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Improving 720 diesel pulling performance

K

kdl

Member
I have had a 720 diesel for 22
years and have done some casual
pulling once or twice a year since
I have owned it. It's about 9,000
lbs on the dot. It's 100% stock .
It has the optional high speed 5th
trany ( so it doesn't have the
creeper low ) . I pull in 1st gear
NEVER come close to running out of
power . I have had firestone field
and roads and also sat2 tires both
perform about the same. I have
tried several tire psi high and
low.I put clevis on hammer strap
up on top of the drawbar . I
ALWAYS spin out without even
working the tractor . I did try
2nd gear once and it powered out .
What am I doing wrong ? Any advice
I would appreciate thanks guys .
 
So you very slow ? Way back on the throttle then ? It's hard to keep it from spinning out when I get close to 200 feet on up. I guess I need to practice working the brakes a little more to stop it from spinning out
 
dont use the brakes it will just screw u up. just keep enough to keep moving. even my 660 i have to run about 1/2 throttle or just spin out. and i pull with the 830's.thats the trick, and tires and pressure.
 
What size tire are you running? Taller the better if your stuck in first gear and can't use the power you have. Would your rules allow a 16.9 or 18.4-38?
 


The biggest problem is that you are pulling three weight classes too heavy. The fact that you "NEVER" run out of power in first gear is not significant. There are very few tractors ever built that will not spin out in first gear on a pulling track. Around here 720s, 70s and Gs pull in 5000 to 6000 lb. classes. One G used to pull in 4500. In the 9000 lb. class you are pulling against 100 HP "stock" tractors. So get rid of some pork, enter the 6,000 lb. class, put 'er in second and give 'er full throttle and join the fun. Once you are in the ball park you can tweak tire pressure and weights and throttle position according to track conditions. Then for the next season you can get your HP doubled or if you want save some money get an Oliver, Minnie Mo, AC, Ford, or Farmall and get the HP doubled for half as much money as it will cost with your 720. Go onto You Tube and enter a search for "Uncle Buck at Deerfield Fair.
 


The biggest problem is that you are pulling three weight classes too heavy. The fact that you "NEVER" run out of power in first gear is not significant. There are very few tractors ever built that will not spin out in first gear on a pulling track. Around here 720s, 70s and Gs pull in 5000 to 6000 lb. classes. One G used to pull in 4500. In the 9000 lb. class you are pulling against 100 HP "stock" tractors. So get rid of some pork, enter the 6,000 lb. class, put 'er in second and give 'er full throttle and join the fun. Once you are in the ball park you can tweak tire pressure and weights and throttle position according to track conditions. Then for the next season you can get your HP doubled or if you want save some money get an Oliver, Minnie Mo, AC, Ford, or Farmall and get the HP doubled for half as much money as it will cost with your 720. Go onto You Tube and enter a search for "Uncle Buck at Deerfield Fair.
 
get it down to class 4 (8500)max. instead of class 5. i pull my wd40 in class 5 i dont spin out and weigh 10k.and i know the 720 i have no problem overtaking it. out pulled r,820 and 830. i take it this is the real antique tractor pulls.
 
The 720 I have is all stock and I
see no way to loose 3000 pounds
unless I cut in half . I'm pulling
in 100% stock class
 
ya , its a class 4 tractor. might have to loose some fluid in tires. get her to smidge under 8500 with you on it and good to go.
 
3 most important things. Traction, traction, traction. Most everyone spins out. I’ve been pulling stock class for 25 years and spend most of my time looking for tires I think may work better than what I have. I have never seen a stock SAT that worked very well at all so if they work as well as your field and roads they may not be worth a dam either. Just keep looking, buying and trying. There’s nothing more you can really do. Short of starting over with a Farmall.😀
 
yep, it is almost boring watching those john deere's put put down the track at idle and yes when reved up the will spin out. ihc is way more balanced tractor and will sooner power out on good traction. my 660 does very well . and dont see any ihc's with he front end in the air either.
 
You guys just keep pulling at 1/2 throttle, and I will too but I'll have enough motor to spin my tires 4 times faster at the end. Who do you think will win. Just kidding guys. There is nothing works every time.
 

But what Lee460 and Rustred are not telling you is that yes, it is all about traction, BUT, when you have some MOMENTUM you are less dependent on your traction until the very end. This is why they have speed limits. You need to be just under the speed limit in order to make use of momentum. When you get your tractor and the sled moving just a little faster, you have the energy of momentum or inertia added on to the power of your tractor. Being less dependent on tire traction enables you to pull through that soft spot where someone else spun out. You are puling onto the track with 2,200 lbs. more than your tractor was originally shipped with. You can remove that and more, get into 2nd gear, get some momentum going, and stop giving away a huge advantage to the other guys. You need to also understand that unless the top finishers are getting dynoed, that you are pulling against tractors with significantly more power than stock.
 
