Over-revving?

[ScoutB]

Last weekend, while taking my 9N for a leisurely drive in the country, I encountered some very steep downhill grades. In 3rd gear at full throttle on those hills the engine revved higher than I've ever heard. Is it possible to damage the engine under those conditions? On one hill it got scary enough that I pushed the clutch in. Then it got even scarier, coasting at a breakneck 25 mph or so. :shock:

 

[Tom N MS]

I would not be in 3rd gear under those conditions.

 

[ScoutB]

I considered downshifting but it takes a while to come to stop, shift, and start again. Then repeat to up shift at the bottom. Also, I've had the same uneasy feeling in first gear going down a particularly steep hill in my back yard. I'm not used to engine braking with such a low compression engine. I wish I had a tach to know how fast it's turning.

 

[Royse]

I wish you had a tach too. Obviously extreme over-rev can
damage the engine, but we don't know what your RPMs are.
Governor not keeping them down to under 2000-2200?

I tried a Tiny-Tach which works well on most engines. They do
not work well on an N. The inductive pickup doesn't like the metal
core wires. I then had to cut open the water proof seal and short
two foil conductors together on the circuit board to reset it.
Seems like they could have put a reset switch on it so it would remain
waterproof, but that would add at least 15 cents per unit cost! LOL

 

[ScoutB]

I can say for sure that my average speed was 15 mph, which puts me around 1800-1900 rpm if the numbers from tractordata.com can be believed. Judging by the sound, my rpms increased by way more than 300 on those steep downhills. Should the governor prevent that?
Tiny Tach works great on my old 2 cylinder outboard. I'm glad you saved me the trouble of trying it on the tractor.

 

[Bob]

Since you have determined that the combination of slope, gear ratio, and engine braking doesn't work out well under the conditions you experienced, and you and the tractor survived, make a mental note not to operate the tractor under those conditions again.

 

[Dell (WA)]

Scout........would you believe they used the N-Engine in 1/4-midget racing in the 40's? and they turned close to 4000rpms. The N-Engine is what they consider 2-litters. (121cu-in) N-Engine is actually 119cu-in. Biggest problem they had was gittin' a carb rich enuff to turn 4000rpms. UP-draught carbs don't do it. They ended up using a DOWN-draft carb from early WW2 Jeep. What? You didn't know the N-Engine was used in the Jeep?

Hope you learned yer lesson about steppin' on the clutch pedal to slow down. That is what BRAKES are for.......respectfully, Dell

 

[showcrop]

Your original post states "in third gear full throttle". Did you really head down those hills with the throttle set at full?

 

[Dean]

Yes, of course.

Reduce the throttle.

Dean

 

[Money Pit]

yes low compression engine not the best for engine braking. i deal with hills pretty regular that wind the engine rpm up even going down in first gear. get it in a low gear don't push in the clutch a nd use brakes as needed. lot easier to keep it under control from the start than to try to regian control.

steep hill + full throttle + steep downhill sounds like a suicide run.

 

[lha]

These motors were also used in Model T cars and
trucks for years without trouble. My '41 9n almost
stops on a hill if I just lower the throttle
setting. I have a steep,long hill in front of my
house,and have gone up and down a couple of times.
Up in 3rd,low and down in 3rd high.Lowering the
throttle also lowers the setting on the
governor[actually the other way around],and slows it
down just fine. lha

 

[Dean]

Ford Model T engines are completely different from Ford 9/2/8N series tractor engines and share no components therewith.

Dean

 

[Tall T]

I still agonize over the day I fired up my Jube after not having started it for weeks and the RPMs shot up. After one or two tries with the throttle lever to bring the RPMs down I quickly shut off the engine. Started up again but knew nothing had changed so I very quickly turned it off and had a look at the linkage.

Problem was I had knocked the governor control rod off at the carb lever ball while replacing my fan belt.

I really wish I had known about this before it happened.

 

[JMOR]

(quoted from post at 12:11:23 11/14/14) Ford Model T engines are completely different from Ford 9/2/8N series tractor engines and share no components therewith.

Dean

nd..............It appears that the 4456 (six-tenths of one percent of WWII Jeep production) units are the only Jeeps that may have used the N tractor engine (modified). All the large production quantities, whether manufactured by Ford or Willys used the Willys engine design, not the tractor engine.

