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10sec.et Member

Joined: 29 Mar 2006 Posts: 3483 Location: Houston,Texas 347040.52 points
1969 Oldsmobile Cutlass
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Posted: Mon Apr 30, 2007 11:22 pm Post subject: driveshaft angle |
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i finally finished welding my housing (pics coming soon) and did a quick mock-up to see how it fit in the car. the driveshaft has the wrong angle when the diff is at the height i want it to be (see attatched sketch). i dont want the car to sit high like some weird 4X4 but i doubt the current angle of the driveshaft will work either. the best i can think of is to raise the trans and lower the diff housing to split the difference. any better ideas ? i assume the angle on the trans should be the same as the diff.
BTW the sketch is exaggerated for illustration purposes.
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af2 wrote: | It seems we can look at our magical Balls and come up with a fix?
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nwcc Member

Joined: 11 Aug 2005 Posts: 453 Location: Pacific Northwest 158.80 points
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Posted: Tue May 01, 2007 12:51 am Post subject: Re: driveshaft angle |
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10sec.et wrote: | the best i can think of is to raise the trans and lower the diff housing to split the difference. any better ideas ? i assume the angle on the trans should be the same as the diff.
BTW the sketch is exaggerated for illustration purposes. |
Are you using the stock style control arm rear suspension?
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10sec.et Member

Joined: 29 Mar 2006 Posts: 3483 Location: Houston,Texas 347040.52 points
1969 Oldsmobile Cutlass
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Posted: Tue May 01, 2007 7:26 am Post subject: |
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no, it was too much trouble to put the factory suspension back on so i went with ladder bars.
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af2 wrote: | It seems we can look at our magical Balls and come up with a fix?
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beersngars Member

Joined: 04 Feb 2006 Posts: 390 Location: Ohio 13369.80 points
1948 Chevrolet Coupe
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Posted: Tue May 01, 2007 8:18 am Post subject: |
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Are the ladder bars not adjustable??
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10sec.et Member

Joined: 29 Mar 2006 Posts: 3483 Location: Houston,Texas 347040.52 points
1969 Oldsmobile Cutlass
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Posted: Tue May 01, 2007 8:26 am Post subject: |
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yeah, they are adjustable. i havent mounted the ladder bar crossmember yet either. im just loking for suggestions for the best way to go about setting all of this up.
if the trans yoke is lower than the diff yoke, wouldnt that be backwards on the angles ? or does it matter ?
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af2 wrote: | It seems we can look at our magical Balls and come up with a fix?
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beersngars Member

Joined: 04 Feb 2006 Posts: 390 Location: Ohio 13369.80 points
1948 Chevrolet Coupe
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Posted: Tue May 01, 2007 8:43 am Post subject: |
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I would think the diff would have to be lower but not sure. I do know you want the ladder bar parallel to the ground at ride height. That should give you an idea where the cross member goes. Can the trans go up?
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10sec.et Member

Joined: 29 Mar 2006 Posts: 3483 Location: Houston,Texas 347040.52 points
1969 Oldsmobile Cutlass
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Posted: Tue May 01, 2007 9:26 am Post subject: |
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the trans can go up about an inch. i may just have to live with the fact that the car will need to sit higher in the rear .
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af2 wrote: | It seems we can look at our magical Balls and come up with a fix?
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nwcc Member

Joined: 11 Aug 2005 Posts: 453 Location: Pacific Northwest 158.80 points
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Posted: Tue May 01, 2007 10:35 am Post subject: |
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10sec.et wrote: |
if the trans yoke is lower than the diff yoke, wouldnt that be backwards on the angles ? or does it matter ? |
Whats the angle of the axle yoke?
Most ladder bar instructions that I have read say to set the axle yoke -2 to -3 degree's at installed height. Are you outside of that spec? What did the instructions with your ladder bars direct you to do?
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10sec.et Member

Joined: 29 Mar 2006 Posts: 3483 Location: Houston,Texas 347040.52 points
1969 Oldsmobile Cutlass
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Posted: Tue May 01, 2007 11:03 am Post subject: |
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i dont have a problem getting the diff yoke to that spec, the problem is my ride height causing the angles you see in the diagram. i wanted the car to sit level but with 30 inch tall tires its a bit of a challenge getting the driveline correct. seeems to me that the trans and diff should have opposite angles.
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af2 wrote: | It seems we can look at our magical Balls and come up with a fix?
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nwcc Member

Joined: 11 Aug 2005 Posts: 453 Location: Pacific Northwest 158.80 points
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Posted: Tue May 01, 2007 11:36 am Post subject: |
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After reading your post I went out an checked the angle of my transmission tailshaft. Its -2 so I'm in a similar situation as you. I'd bet that most cars are this way.
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af2 Member

Joined: 01 Sep 2003 Posts: 5579 Location: grassvalley, ca 71896.24 points
1933 Willys Coupe
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Posted: Tue May 01, 2007 1:34 pm Post subject: |
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10, if the trans is pointing down you want the axle pointing up to make a straight plain and allow the U-joints to work together instead of against each other.
Hope you understand what I am trying to say.
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nwcc Member

Joined: 11 Aug 2005 Posts: 453 Location: Pacific Northwest 158.80 points
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Posted: Tue May 01, 2007 1:48 pm Post subject: |
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Welcome back AF2
Did you get some R&R?
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10sec.et Member

Joined: 29 Mar 2006 Posts: 3483 Location: Houston,Texas 347040.52 points
1969 Oldsmobile Cutlass
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Posted: Tue May 01, 2007 2:21 pm Post subject: |
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good to see you back. how was the vacation? at least thats where i assume you went.
oh, back on topic, i found this article....http://www.carcraft.com/howto/91758/. af2, i understood what youre saying and its the "straight line" part that makes me believe i need to get the diff a bit lower because the way it is now, if i raise the pinion angle opposite of the trans, theres no way possible it could make a straight line through the drivetrain with the pinion pointing up.
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af2 wrote: | It seems we can look at our magical Balls and come up with a fix?
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af2 Member

Joined: 01 Sep 2003 Posts: 5579 Location: grassvalley, ca 71896.24 points
1933 Willys Coupe
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Posted: Tue May 01, 2007 2:29 pm Post subject: |
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10sec.et wrote: | good to see you back. how was the vacation? at least thats where i assume you went.
oh, back on topic, i found this article....http://www.carcraft.com/howto/91758/. af2, i understood what youre saying and its the "straight line" part that makes me believe i need to get the diff a bit lower because the way it is now, if i raise the pinion angle opposite of the trans, theres no way possible it could make a straight line through the drivetrain with the pinion pointing up. |
That bottom picture on that page is what I was saying.
Vacation was great! All of us stayed out of the Mexican jail and caught some big Dorado and Marlin. Nothing like the Caribbean in April!
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beersngars Member

Joined: 04 Feb 2006 Posts: 390 Location: Ohio 13369.80 points
1948 Chevrolet Coupe
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Posted: Tue May 01, 2007 2:33 pm Post subject: |
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If you scroll down about half way thru the CarCraft article, there is a diagram that makes it easy to see what Adam is talking about. Below it states "Ideally, the angles between the transmission output shaft and driveshaft, and between the driveshaft and the pinion will be equal and opposite." Thats the the old rule of thumb formula. Most of the time the trans angle is somewhat fixed and the pinion angle is the "experimental" angle. You'll know if it's wrong the first time out.
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