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0pinion on pinion

Thunderlugs

Thunderlugs

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I need to measure for a new driveshaft in my 65 Bel, 440, late model Torqueflite,8 3/4, 3600lb SS springs. The Car is not yet complete, however , I added up what was missing, and added that amount of weight throughout the car, got her on the ground, and settled it out. My pinion is sitting at 2 1/2 degrees up. My understanding, it ideally should be 3 to 4 degrees down. Is there enough single shim available to correct this? Should I leave it? Not planning on going to the track. Also, do not intend on cutting and re welding the purches. Should this Imperfection be that critical on the length of the driveshaft?
Thanks
Thunder
 
Thunderlugs said:
I need to measure for a new driveshaft in my 65 Bel, 440, late model Torqueflite,8 3/4, 3600lb SS springs. The Car is not yet complete, however , I added up what was missing, and added that amount of weight throughout the car, got her on the ground, and settled it out. My pinion is sitting at 2 1/2 degrees up. My understanding, it ideally should be 3 to 4 degrees down. Is there enough single shim available to correct this? Should I leave it? Not planning on going to the track. Also, do not intend on cutting and re welding the purches. Should this Imperfection be that critical on the length of the driveshaft?
Thanks
Thunder
Click to expand...
There won't be much movement at all, as you suspect. But I would correct that pinion angle. Correct angle allows full horsepower to reach the axle and extends u-joint life.
Mike
 
65affair said:
Remember the pinion angle is in relation to the driveshaft...
Click to expand...
No it is not. It's in relation to the crank centerline. If the crank is 2 1/2 down in back and the pinion 2 1/2 up, that would be zero. Obiviously with leaf springs we would add additional down angle at the pinion. It is entirely possible to have overall measured downward pinion angle with the pinion pointing up from the ground. Mine is definately up.
Doug
 
dvw said:
No it is not. It's in relation to the crank centerline. If the crank is 2 1/2 down in back and the pinion 2 1/2 up, that would be zero. Obiviously with leaf springs we would add additional down angle at the pinion. It is entirely possible to have overall measured downward pinion angle with the pinion pointing up from the ground. Mine is definately up.
Doug
Click to expand...
I will have to disagree, It is the relation between the drive shaft and the pinion, the pinion should be 1-3 degrees nose down to the drive shaft. "According to Currie, the average car crafter should strive for between 1 and 3 degrees between the tailshaft of the transmission and driveshaft, and 1 to 3 degrees between the driveshaft and pinion. Furthermore, the two angles should be nearly equal (between 1 and 3 degrees), but always opposite.
 
DVW is correct. Drive shaft angle really has very little to do with setting pinion angle. Under load, the ideal situation would be Engine/trans angle matched with the pinion angle. At rest, because of axle windup, the pinion angle (nose) should be a couple degrees lower than the engine/trans angle. Maybe more depending on the condition of your leaf springs. That said, When you say your pinion is 2.5 degrees up, I hope you are saying the nose of your pinion is up 2.5 degrees. You have to know the difference in terminology. I know it can be confusing but Nose up means the angle is going down front to rear. Nose down means the angle is going up front to rear. Clear as mud ain't it. The first thing you need to measure is your engine/trans angle. You can put a digital angle finder on the flywheel pulley to get that angle first. If it is 4 degrees down, (front to rear) your pinion angle 2.5 degrees (nose up) might be in the ballpark. Forget about the driveshaft angle. It just confuses the issue further.
 
Easiest way to think about it is the crank/trans C/L and pinion C/l should be parallel under acell. All rear suspension allows some housing upward rotation under load. Depends on the amount of load and type of suspension. For example. Say what is you wanted zero overall angle. And you car had higher ride height or very low engine location. It could have an extreme driveshaft angle. But the two C/Ls could still be parallel resulting in zero overall angle. This is why the driveshaft itself isn't measured. Like I said measure the engine/trans. Then figure what additional angle you would like for your use and suspension. Add the additional angle to the parallel number. Example. Engine trans is 3 degrees down at the back. That means to be parallel the pinion needs to be 3 degrees up. Now we add the angle the housing will rotate. If that number is 1 degree, then the pinion is up 2 degrees. If that number is 3 degrees, then the pinion is zero. If that number is 5 degrees than the pinion would point down 2 degrees. What is a good housing rotation number? Street 1-2, hot rod leaf spring 3-4, race leaf spring 5-7, ladder bar 1-2, 4 link 1-1/2. All these numbers are added to the parallel number of the pinion. This method works and is correct. Its what we used in the dealership on problem vehicles. Its what works on the street. It works at the track.
Doug
 
