[CAMARO]

I just swapped a 10 bolt rearend for a 12 bolt in my 68 camaro. Now my drive shaft is too big. A guy I work with, who races late models, says that he makes his own driveshafts all the time and could make me one as well. He balances them by dumping a quart of oil inside before welding them shut. He claims that the oil finds the low spots through cintrifical motion. Is this possible?

[M&M CUSTOM]

How can that work? You started out by saying that he "claims" this method works.
From an engineering standpoint your quart of oil will automatically find the lowest point and stay there "gravity helps this happen" most likely the rear flange.
When the shaft is put into motion the oil will be forced outward to the tube wall and stay in that location or close to it through centrifugal motion.
If it flows to anywhere else before put into motion you will then develope oil "rings".
In this whole process NEVER actually solving the actual imbalance. If that were to actually work why don't the manufacturers "any of them" do this.
And forget winter cold weather driving, the oil would flow much slower and only compound the whole problem.
Don't mention the oil balance method to anyone in a driveshaft shop, trust me.

[willys36@aol.com]

Works great! I also balance my wheels by packing the light spot with a handfull of mud and balance my engines by flame torching off the heavy spot on the counter-balance weights. Also I balance my checkbook by winning the lottery twice a year.

[Will's41]

Too Much, now that's balance!

[85406]

I sure would agree with the others on the snake oil balance. Would you have the exact difference you need for the shaft between the 10 bolt and the 12 bolt as I am doing one also. I have heard that someone like moser has a pinion yoke that is shorter and ends up the same as a 10 bolt. Only hear say.

[axle bastard]

as well as setting up axles, i ballance/rebuild drive shafts 6 days a week.
i wouldn't waste my time with the oil thing.
i wonder how this guy gets them straight before he welds them?

[4 Jaw Chuck]

If balancing anything was as simple as filling it with a liquid wouldn't you think that everything would be balanced that way?

OLD WIVES TALE!

Maybe discuss the electron transfer theory of battery discharge on concrete floors with him, then go somewhere else. Oil acts as a dampener for harmonics thats all, balance has nothing to do with it.

[bigwildgrin]

just a thought here, but centramatic sells a balancing disk for semi trucks. its basically a disk that bolts on behind the rim and is filled with 22 oz of sand. if this works for balancing tires, and I'm not sure it does but they do sell a lot of them, than wouldn't sand in a drive shaft balance it? anyone??

[Jason]

Why re-invent the wheel? Balance it right like they have been doing it for the past 100 or so years.
You can try to oil balance your driveshaft if you want. You can also try to get someone to sand balance your tires. It's your time and money...I prefer the good old fashion way...With weights.

[woodz428]

I believe it will work, they used to use a similar thing on tires. HOWEVER, it would have to rebalance every time and would be out until then, what may work on a periodically run race car is not neccesarily a good idea on a street cr. Locally we can get a driveshaft with new yoke and bothe u-joints for $185, and that's always balanced. I'd go for the real deal.

[bigwildgrin]

well, yes, I balance them with weights too, but it is not an exact sience. no matter how good you are it will never be perfect, and yes I realize that perfect is not necessary, but if the sand or oil method worked it would be perfect, plus simpler and faster. which is always good...

[woodz428]

Something not considered is also the extra weight of the sand and how the viscosity change of the oil at lower temps would create an out of balance longer since it would take longer to flow out. That's what I meant by racing applications aren't neccesarily good for the street. I've used several of these driveshafts (that's all he does) and never had any problems, he can also make an aluminum one if you are concerned about an out of balance problem, but generally it's unneccesary.

[dmorris1200]

Hey you know my washing machine often shakes when in spin cycle. Do you think it would help if I poured a quart of oil in her to balance the load??

[chrismac]

hey i did that one time in my sleep. When i took off the thing fell out and i was looking to buy another and my buddie said use duck tape.

[4 Jaw Chuck]

Could someone explain to me how oil being thrown about by centrifugal force will move opposite the low side to the high side to cure an imbalance? Not physically possible.

For the record I don't balance driveshafts I true them, if they runout less than 0.002" there is nothing to balance. The reason why driveshafts are balanced is because they are so poorly made from the factory that the tubes are egg shaped and runout on some I have seen are almost 1/16" out! Cut the ends off and weld in some straight mechanical tubing in it's place and all of a sudden balancing becomes unnecessary. The diameter of the tube in comparison to it's length means any imbalance will have a very small force couple.

One of the members of this board has a driveshaft I made for him for his BMW racecar and I only trued it before delivering it and he has no problems at 160MPH...no oil...no sand...no magic.