Welcome to pulling lesson 101. all good advice, however many more little things enter the picture when you reduce weight, properly made and placed weight brackets are much more important, then knowledge of your tractor, driving skills, timing, track reading, fuel used, other settings, winners have the ducks in a row, not just random luck on many areas to be considered, - it is not certain to win with more power, but it does make it easier.
 
6,800 lbs ? That's what pony start
720 diesel should be ? Ok yes mine
has wide front, three point, dual
hydro , and 2 sets of rear weights
..........but my brother has my
grandpa's pony start 720 diesel
with narrow front, no three point,
single hydro, no wheel weights and
it weighs 7,800 . Remember I can't
"strip it down" it needs to be
stock. If someone can tell me how
to get a pony start 720 diesel (
even my grandpa's with nothing
extra at 7,800 ) to 6,800 I'll
will try and do it ...... without
filling the tractor with helium !
 
(quoted from post at 09:32:04 12/29/20) 6,800 lbs ? That's what pony start
720 diesel should be ? Ok yes mine
has wide front, three point, dual
hydro , and 2 sets of rear weights
..........but my brother has my
grandpa's pony start 720 diesel
with narrow front, no three point,
single hydro, no wheel weights and
it weighs 7,800 . Remember I can't
"strip it down" it needs to be
stock. If someone can tell me how
to get a pony start 720 diesel (
even my grandpa's with nothing
extra at 7,800 ) to 6,800 I'll
will try and do it ...... without
filling the tractor with helium !
Click to expand...


It appears that you need to take a look at the rules. I have been pulling since 1998 and have never encountered a rule that you have to have a three point hitch on a tractor just because it was available at the time.
 
Going to be hard to hold 14-9's to the ground even with that amount of weight. What air pressure are you running? My 720 stock diesel w/pony and 15-5's and fluid in the tires weighs right at 9500. I pulled it once in the 10500 class and finished 2nd. Had it in 1st-all of 1.2 mph. Tires were wrinkling pretty good but spun out at the end.
 
I have experimented with pressure and have only been as low as 10 psi but should I go lower ?
 
(quoted from post at 18:06:57 12/29/20) I have experimented with pressure and have only been as low as 10 psi but should I go lower ?
Click to expand...


The best tire pressure varies with track conditions, as does drawbar length, and proportion of weight front to rear.
 
Showcrop , my brother has my grandpa's old 720 diesel pony start it has NO three point ,NO wide front , No dual hydro ,NO fenders , NO weights and it weighs 7,800 . Explain to me how I can take something off that to make it 6,800 , please let me in on the secret
 
if you move that hitch in to 20 inches from the center of the axle and 20 inches high ( where most rules say you may ) you will get lots more traction and soon run out of that 54 hp a jd 720 diesel has .
 
9500 class you need to go higher. When you get done pulling look at your tracks where you spun out. If they are humped up in the middle, your pressure is low. If they are dug down in the middle it is to high. I bet your way low for that weight class.
 
I would say you have 2 strikes handicap from the start. Tire size and ground speed. I am guessing you are pulling with tractors running a good bit larger tires. That weight would include tractors like GB and GVI Minneapolis moline that came with 18.4x34s. Next: how much lug is on your tires? A near full tread is great for the field but a near worn out tire with nice road wear is best for a packed pulling track. Next is ground speed. You want as much momentum as you can get as fast as you can get it. How about RPM. turn everything the rules will allow
More rpm equals more speed. Be sure your drawbar is consistent with the tractors that are winning
Usually as short and hi as rules allow but not always. Remember, every track and sled is different. Watch look and listen.
 
(quoted from post at 18:10:04 12/29/20) Showcrop , my brother has my grandpa's old 720 diesel pony start it has NO three point ,NO wide front , No dual hydro ,NO fenders , NO weights and it weighs 7,800 . Explain to me how I can take something off that to make it 6,800 , please let me in on the secret
Click to expand...

Kdl, There are NO SECRETS among serious contenders in tractor pulling. A stroll around the pits will reveal the differences between as sold and as equipped. Before the pandemic I have pulled for many years with two Fords, a 960 and a 9000. The 9000 had a shipping weight of 10,600, and in different years I pulled it at weights from 7,800 to 13,000. While I am not suggesting that you go to the lengths that I did to remove weight, this illustrates what is possible. At one pull some years ago in Massachusetts I entered six classes and won four of them. The two lightest and the two heaviest. There are many lightened parts available for your tractor, many have been discussed over the years here. The most common is to replace cast rear centers with pressed steel. Another is to eliminate the PTO and install a "flatback". There are many after market repop parts made of aluminum such as the pedestal, and often a smaller radiator or starter is swapped in. I am not a "Deere" guy so I don't know the specifics, but you could find out by simply observing the 720s 70s and Gs pulling in 6000 to 8000 and checking them out. I am not suggesting that you do any or all of what I have mentioned or what you may see, but you asked how to make your 720 lighter and how to be more competitive. Here is my 9000.


