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Re: Shortening a driveshaft yourself
[Re: burdar]
#1111410
11/11/11 06:39 PM
11/11/11 06:39 PM
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Joined: Jan 2003
Posts: 74,942
U.S.S.A.
JohnRR
I Win
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I Win
Joined: Jan 2003
Posts: 74,942
U.S.S.A.
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Quote:
I had a driveshaft shortened at a metal fab shop once. What you described is exactly what they did. I never had it ballanced and didn't have any problems. Obviously the proper way is to have it ballanced. I'm sure I just got lucky.
How fast did you drive the car wit hthat unbalanced shaft ? The only time I ever had it done the balance seemed ok at the legal speed limit , 100mph with a 3.23 gear and a 4 speed was a completely different matter .
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Re: Shortening a driveshaft yourself
[Re: JohnRR]
#1111412
11/11/11 07:01 PM
11/11/11 07:01 PM
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Joined: May 2003
Posts: 15,487
Florida
scratchnfotraction
I Live Here
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I Live Here
Joined: May 2003
Posts: 15,487
Florida
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Quote:
Quote:
I had a driveshaft shortened at a metal fab shop once. What you described is exactly what they did. I never had it ballanced and didn't have any problems. Obviously the proper way is to have it ballanced. I'm sure I just got lucky.
How fast did you drive the car wit hthat unbalanced shaft ? The only time I ever had it done the balance seemed ok at the legal speed limit , 100mph with a 3.23 gear and a 4 speed was a completely different matter .
this is not a place to cut corners. IMHO
ever have a shaft come out at trip diget speeds 
you need a least a lathe,then mill the weld bead only to remove the yoke,make the tube cut with the lathe also,then replace the yoke and phase it back to the other end,reweld it,only way i know to get it straight..then have a high speed balance to check the run out.
my local machine shop chops them down 25$ but i have to go to the drive shaft shop for balance at another 40$
$ well spent in my book
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Re: Shortening a driveshaft yourself
[Re: Challenger 1]
#1111414
11/11/11 07:10 PM
11/11/11 07:10 PM
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Joined: Jan 2007
Posts: 1,169
MI
68shifter
super stock
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super stock
Joined: Jan 2007
Posts: 1,169
MI
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I have done hundreds with a dial indicator, a home made jig to roll everything, and checking and rechecking. Most shafts pull loads of 250k along with multiple car shafts. Never has one come back. The lathe makes cleaning the weld off easier but some time and a cut off wheel will work too. Quality and consistency of the weld is very important to the balance, I have seen slot of shafts need balanced just because of how some idiot welded them.  Good luck, be safe with it.
68' Barracuda (4 speed)
64' Savoy (4 speed)
65' Satellite (girl tranny)
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Re: Shortening a driveshaft yourself
[Re: Challenger 1]
#1111417
11/11/11 07:13 PM
11/11/11 07:13 PM
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Joined: May 2003
Posts: 15,487
Florida
scratchnfotraction
I Live Here
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I Live Here
Joined: May 2003
Posts: 15,487
Florida
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doing it and getting away with it and doing it right are 2 diff things. the yokes have to be phased the end welds need milled not cut with a hacksaw needs a dail indicator to make sure it straight on the run out yes you could be close to the balance it once had,but it has now changed with the cut and reweld bead all this will make the u-joint have a longer service life,and stay in the car at high speeds I have hacked shafts up and even welded u-joint caps into yokes after grinding the yokes to get them to angle more with out binding on a lot of 4x4 junk. after throwing one at 105 mph on I-75 in a 73 duster, i wont ever skimp on a shaft again. not saying you cant do it and get away with it..but it can bite back at ya
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Re: Shortening a driveshaft yourself
[Re: scratchnfotraction]
#1111418
11/11/11 07:24 PM
11/11/11 07:24 PM
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Joined: Oct 2003
Posts: 21,345
Marysville, O-H-I-O
70Cuda383
Too Many Posts
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Too Many Posts
Joined: Oct 2003
Posts: 21,345
Marysville, O-H-I-O
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unless you have some REALLY good equipment at home, I wouldn't even chance it.
