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Old 12-28-2018, 12:47 PM
70Newport 70Newport is offline
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Default Pandora's box (drivetrain geometry)

Not sure where to put this thread so I put it here.

After reading numerous articles I cant determine what to believe.

I have landed on using a ford 8.8" rear end. My plan is to shorten the drivers side of the axle to center the pumpkin and this will leave the pinion approximately an inch off center. I would rather not offset my engine and trans. Is this going to be a problem or not. I have read "make it all a straight line" and I have read "thats what U joints are for"

Thanks!
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Old 12-28-2018, 01:19 PM
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I have always been told that it's harder on a u joint to run it straight than with some angle to it. All of my sedans have been centered motor and trans and offset 9" rear axles. No problems. The a.d. chevys I have build use 8.8s and I've never had any issues. The joints in my truck are going on 6 plus years.
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Old 12-28-2018, 01:51 PM
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eyesore eyesore is offline
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I ran a SBC with a stock 8.8" no problem!

iSore
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Old 12-28-2018, 01:52 PM
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Dr Crankenstein Dr Crankenstein is online now
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U joints need some working angle in order to "cycle", wear evenly and keep themselves lubricated.

Offset pinions have worked successfully since forever. There's no need to center it, unless you have a very short wheelbase... or severe joint angles you can't defeat otherwise.

I keep this document on file. Everything you ever wanted to know (and more) is in there. It's too big to upload here, so I have to post a link...

http://media.spicerparts.com/cfs/fil...store=original

.
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Old 12-28-2018, 02:47 PM
70Newport 70Newport is offline
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Awesome thanks everyone for your input. Im going to center the housing and run the offset pinion with the motor and trans centered. Starting to mock things up this weekend finally so I can make some progress hopefully. Ill be starting a build thread soon!.

Thanks again!
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Old 12-28-2018, 02:53 PM
70Newport 70Newport is offline
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Quote:
Originally Posted by Dr Crankenstein View Post
U joints need some working angle in order to "cycle", wear evenly and keep themselves lubricated.

Offset pinions have worked successfully since forever. There's no need to center it, unless you have a very short wheelbase... or severe joint angles you can't defeat otherwise.

I keep this document on file. Everything you ever wanted to know (and more) is in there. It's too big to upload here, so I have to post a link...

http://media.spicerparts.com/cfs/fil...store=original

.
Great article!
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  #7  
Old 12-29-2018, 11:29 PM
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70, I have two bits of advice. First, Listen to Dr. C. and the second, make sure your motor/ transmission shafts are parallel to the pinion shaft, both horizontally and vertically. That makes the working angles of the front U-joint and the rear one equal, horizontally and vertically.
If you line up a string from underneath the front of your motor, [centre of the crankshaft] past the back of the transmission, [centre of the output shaft] to the rear axle, and another string lined up exactly with the pinion shaft, the two strings should be parallel front to rear.
I have done this but not tested it as it is really winter here.
Good Luck.
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