Hi, I have decided to try the truck pull at the county fair tomorrow evening. Mostly for fun, in fact all for fun, as I expect I won't even be close to the serious pullers.
It's a dirt track with a weight transfer sled. I have watched the tractor pulls before, and have a friend who will be there to help with advice. He was decent at tractor pulling years ago when he use to play with tractors.
My truck is a 61 f350 with a Detroit Diesel 6V53T. The wheelbase is about 15', so most all the weight will be on the front, and I don't expect to get much traction in the rear.
I have the hitch about as high as they will allow, and stuck out about a foot behind the truck to help transfer some weight. The rear suspension is from a smallish new Freightliner, and is much stiffer than any pickup.
I have dual 9R22.5 rear wheels with retreads with decent tread, but not really aggressive. I usually run around 80psi, any ideas on what I should run for pulling?
I think the idea is to get the sled moving as fast as possible and keep traction. So, I plan to take off in first gear which is a fast jog with the engine on the governor. Apply the fuel gradually and quickly while trying not to spin the tires, then hold it to the floor at a governed 2,800 rpm until I spin, loose power, or hit the finish line.
I only have less than a day before the pull, so I'm looking for advice, encouragement, or laughs, but don't have time for any major mechanical changes.
I built truck pull engines for about 10 years, mostly Mopar 440's, with a few Hemi's thrown in to make things interesting. The 440 would make a little over 700 HP at 6,500 RPM. The hemi with the blower was estimated at over 1500 HP, but we couldn't run it long enough to get a dyno pull.
Drop the tire pressure down to 50 PSI or so. Get the slack out of the chain, rev it up, dump the clutch, hope you don't break something getting moving, and watch the flagman. When you start to wheelspin, you'll get a red flag. Shut down as soon as you see the red drop! Good luck! Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
Only concern that comes to mind here is the slack in the chain b4 letting clutch out. Sounds like that can make your head/neck jerk. Then again, after looking at the impressive work you've done on old bolts, you've probably already thought about that & will be prepared for it. Hope you have a great time.
My best tip is to have your drawbar connect to your frame under the middle of your truck, & at the rear per the rules. Most guys pull from the rear bumper, which pulls down on the rear of the truck, lifting the front. A center connected drawbar will make the truck "squat" and pull more level. I out-pulled a lot of big-block, shiney, new trucks, that way with my old Dodge!
"Nothing is ever as simple as just turning wrenches!"
For antique tractor pulling, you want about as little psi in the tires as possible. 10-20. Think of it like this, when you've got low psi's, the tire is running flat on the bottom. That flat tire then begins to look more like "tank tracks" than a round tire. Too bad you don't have an agressive tread, that'll do more than anything.
Course antique tractors don't ever spin out, they just lose traction. 4-5 mph speed limit.
If you don't have a speed limit, get it going as fast as you can as early as you can. If you can add weights (is it a weight class restriction) sounds like you would want to add some weights behind the rear axle as far as possible.
Have a good time, make a lot of black smoke. The crowd will love to hear the sound of that screamin jimmy... not really a jimmy but close enough.
It was finally my turn to hook to the sled at 1:30 this morning.
I started off in second gear, but only went about 10 or 20' and stopped, I did not have the power to get moving, the engine was just lugging, and not picking up speed. So long as I don't go over 75' I am allowed a second try, and even a third.
So, I motioned to try again, and the powered sled drug me back to the start. This time I slipped it in first, applied a bit of throttle, and slipped the clutch out. Gently but quickly I planted the peddle on the floor. The RPM's slowly climbed from 1,000 to 1,800, and then jumped to 3,000, and settled down on the governor at 2,800.
It all seemed like slow motion driving down the track, I relaxed, sat back, kept the little peddle planted, and gently steered with ,my finger tips. When I finally stopped it felt like the pull only lasted an instant.
I ran out of traction and not power, although I don't think I could have gotten it started in 2nd, and definitely could not have shifted once moving.
205'!!! out of a possible 300. I was 7th in line in my class consisting of mostly stock appearing daily driven new and newish Ford and Dodge pickups. I pulled almost as far as the 6 guys in front of me, and perhaps farther than a few, I'll find out later. Quite respectable I thought, considering it was my first pull, and everyone else had four wheel drive. I actually pulled about 3 times as far as I had expected to.
I have some video that is really fussy, but with some decent sound. I'll try to figure out how to post it after I get some sleep.
I had a great time, the Detroit really sounded and felt good with a load...
I was hoping there was some video. Can't wait to see it. Good job Grigg. I bet you had a blast.
~ Billy Old Dominion Stovebolt Society: Exotic Animal Division 1946 Chevrolet Cab Over Engine | In the Gallery | Video | More pictures 1959 GMC 860 | Pictures 1950 Chevrolet 3800 | Pictures I've got a trailer and I'm not afraid to use it!
From talking with a friend who watched my whole class pull, he said I did better than over half of the trucks in my class, 17 total in the class. I believe I was the only 2wd truck. I am still trying to track down the official results. Grigg
Thanks, Yes, most everyone was surprised at how well the truck did.
If I pull again I will make some blocks to go between the axle and frame to limit the rear suspension droop. Apparently the sled pulled the rear down around 6", and I have some really really stiff springs!
I will also need to fabricate a stronger hitch, as the current one has no direct path for the load to go forward, it is not triangulated. It is sturdy, and plenty strong for a normal trailer, but it did bend the hitch back about 1/4" in the center. I would also give consideration to some more aggressive tires.
I really enjoyed pulling, and given a chance I am pretty sure I will do it again.
What I really want to do is sell the Ford before I am tempted to hook to another sled and chance braking something. Then finish my Chevy with the Detroit, and pull it, as I will be 100% sure of the strength and quality of the parts and my work. While the Ford seems to be nicely built, and plenty strong I just don't know it completely inside and out yet.
I did weigh the truck, not that it mattered for my class, and it weighed 9,775 lb with me and a friend in it. It should weigh nearly 10,000 with a full tank of fuel.
A full tank would have helped the weight and traction some, but that's a lot of money right now. I did have about 20 gallons in the 70 gallon tank.
I reduced my tire pressure from 95 to 65. I did not feel confident lowering them any more without some testing.
Great job. Wish I could have been there to see it. For giggles, if you pull again, you might try putting matching marks from wheels to tires in the back to see if the tires are spinning on the rims. As I understand it, as long as the tires don't break loose you can let more air out. Of course that was what we were taught for military 2.5 tons.
195? Chevy 3800 dump truck 1973 Chevy C30 cab and chassis 1987 Suburban 3/4 ton 6.2L Diesel
I believe the ideal air pressure is just low enough that with the full load the contact patch is still reasonably flat left to right. If you have any less air than that then the center of the tread will pucker up and give you less traction.
That, and not spinning the wheels in the tires is what you look for when letting air out for maximum traction.