 

[Paul in Edmonton]

They ended up using a DOWN-draft carb from early WW2 Jeep. What? You didn't know the N-Engine was used in the Jeep?

They weren't used in production Jeeps. Just early prototypes when Ford was competing for the contract. My understanding is that the Ford GP, with the N engine, made for 4456 units of the 660,000+ jeeps built for WW2 (less than 1%).

The Willys "Go Devil" engine is actually one of the major reasons the Willys design was chosen over Ford's. When the Jeep went into full-scale production, Willys couldn't meet the demand, so Ford was contracted to build additional units (called the GPW, as compared to the Willys MB and the prototype Ford GP). But these were virtually identical to the Willys design, including the Go-Devil engine.

(Just an aside from an owner of both an N engine and a Go Devil engine...)

-Paul

 

[ScoutB]

Perhaps I should have put " breakneck" in quotes, I was never worried about my safety or the tractor other than the engine rpm. I tried throttling back on the hills but it didn't make a difference. It responds well to throttle position on flat ground. Does that indicate a problem with the governor? I don't have a lot of experience with this machine so I'm not sure how it's supposed to behave.
The road trip was a rare event. Usually I'm chugging up and down the hill in my yard. With a trailer in tow or a load in the carryall, first gear and throttled down, I still feel like the engine revs too high going down the hill. Maybe it's just the nature of the beast and I'm worrying over nothing.

 

[Royse]

On the bright side, if you can run it that fast and not have any
fear from the steering, you're in a lot better shape than most!
I would not expect the governor to hold it at a perfect speed.
I also would not think 18-1900 was too fast.
If I knew that speed was accurate.
I sent you an email too. Not sure if you got it?

 

[Dell (WA)]

yeah, Paul.......the N-Engined Jeep that I saw hadda "square" instrument panel like outta a Ford Car. The point I was making, the N-Engine will turn FASTER than the 1800rpms that ScoutB was worried about. Don't remember all the details, but there was some "funny-stuff" about the Bantam design that the Willys eventually built. Understand "Jeep" is a corruption of the Military "GP"...ie...General Purpose. Military "LOVES" to use initials to confuse us civies.......Dell

BTW.......the alternating "bar-tread" of military tires are NOT good traction tires like our 45deg tractor tires. The military bar-tread is so nobody can tell which direct the jeep is going

 

[ScoutB]

(quoted from post at 21:54:54 11/14/14) On the bright side, if you can run it that fast and not have any
fear from the steering, you're in a lot better shape than most!
I would not expect the governor to hold it at a perfect speed.
I also would not think 18-1900 was too fast.
If I knew that speed was accurate.
I sent you an email too. Not sure if you got it?

I just replied to that email.

My steering is not exactly tight but it seems to track really well - no wobble at any speed.

 

[showcrop]

(quoted from post at 19:15:45 11/14/14) yeah, Paul.......the N-Engined Jeep that I saw hadda "square" instrument panel like outta a Ford Car. The point I was making, the N-Engine will turn FASTER than the 1800rpms that ScoutB was worried about. Don't remember all the details, but there was some "funny-stuff" about the Bantam design that the Willys eventually built. Understand "Jeep" is a corruption of the Military "GP"...ie...General Purpose. Military "LOVES" to use initials to confuse us civies.......Dell

BTW.......the alternating "bar-tread" of military tires are NOT good traction tires like our 45deg tractor tires. The military bar-tread is so nobody can tell which direct the jeep is going

I always understood that the non-directional tires were so that they could not be mounted backwards.

 

[ScoutB]

(quoted from post at 22:15:45 11/14/14) The point I was making, the N-Engine will turn FASTER than the 1800rpms that ScoutB was worried about.

Thanks Dell. This thread hasn't brought out any horror stories of over revving engine damage so I'm thinking I'm OK.

 

[Royse]

Got the email, thanks!
I have the 19 x 4" tires on my 9N and 8N.
On hard ground they steer easier than the 6.5 x 16's on my 2N.
They're not so great in loose soil or ruts though.
I just replaced the front axle and pin on my 9N.
Guess I'll have to take it out in road gear to see
how much better it does!