Driveline angles....how to measure??

mrvette

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'72 vette 350 engine, 200 4r trans stock drive shaft/diffy....

so question is, how to measure the drive shaft angles?? kind of hard to do the diffy end, I expect, much less I confused what gear and HOW to do the trans end....the cross support is modified quite a bit so unsure of the height of it in the center, I think the trans mount makes the shaft quite a bit higher, but unsure of how much

I hear the input and output shafts have to be the same angle ...

:twitch:
 

rtj

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Magnetic Digital Angle Gauge from HF is what I used. With the drive shaft out, just used the yoke as my reference surface on pinion and trans.
 

BBShark

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ENGINE: To measure the engine, put a gauge on the engine (like the valve cover or something parallel to the crank).

DRIVESHAFT: Put a gauge on the driveshaft.

DIFFERENTIAL: You should be able to find some "ears" on the diff case that were machined when they machined cover mount surface. These are inline with the output yokes. They are small but if you put a scale on that and a gauge, you can measure the angle.

I just went through this a couple of months ago. I'm interested in what you find.
 

mrvette

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OK, so you saying there is a machines surface on the rear of the main case, where that cover with ears/mounts is attached??

so then another silly question.....if the car is setting in a garage, and the floor is not level front to back, let along side to side, mine has a slope to the door, and the left side of the door/car is also downhill slightly for drainage....

so I ASSume measure X angle , and even with jack under the spring center in back, so I can get under the car....it measures X at the trans, and Y at the diffy, so to ignore the slope with regard to true vertical, which is what the gauges will be revealing.....say I using a metal rule with a bubble float on it, like used in old crude machining work....adjustable square?? so it's the differential between the two I interested in?? they have to match up....so how do I know which way to adjust diffy or trans??

:bonkers:
 

rtj

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OK, so you saying there is a machines surface on the rear of the main case, where that cover with ears/mounts is attached??

so then another silly question.....if the car is setting in a garage, and the floor is not level front to back, let along side to side, mine has a slope to the door, and the left side of the door/car is also downhill slightly for drainage....

so I ASSume measure X angle , and even with jack under the spring center in back, so I can get under the car....it measures X at the trans, and Y at the diffy, so to ignore the slope with regard to true vertical, which is what the gauges will be revealing.....say I using a metal rule with a bubble float on it, like used in old crude machining work....adjustable square?? so it's the differential between the two I interested in?? they have to match up....so how do I know which way to adjust diffy or trans??

:bonkers:

The bolting face of the pinion yoke and trans yoke are perpendicular to centerline of rotation. But require driveshaft removal for access.

I don't think bubble levels would be sufficiently accurate.

Change the pinion angle by tightening or loosening the bolt to the frame under the pinion, this might require shimming the rubber bushing. They should be close unless the frame is damaged.
 

BBShark

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I have my diff rotated CCW (looking at drivers side of car) with the pinion down 1.8 degrees from horizontal

The driveshaft is rotated CW .5 degrees (up at the tailshaft). So if you measure the angle between the two, the angle is 180-1.8-.5 = 177.7

The engine is rotated down CW (at the tailshaft) 2.8 degrees from horizontal. So the angle between the engine and driveshaft is 180-2.8+.5 = 177.7

Also there is about a 1 degree side to side offset between the tailshaft and the pinion.

I measure an original 71 Corvette and found that the driveshaft is basically horizontal with the frame rails. Which means the diff is probably close to horizontal.
 

84rzv500r

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Spicer puts out a great manual on simple and compound drive line configurations

http://spicerparts.com/videos/measuring-driveline-operating-angles

This is this the one I used when I stuffed the 8V-71 and RTO-9513 in my 72GMC 4x6

http://media.spicerparts.com/cfs/files/media/R43pySn3ew5wA2BHs/tcfp0088.pdf

oh and i put 3 degrees more negative with a thicker aluminum spacer at pinion mount (roughly as unless you completely solid mount the diff and brace it moves like a hula dancer) and stabilized/preload it with custom traction bars... Wheel hop gone...
 
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