mvphoto67468.jpg


mvphoto67469.jpg
 
Nice looking Ford--I have always liked that series. Do you have any Forrestal-sp? parts in it--As you know-they can make a Ford run!---Tee
cvphoto69428.jpg

Don't know who this is but in sure is pretty
 
yes, i know what your talking about, stock antique pulling. there is no such rules for ground speed , dont know how momentum comes into play when your pulling at 1 1/2 mph. its what ever you do to make your tractor pull the farthest. being it tires, rpm, hitch height, gearing, weights, air pressure. i have pulled my 660 many times with 6-8 psi in the tires. pull in class 6 with it weighing 12,000 lbs. pull in low gear with 1/2 throttle. got many firsts and seconds. at one pull here couple years ago we had six 660's the ones that give her full throttle just spun out , the ones that used second gear power out. and you dont want the front end up in the air as it lowers your hitch height. the old mccormicks and international are pretty well balanced and dont really lift but i have had mine off the ground in good traction. also you dont want to be too light or you wont pull either . that is a class 4 tractor as i said, weight it to 8500 and it will pull. our tractor cut off year is 1960. where are you pulling at?
 
(quoted from post at 07:04:30 12/31/20) Nice looking Ford--I have always liked that series. Do you have any Forrestal-sp? parts in it--As you know-they can make a Ford run!---Tee
<img src="https://www.yesterdaystractors.com/cvphotos/cvphoto69428.jpg">
Don't know who this is but in sure is pretty
Click to expand...

tee, I do have some Forrester's parts in it. They also pointed me to some guys for injection work.
 
If you are running 6-8 psi at 12000# - you are giving up several inches of hitch height for sure.But if that works for you, Kudos, but not for most.
 
The FARMALL pullers know how to set their hitch height. Son & I followed a coworker around every weekend watching him pull his 77 Oliver, which would have had more in common with a 1950 Gas tractor if Oliver had built one. Not many 2 cyl Deeres pulled with that club. Not sure why. Watched a 4000 Deere diesel run out of power around 240-250 feet one afternoon in a 8000# or 9000# class. One tractor left in the class, nice very stock appearing Super M. He was running very close to stock RPM, probably 2nd gear, he pulled the frt tires off the track around 220 ft, they never got over a foot off the ground. He spun out a bit beyond 300 ft. I know a couple of those Super M's had over 550 CID. This was Tri-County Pullers in southern Wisconsin 30 years ago. SCREAMIN NORWEGIAN still pulled with them with a 1066. Every Fireman's Festival had a pull.
 
Not really. I have to keep tire psi down to keep hitch height at 18”. Other wise I am over by an inch.
 
(quoted from post at 15:29:19 01/02/21) The FARMALL pullers know how to set their hitch height. Son & I followed a coworker around every weekend watching him pull his 77 Oliver, which would have had more in common with a 1950 Gas tractor if Oliver had built one. Not many 2 cyl Deeres pulled with that club. Not sure why. Watched a 4000 Deere diesel run out of power around 240-250 feet one afternoon in a 8000# or 9000# class. One tractor left in the class, nice very stock appearing Super M. He was running very close to stock RPM, probably 2nd gear, he pulled the frt tires off the track around 220 ft, they never got over a foot off the ground. He spun out a bit beyond 300 ft. I know a couple of those Super M's had over 550 CID. This was Tri-County Pullers in southern Wisconsin 30 years ago. SCREAMIN NORWEGIAN still pulled with them with a 1066. Every Fireman's Festival had a pull.
Click to expand...


Dr. Evil, At pulls around here it is very unusual to see a hitch that is not adjustable over a broad range of height on any color tractor. The Farmalls around here run mostly 6.7 Cummins diesels.
 
depends on where you pull, good hard sticky clay track you will lose several inches, fix hitch to proper level to start, removing air to make height is for emergency use only. LOL
 
The guy asked for info on antique tractor pulling,.... and things sure got off his subject.
 
(quoted from post at 22:42:15 01/04/21) The guy asked for info on antique tractor pulling,.... and things sure got off his subject.
Click to expand...


Yes, rustred, conversation wanders. Unlike a corporate or municipal meeting with a moderator or chairman to keep the discussion on topic we are more like a coffee shop where discussion is free to constantly change topics. Perhaps you could apply for a moderator position on the board.
 
Tractor data list the 720 at 6790 lbs. with a 12-38 stock tire . At 9000 lbs that should pull nicely. So whats the problem ? can we suggest something to improve his distance?
 
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