Pinion angle question

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RustyRatRod said:
No you never did it right side up. At least not that you pictured. Either way will get it done.
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No I didnt picture it but I did it both ways up and down to check my work and got two different readings. I leveled the blocks and set the flats of the arch on it and got like 6 degrees the flipped it around to double check and got like 8 or 9. That's what's pictured. That's why I am so confused how I get two different readings it should be the same up or down
 
RustyRatRod said:
You know that and I do too, but it would be easier for him to LEARN it that way. Or so I thought. He's still not done it that way yet.....and he thinks he has. lol
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That's what I said to begin with lol when the rearend was still in the car. The perches was at 6 degrees I could add that to the 6 to the 5 and weld it at 11 and be dead on.
 
dartfreak75 said:
No I didnt picture it but I did it both ways up and down to check my work and got two different readings. I leveled the blocks and set the flats of the arch on it and got like 6 degrees the flipped it around to double check and got like 8 or 9. That's what's pictured. That's why I am so confused how I get two different readings it should be the same up or down
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If you'll just throw the original rear axle in the ditch and do it like Cass said, you'll be dead on. That's how I tried to tell you originally and all these cats came in and said I was wrong. I am not. They are getting working angle and pinion angle confused. I've done this type work a very long time.
 
dartfreak75 said:
No I didnt picture it but I did it both ways up and down to check my work and got two different readings. I leveled the blocks and set the flats of the arch on it and got like 6 degrees the flipped it around to double check and got like 8 or 9. That's what's pictured. That's why I am so confused how I get two different readings it should be the same up or down
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The difference might be because your pinion may be rotating either way between measurements. If you look at the picture of the pinion measurement, I can't tell if the angle finder (and yoke saddle) are plumb. Are they? Make sure it is so you can get repeatable measurements.
 
dartfreak75 said:
I just drew it out and I'm backwards. If the perches are level and the pinion is at 5 degrees then you put the pinion level the rear of the perches would go up! Right now my perches are at 6 degrees with the back down so I I need to set the pinion at 11 degrees. 6 to level the perches and 5 to get my pinion angle. Correct?
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See I said that here haha
 
dartfreak75 said:
That's what I said to begin with lol when the rearend was still in the car. The perches was at 6 degrees I could add that to the 6 to the 5 and weld it at 11 and be dead on.
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But all "I" understood was the way I tried to tell you to do it. I couldn't (and still cannot) make sense of adding this to that. It's either 5* nose up or not. lol That's how my mind works.
 
RustyRatRod said:
But all "I" understood was the way I tried to tell you to do it. I couldn't (and still cannot) make sense of adding this to that. It's either 5* nose up or not. lol That's how my mind works.
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I get that. It's all good its better to be safe than sorry! And I completely understand why everyone says the 5 degree down thing! Its because they are welding the perches from the top. So the rear is upside down. So it is 5 degrees down. So when you flip it back over its actually 5 degrees up. See I'm learning! Haha I get it now I completely understand it. I just dont understand why I'm getting different readings I'm gonna try it again tomorrow when it's not pouring rain and see what I can get but I think I'm just gonna weld it at 5 and call it done.
 
Ok problem solved! My angle finder is fubar! I measured twice again on my original rearend got the same as yesterday. So with the tool still attached I started twisting the axle. I moved it a good three inches and the needle never moved at all. So I guess I will buy a new one and start over. I got the new rear set up on blocks and tried it and I get two different readings on the pinion without moving the pinion at all. I can move it from one way and flip it around and get 6 degrees difference without moving anything.
 
dartfreak75 said:
Ok problem solved! My angle finder is fubar! I measured twice again on my original rearend got the same as yesterday. So with the tool still attached I started twisting the axle. I moved it a good three inches and the needle never moved at all. So I guess I will buy a new one and start over. I got the new rear set up on blocks and tried it and I get two different readings on the pinion without moving the pinion at all. I can move it from one way and flip it around and get 6 degrees difference without moving anything.
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They make really good angle finder apps for your smart phone if you have one.
 
dartfreak75 said:
I get that. It's all good its better to be safe than sorry! And I completely understand why everyone says the 5 degree down thing! Its because they are welding the perches from the top. So the rear is upside down. So it is 5 degrees down. So when you flip it back over its actually 5 degrees up. See I'm learning! Haha I get it now I completely understand it. I just dont understand why I'm getting different readings I'm gonna try it again tomorrow when it's not pouring rain and see what I can get but I think I'm just gonna weld it at 5 and call it done.
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No, that's not why. But just get the pinion 5* up from the perches and it'll be right.
 
