How do you engine rebuilders torque the flywheel nut to 300 foot pounds? The RotaryAviation site shows two different ways...I'm just looking to see how everyone actually does it. Has anyone tried just setting the air compressor to the max setting and hitting it with the impact wrench?

Thanks,
Rich

 

There's a tip on nopistons.com that suggests you use a 3ft pole and slide that over your torque wrench and torque that to 100lbs and that should equal 300 ft lbs. Something like that.

 

You can use a 3 foot pole to give you extra leverage, but it won't multiply the torque created from the torque wrench. 100ft-lbs is 100ft-lbs, but with a 3 foot pole, it just means that less work is applied to make the 100ft-lbs. So, get a torque wrench that can handle 300ft-lbs, and a 3 foot pole, and you will have to torque it to 300. It will be easier to do because of the lever.
Daryl

 

Harbor Freight has a torque wrench that will go to 300 ft-lbs for about $69.

 

you can use your body weight. if you weigh 180 pounds, measure 2 feet from the center of the pilot bearing hole and stand with one foot on the pipe at the 2 foot mark when the pipe stops moving you will have put 360 ft lbs of torque on the nut.

lets say you weigh 170pounds then you stand 1.8 feet from the center and you will put 306 ft lbs of torque. to find what 1.8 feet equals in inches multiply 12inches times 1.8 this equal 21.6 inches. so a 170 pound person standing on a pipe at 21.6 inches will torque the nut to 306 ft lbs.

take your desired torque and divide it by your weight, this will give you the distance in feet you need to stand, then convert the feet to inches.
example:300 ft lbs / 190 = 1.57 feet. 1.57 feet * 12 = 18.8 inches or roughly 19 inches. so a person who weighs 190lbs can stand at 19 inches and will provide 300 ft lbs of torque. NO TORQUE WRENCH NEEDED!

 

Yea thats what I meant!

 

If you use your body weight without a torque wrench, take care to apply an even force and do not jump or bounce on the pipe.

I use a big torque wrench that is about 3 ft long itself, so no additional pipe is necessary. You might be able to borrow one from somewhere that services large equipment such as road graders, front end loaders, etc. If you borrow one from a military facility, they are usually calibrated regularly. Since accuracy is important, I would not recommend a cheap one from Harbor Freight.

 

Just go to a tire shop that does truck tires they have torque Wrenches that go up to 500 Ft-LBS for torqueing Truck tires.

Just see if you can rent one for an hour...

 

We're talking about people standing on poles while approximating their center of gravity to within a fraction of an inch on said pole, and you want better accuracy than an inexpensive Chinese torque wrench?

 

Yea, I can't believe you have to be too accurate when you're trying to torque something to 300 foot pounds. And I don't think I'm going to be trying to stand on a pipe to set it. I'll see if my local AutoZone has a long torque wrench that goes to 300 foot poundsthat they can lend out, or try the tire store as recommended above.

 

Hey, physics is physics. Just make sure you take into account your overalls, steel-toes, and safety glasses.

 

For all I know standing on the pole might be more accurate.

I wouldn't trust my engine to an uncalibrated torque wrench made from low-grade alloy by slave labour. But everyone can make his or her own choice. I buy a lot of stuff at Harbor Freight, but not the Chinese wrenches and $5 electric power tools. Once I made the mistake of buying a cheap slide hammer which jammed up on every stroke, and the puller attachment failed the first time it was used. Paying more for a better quality tool is better in the long run, and often the first time if the tool breaks right away or is out-of-spec.

 

Impact. I buzzed a nut off yesterday that had been on there for about a year. It came off fine.

 

ingersoll-rand impact to tighten it and remove it.

 

actually the range on the tightening torque is 290-360 ft lbs. so shoot for 315 and you will get in the range. it works believe me physics is physics. don't waste your money on a big wrench you will not use often. i used this method on my engine and my friends engine more than 3 years ago and there has been no problem. you have a 70 ft lbs range to get within that is a big range. don't forget to use some thread sealant. don't let people get you all freaked out about it.

i do recommend using a torque wrench on everything else when assembling the engine like tension bolts, manifold bolts, oil pump bolts, front hub bolt, oil pan bolts, stationary gears bolts, oil strainer, etc. be sure to buy a very small torque wrench to torque small bolts because i have seen them break with a 3/8 inch torque wrench.

 

I didn't use thread sealant on th enut and oil hadn't leaked out and damamged the clutch yet, but there was a film. Even RTV on the threads is better than nothing (even though that's generally not a good idea to gunk up threads like that). If anything, it acts as a low speed lubricant.

 

Just zap it with a spline drive 1" impact

 

I'm not doubting the physics and numbers...I'm a numbers guy myself. I'm doubting my ability to stand straight up on a pipe at precisely the right place

I just gotta believe that if I set my air compressor on the max @ 125 pounds, and hit it with the impact, that has to be good enough. But if I'm wrong. I'll go find an appropriate torque wrench.

 

the way we always crack the "big nut" is by straping the motor to a 2x6 with a come along, then i drive my 1/2 ton chevy up on the board. we drilled an old lawn mower blade and bolt it to the flywheel. craftsman 2 1/8 socket 25 $ and a 3/4in breaker bar craftsman 40$ and a 4 foot steel pipe. just jump on the pipe and off it comes. before we splurged for the 3/4 bar we broke multiple 1/2 in ****. good thing they were craftsman. also that front pulley bolt ( 19mm) claimed a good number of ratchets before we realized we were suppose to heat it up. so in theory where should i stand on my pipe when i put this **** back together? i am the worst at math. i weigh 145lbs.

 

Dude, you are the rarety in America Home of the Super size! go eat some more, and then ask that question

Kenn

 

not anymore. there's no super size option anymore >

 

This is lovely, even comes with pictures. http://www.specialpatrolgroup.co.uk/...ue/torque.html

 

1" gun is too much torque a 1/2" ingersoll is rated for a max of 390ft.lbs by the time you go through a 1/2 to 3/4 adapter and into a 2 1/8 socket you'll loose some torque so it puts you right at the max end of the range plus it removes the nut really easy even with locktite as long as you don't use stud and bearing mount kind.

 

weighing 145 pounds you need to stand 26.4 inches to get a torque of 315 ftbs. i would rather measure and use physics than guess with an impact wrench. to reach 348 ft lbs would mean you stand at 28.8 inches measured from the center of the eccentric shaft.

i have bent my 3/4 in breaker bar trying to get the flywheel nut off. i have never had to heat up the front hub pulley bolt to get it off, i just use a 1/2 adqaptor on my 3/4 breaker bar. yours must have been pretty tight.

 

Actually, this looks like it would be about as easy as anything else:

http://85rx7.home.mchsi.com/flywheelnut_torque.mpg