$300 to build a whole new driveshaft, or $100 to cut one down and rebalance it at just about any local clutch/driveline shop seems like small change when you're spending thousands on a car and it's drivetrain.
**Photobucket sucks**
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Re: Shortening a driveshaft yourself
[Re: VITC_GTX]
#1111419
11/11/11 08:05 PM
11/11/11 08:05 PM
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Joined: Jan 2003
Posts: 25,726
Rio Linda, CA
John_Kunkel
Too Many Posts
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Too Many Posts
Joined: Jan 2003
Posts: 25,726
Rio Linda, CA
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The reality is that most driveshaft tubing isn't all that round so dial indicating is useless and the method of separating the tubing end is irrelevant as long as the end is reinstalled in phase and equidistant with the other.
The INTERNET, the MISinformation superhighway
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Re: Shortening a driveshaft yourself
[Re: VITC_GTX]
#1111422
11/12/11 08:24 AM
11/12/11 08:24 AM
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Joined: Jan 2003
Posts: 20,158
Park Forest, IL
slantzilla
Too Many Posts
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Too Many Posts
Joined: Jan 2003
Posts: 20,158
Park Forest, IL
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We did a couple in my buddy's home shop many years ago with a small metal band saw and a stick welder, cutting the factory weld with a hack saw.
Scribe a line on the shaft and yoke and you can get it back in the right position.
Biggest problem we ran into was that some shafts had an inner tube that was a real PITA to cut down.
Never had one break, and one was in a pig block 4 speed car.
We did them ourselves mainly because there wasn't a driveline shop within 50 miles of us.
"Everybody funny, now you funny too."
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Re: Shortening a driveshaft yourself
[Re: slantzilla]
#1111423
11/12/11 09:50 AM
11/12/11 09:50 AM
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Joined: Mar 2005
Posts: 1,445
Sterling Heights, Michigan 483...
daniel_depetro
pro stock
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pro stock
Joined: Mar 2005
Posts: 1,445
Sterling Heights, Michigan 483...
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I've done a few myself and must have got lucky.  I simply scribed a lineup mark on the shaft/end and cut through the weld with a cut off tool. I then cut the driveshaft the desired amount. On the last shaft that I cut I also had to relocate the attached weight. I grinded down the weld smooth with a standard 4.5" hand held grinder. Is it precise? No. Is it perfectly balanced? No. Can I feel any vibrations or any other adverse effects? No. Does it work for me? Yes. This is my personal experience and opinion. Take it for what it;s worth. It plus $1.10 will get you a cup of coffee.
1969 Dodge Super Bee A12 (440 Six Pack, 4-speed, Dana 60 4.10)
1972 Plymouth Road Runner (400, 4-speed, 8.75" 3.23)
1974 Plymouth Duster 360 (360, 4-speed, 8.75" 3.23)
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Re: Shortening a driveshaft yourself
[Re: Finoke]
#1111425
11/12/11 10:46 AM
11/12/11 10:46 AM
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Joined: Jan 2003
Posts: 74,942
U.S.S.A.
JohnRR
I Win
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I Win
Joined: Jan 2003
Posts: 74,942
U.S.S.A.
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Quote:
Has anyone tried this driveshaft kit? I've been thinking of doing that for my small to big block conversion.
Driveshaft kit from Mancini's
That was never balanced to begin with so I doubt it would even be close ...
But it seems the overwhelming response is to just weld it up an go ...
I guess we can put driveline shops right up there with automotive machine shops , balancing is just another money grab ...
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Re: Shortening a driveshaft yourself
[Re: JohnRR]
#1111427
11/12/11 11:04 AM
11/12/11 11:04 AM
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Joined: Dec 2007
Posts: 587
minot north dakota
ledft79
mopar
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mopar
Joined: Dec 2007
Posts: 587
minot north dakota
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I had a welding shop cut the shaft on my 70 cuda, when I switched from a 318 to a 440. That was back when I was a kid and drove like nothing else mattered. It was topped out and close to topped out many times, and I don't remember there being any vibration at all. Lathe or no lathe, I don't know.
DRIVE EM, DONT HIDE EM.
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