This is why it's NOSE DOWN. Not because people flip the rear end over, but because the pinion is NOSE DOWN in relation to the transmission output shaft angle like I've said now at least three times. Look at the pictures below. In the incorrect picture, the pinion center line is pointing UP to the transmission output shaft. This is incorrect, since it puts no load whatsoever on the u joints. They must have an angle in order to function. This is called the working angle. Although the pinion angle does point the pinion center line UP about 5*, Once in the car, it should be NOSE DOWN in relation to the transmission output shaft....even though usually, the pinion center line actually points UP. It is the transmission output shaft that it must be parallel to not in line with. Study the pictures.

NOSE DOWN.jpg
 
RustyRatRod said:
This is why it's NOSE DOWN. Not because people flip the rear end over, but because the pinion is NOSE DOWN in relation to the transmission output shaft angle like I've said now at least three times. Look at the pictures below. In the incorrect picture, the pinion center line is pointing UP to the transmission output shaft. This is incorrect, since it puts no load whatsoever on the u joints. They must have an angle in order to function. This is called the working angle. Although the pinion angle does point the pinion center line UP about 5*, Once in the car, it should be NOSE DOWN in relation to the transmission output shaft....even though usually, the pinion center line actually points UP. It is the transmission output shaft that it must be parallel to not in line with. Study the pictures.

View attachment 1715524947
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Yes I understand that I don't think you are understanding what I'm saying lol. It's all good tho I got it done.
 
mopowers said:
Good looking rearend!
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Thanks I still gotta paint the cover and weld on some tabs for the brakes hoses I figured I'd do that when its in the car so I know exactly where to put them. I figured I better not put the hoses on while I'm pulling lifting and tugging on it lol
 
RustyRatRod said:
It's entirely possible. LOL
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Lol what I ment by the 5 down [people saying in the 8.8 thread] is if you weld the perches facing up and level then the rearend is upside down so when you flip it back over its really 5 up. So when your mocking it up you are measuring it 5 down but your working upside down so when you put it in the car its 5 up which is correct. I did like mopowers said and down loaded an app and got like 5.8-6.2 on my original one. Do I set it at 6 and called it good. I actually dug out my other angle finder and got it it says 5. So I'm sending it. Lol
 
dartfreak75 said:
Lol what I ment by the 5 down [people saying in the 8.8 thread] is if you weld the perches facing up and level then the rearend is upside down so when you flip it back over its really 5 up. So when your mocking it up you are measuring it 5 down but your working upside down so when you put it in the car its 5 up which is correct. I did like mopowers said and down loaded an app and got like 5.8-6.2 on my original one. Do I set it at 6 and called it good. I actually dug out my other angle finder and got it it says 5. So I'm sending it. Lol
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I know that's what you meant. But that's not why the industry calls it 5* nose down. Unless you know that, you can get it "all kinda" wrong. 5* was what was recommended a long time ago. Couldda been done by now. LOL
 
RustyRatRod said:
I know that's what you meant. But that's not why the industry calls it 5* nose down. Unless you know that, you can get it "all kinda" wrong. 5* was what was recommended a long time ago. Couldda been done by now. LOL
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I wasnt referring to the industry. Lol it's done! :thumbsup:

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mopowers said:
I'd wait till you have the engine and trans in the car. That way you can set the pinion angle relative to the output shaft of the transmission and not an arbitrary number that may get you close, but may also not.
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How could you set the pinion angle with the eng/trans not in the car? The pinion angle is relative to the crankshaft/trans output shaft plane.
 
SpeedThrills said:
How could you set the pinion angle with the eng/trans not in the car? The pinion angle is relative to the crankshaft/trans output shaft plane.
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I measured the pinion angle of the old rearend and set the new one the same
 
SpeedThrills said:
How could you set the pinion angle with the eng/trans not in the car? The pinion angle is relative to the crankshaft/trans output shaft plane.
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He simply set his rearend to stock specs. That's good enough for what he's doing. The factory didn't set pinion angle in the car on each one they built.
 
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