most likely the top of the torque curve.( actually the proper operating range of a n engine is 1500 rpms which is probably ,though ive never seen a torque /hp curve on one of these engines,close to the high end of torque curve if i were guessing)thats probably ,again if i were guessing, where fords engineers calculated the most effecient torque/hp/ fuel economy to be. a tractor which is pulling a load constantly is more dependant on the amount of work (torque) that can be done than on the speed (hp) of which it can be done,so most are simply governed to those rpms that fall at the upper end of the torque curve. An auto rolling down the road in high gear doesnt need as much torque so they simply increase engine rpms,which increases hp ratings.

 

[jackinok]

the linkages on my old ford military jeep was simply a standard mechanical linkage found on most cars of the time,with no governor.I dont recall if it had a seperate throttle linkage that would hold engine at a set rpm.My 59 jeep pickup did but it had a willeys hurricane engine so no relation at allto the ford.

 

[Ultradog MN]

Horsepower is a function of torque X RPM.
So if you increase the rpms on an N engine you'll get more than the 23 HP - but as Jackinok says - to a point.
Photo is of a Ford built war time GP. Note the modified distributer and the downdraft carb.

a few more photos here

 

[Mike Groom]

Thanks guys! I learned something today and never thought about governing the engine as a HP difference between the two. Mike

 

[Paul in MN]

Besides the other poster's answers which are good, there is a fundamental difference in how Hp is measured in a tractor vs a car or truck. With much research done in the early 1900's by the University of Nebraska to compare all tractors by a standard testing method, it was decided to rate tractor Hp by the Hp delivered by the rear wheels to the ground (or by the PTO delivering Hp to a dynamometer. In both cases, the engine is fully equipped with its parasitic loads from the generator, fan, water pump, transmission gears/bearings/oil, ring and pinion, and finally tires, with friction losses in every part of the system.

By contrast, the truck and car engines were rated at Hp put out at the flywheel on a bare engine mounted on a test stand. The test engines usually did not even have to turn a generator or water pump. Of course this leads to a higher Hp number which helps sell the car or truck.

So a 40 Hp engine turning at an uncomfortable high speed (which leads to a short life if run this way continuously) becomes a 23 Hp engine run at a speed which it will sustain for thousands of hours, and it is dealing with the friction losses of the entire machine. Yup, same engine, same compression ratio, same fuel.

Paul in MN

 

[Ed S.]

Photo is of a Ford built war time GP. Note the modified distributer and the downdraft carb.

Also note the front-mount distributor!



es

 

[JMOR]

(quoted from post at 18:22:24 02/21/12) Horsepower is a function of torque X RPM.
So if you increase the rpms on an N engine you'll get more than the 23 HP - but as Jackinok says - to a point.
Photo is of a Ford built war time GP. Note the modified distributer and the downdraft carb.

<img src="http://i61.photobucket.com/albums/h56/Ultradog/Ford%20GP/HPIM0271.jpg">
a few more photos here

adly, it appears someone has stuck some junk automobile dash assy in that jeep.

 

[JMOR]

(quoted from post at 18:32:04 02/21/12) Thanks guys! I learned something today and never thought about governing the engine as a HP difference between the two. Mike

P=torque times rpm divided by 5252. So the peak HP will be at the point along the curves shown where rpm is rising and torque is falling and there product is maximum.

 

[1951 8N PA]

Sadly, it appears someone has stuck some junk automobile dash assy in that jeep.

I believe the instrument cluster is original to the Ford GP.

 

[Cliff(VA)]

Don't confuse a Ford GP prototype (at least 1500 were built for testing in the great Jeep contest) and the later Ford GPW of WWII.

The GP had a Ford 9N engine and a flat cluster.

The GPW had a Willy's Hurricane engine and round gauges. It was an identical design to the Willy's built MB.

Most of the GPs were shipped to allies at the beginning of the war so that we would not have to keep separate spare parts. The MB and the GPW were the work horse jeep of the war.

Cliff(VA)
A history of the development of the Jeep

 

[JMOR]

(quoted from post at 00:46:34 02/22/12)

Sadly, it appears someone has stuck some junk automobile dash assy in that jeep.

I believe the instrument cluster is original to the Ford GP.

ay be...but it just doesn't look right....and a 100MPH speedometer?!

 

[Cliff(VA)]

I don't know why the 100 mph speedo, but the cluster is straight out of the 1941 Ford civilian trucks.

Cliff(VA)

 

[JMOR]

(quoted from post at 16:26:57 02/22/12) I don't know why the 100 mph speedo, but the cluster is straight out of the 1941 Ford civilian trucks.

Cliff(VA)

f govt didn't specify something different, then it does make sense that they would use existing hardware for a prototype. I did find another picture showing that same dash.

 

[Ultradog MN]

I think Cliff is correct. Ford used the same instrument cluster from a civilian vehicle in their GPs. I did ask the owner about it and he said the GP dash was painted OD like the rest of the vehicle but an original cluster was extremely rare to find.
Little story -
The owner was a WWII Vet - real nice old fellow but kind of frail now and kind enough to let a stranger take some photos of his rig. When he told me he was Navy I went to my pickup, grabbed a brand new hat I had just bought, put it on his head, told him to keep it and thanked him for his service.
Kind of a spur of the moment thing -
And a warm fuzzy feeling was shared by all...

PS you can see there is no governor on the engine either.

 

[Ken(Ark)]

(quoted from post at 16:46:43 02/21/12) The Ford tractor 4 cyl. is rated about 23 HP,the Ford truck 4 cyl.built till about 1947 has the same bore and stroke,and from what I've been told is a tractor engine also used in Fords GP for the military, is rated at 40 HP,is the rating checked different or what am I missing here?

Yeah , but my tractor will do a wheelie !

 

[Ken(Ark)]

(quoted from post at 16:46:43 02/21/12) The Ford tractor 4 cyl. is rated about 23 HP,the Ford truck 4 cyl.built till about 1947 has the same bore and stroke,and from what I've been told is a tractor engine also used in Fords GP for the military, is rated at 40 HP,is the rating checked different or what am I missing here?

Ford 226 flat sixes were used in the funk conversions and are rated at 95 hp at 3500 rpm . Its more like 55 hp at 2000 rpm where a tractor works .