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Off-set Pinion Shaft

2K views 25 replies 11 participants last post by  enjenjo 
#1 ·
In the process of aligning my '96 LT1 engine/4L60E tranny with the rear-end ('02 Camaro Limited Slip) for a 1937 Chrysler rod I am building, I just discovered the Pinion shaft is not in the exact center of the rear-end housing. It is off-set to the passenger side about 3/4". Is the best way to move the engine over the same amount (which creates some other space problems for me); or **** the engine in the frame ever so slightly? Does anyone know how the folks at GM handles this problem? Not having the engine square in the frame is my best solution.
 
#2 ·
dchatcher said:
Is the best way to move the engine over the same amount (which creates some other space problems for me); or **** the engine in the frame ever so slightly?
You do not want to slant the engine (can't say **** "kock"?!? lol) in the chassis. Move either it or the rear end to keep it at 90 degrees.

To do otherwise is an invitation to epic driveline vibration and short U-joint life.

Bummer, I know. :pain:
 
#4 ·
The trans yoke and pinion yoke must be in perfect alignment or you'll have vibration and eventually worn broken parts and alot sooner than you want. The u-joints are intended to run out of plane in a single direction (up and down) if it tries to run in two it will make an eliptical pattern not circular.
 
#5 ·
i adree with everyone above, and this is the excepted method or way of thinking.

B U T...
just food for thought, EVERY corvette from 63 to 82 has the engine offset 1 1/2 inches, the trans centered and the rear centered. they don't have undue vibration or u joint problems. the factory built them all this way. :D :welcome:
 
#7 ·
In the Corvette the diff center was in a fixed location that did not move up and down that way they could offset the pinion location, still the u-joint can only operate out of plane in a single direction that's why front wheel drive cars use constant velocity joints. If you don't believe me mock every thing up before you weld anything and try to spin the driveshaft then you'll see what I'm talking about.
 
#9 ·
dchatcher said:
In the process of aligning my '96 LT1 engine/4L60E tranny with the rear-end ('02 Camaro Limited Slip) for a 1937 Chrysler rod I am building, I just discovered the Pinion shaft is not in the exact center of the rear-end housing. It is off-set to the passenger side about 3/4". Is the best way to move the engine over the same amount (which creates some other space problems for me); or **** the engine in the frame ever so slightly? Does anyone know how the folks at GM handles this problem? Not having the engine square in the frame is my best solution.
Having the pinion shaft offset is quite normal and to be expected. A Ford 9" has about 1 1/4" offset.

You do NOT have to install the engine off to one side. This is sometimes done (even from the factory) for steering clearance, NOT to align the driveshaft.

You should avoid canting the engine. This will definitely cause premature failure of the u-joints.

The correct alignment is for the engine crankshaft centerline and the centerline of the pinion shaft to be parallel to each other. This is when looking from the side and/or from above.
 
#11 ·
red65novawagon said:
The trans yoke and pinion yoke must be in perfect alignment or you'll have vibration and eventually worn broken parts and alot sooner than you want. The u-joints are intended to run out of plane in a single direction (up and down) if it tries to run in two it will make an eliptical pattern not circular.
not insulting you, but just debateing. but how do the u-joints know they are operating a single direction??? (they have no brains). i,m an old retired corvette mechanic and have known about this koked engine deal for decades.i'm restoring my 64. (it'a body off resto mod) and just for fun, i guy who bought a 65 disk brake car.

,m
and i'm working on on a friends 65 vette.
he was freaked out by the offset of the engine. i told him " your car has been wrecked. then I showed him the engine was offset from the factory. go figure, i'm tired. we went fred stokes ranch
 
#12 ·
A u-joint when working at an angle will have fast and slow portions of its rotation, for lack of a better term. The idea is to have these motions in phase w/each other. If there are more than one out of plane angle, it's easy to visualize how there will be problems.

Whether a 'Vette has this "two planes out of phase" is really a moot point. It is not a desirable thing, and I suspect the engineers of the 'Vette did this for reasons that are not usually encountered- and did the things necessary to quell any damaging vibes/oscillations that will result.
 
#13 ·
Most rear drive GM cars have the engine offset to the right. And most of them have a centered pinion. the angle is a non issue. up and down, side to side, or at 45 degrees, as long as the angle of the joint is less than 7 degrees, and equal but opposite the angle on the second joint, there is no problem.
 
#15 ·
If the driveshaft is offset to one side, that would be one angle in a vertical plane. If it's offset up and down that is one angle in a horizintal plane. If it is offset both vertically, and horizontally, it is still one angle, but at 45 degrees to both the vertical, and horizontal, and still measured the same way.
 
#17 · (Edited)
:nono: I've tried to explain this in the simplest posible way but some thing you just can't get across. The pinion has to be square to the out put shaft of the trans looking at it from above PERIOD. The only other way to explain this is look at the front end of GM 1/2 ton 4 wheel drive trucks, they're using CV style drive axles because U-joint simply can't articulate to accommodate two separate planes of motion. If you still don't believe me do it the other way and you'll be doing it twice! I guarantee it!:boxing:
 
#18 ·
red65novawagon said:
:nono: I've tried to explain this in the simplest posible way but some thing you just can't get across. The pinion has to be square to the out put shaft of the trans looking at it from above PERIOD. The only other way to explain this is look at the front end of GM 1/2 ton 4 wheel drive trucks, they're using CV style drive axles because U-joint simply can't articulate to accommodate two separate planes of motion. If you still don't believe me do it the other way and you'll be doing it twice! I guarantee it!:boxing:
It doesn't matter which way the offset is, there is still only one angle. As long as all the major components are parallel, engine, trans, and rear end, in a vertical plane, and within a degree or two of parallel in a horizontal plane, and none of the Ujoint angles are over 7 degrees, it will work fine.
 
#22 ·
red65novawagon said:
Get back to me when you offset it side to side then I'll just tell you I told you so.
I build 5 to 10 cars a year, for the last 40 years. I know what works, what don't work, and why.

Just imagine this, with the pinion centered, and the engine centered, put the whole car on a rotisserie. when you turn the car over, the angle will change from vertical to horizontal, without any relative movement. And it will work just as well at any of the angles in between. The angle doesn't change, just the orentation of the angle changes. It's still one angle.
 
#24 ·
red65novawagon said:
We need to clarify some terms. Pinion offset is a fixed location in the differential housing center section, what everyone is talking about here is pinion centerline and yes the u-joints will accommodate a little variation but not much for long. Peace man :D
Ok, i'll redefine. As long as the Ujoint angles are the same front to rear on a two Ujoint shaft, and the angle in both Ujoints is under 7 degrees, they will function indefinely as designed, quite nicely, with the working angle in any direction, as long as the front and rear working angle is the same, but opposite.
 
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