Dipstick said:
Race car or street car? Stock B-body pinion angle is 4 degrees up.
Click to expand...
This is not the pinion angle. The spring pads are welded on a stock housing pointing the pinion approx 4 -5 degrees up. The leaf spring is not parallel to the ground where the housing is bolted. That mounting surface points down towards the front.
Doug
 
dvw said:
Easiest way to think about it is the crank/trans C/L and pinion C/l should be parallel under acell. All rear suspension allows some housing upward rotation under load. Depends on the amount of load and type of suspension. For example. Say what is you wanted zero overall angle. And you car had higher ride height or very low engine location. It could have an extreme driveshaft angle. But the two C/Ls could still be parallel resulting in zero overall angle. This is why the driveshaft itself isn't measured. Like I said measure the engine/trans. Then figure what additional angle you would like for your use and suspension. Add the additional angle to the parallel number. Example. Engine trans is 3 degrees down at the back. That means to be parallel the pinion needs to be 3 degrees up. Now we add the angle the housing will rotate. If that number is 1 degree, then the pinion is up 2 degrees. If that number is 3 degrees, then the pinion is zero. If that number is 5 degrees than the pinion would point down 2 degrees. What is a good housing rotation number? Street 1-2, hot rod leaf spring 3-4, race leaf spring 5-7, ladder bar 1-2, 4 link 1-1/2. All these numbers are added to the parallel number of the pinion. This method works and is correct. Its what we used in the dealership on problem vehicles. Its what works on the street. It works at the track.
Doug
Click to expand...
Thanks Doug. I'm going to digest this, get the car on the ground, settled out, and check what I have again. I did measure the engine, at the face of the balancer, and on the trans output shaft. I believe it was 1 degree down at the back, and the pinion was pointing 2 1/2 up . I guess I might be better off than I think Got to take this slow..... it can get a bit confusing!
 
Doug is correct. Here is a good show of it as its in the very first part of this. Of course the parallel lines of the eng/trans and rear pinion need to be like that when on the gas pedal. So if its a leaf spring car and you want about 3 degrees down and the trans/eng centerline is 0 then the pinion is set 3 down so when it moves 3 degrees when on the throttle it will be parallel to the eng/trans centerline but not the same centerline. Ron
http://www.moparts.org/Tech/Archive/axle/8.html
 
383man said:
Doug is correct. Here is a good show of it as its in the very first part of this. Of course the parallel lines of the eng/trans and rear pinion need to be like that when on the gas pedal. So if its a leaf spring car and you want about 3 degrees down and the trans/eng centerline is 0 then the pinion is set 3 down so when it moves 3 degrees when on the throttle it will be parallel to the eng/trans centerline but not the same centerline. Ron
http://www.moparts.org/Tech/Archive/axle/8.html
Click to expand...
Thanks Ron! Very informative.
 
dvw said:
Easiest way to think about it is the crank/trans C/L and pinion C/l should be parallel under acell. All rear suspension allows some housing upward rotation under load. Depends on the amount of load and type of suspension. For example. Say what is you wanted zero overall angle. And you car had higher ride height or very low engine location. It could have an extreme driveshaft angle. But the two C/Ls could still be parallel resulting in zero overall angle. This is why the driveshaft itself isn't measured. Like I said measure the engine/trans. Then figure what additional angle you would like for your use and suspension. Add the additional angle to the parallel number. Example. Engine trans is 3 degrees down at the back. That means to be parallel the pinion needs to be 3 degrees up. Now we add the angle the housing will rotate. If that number is 1 degree, then the pinion is up 2 degrees. If that number is 3 degrees, then the pinion is zero. If that number is 5 degrees than the pinion would point down 2 degrees. What is a good housing rotation number? Street 1-2, hot rod leaf spring 3-4, race leaf spring 5-7, ladder bar 1-2, 4 link 1-1/2. All these numbers are added to the parallel number of the pinion. This method works and is correct. Its what we used in the dealership on problem vehicles. Its what works on the street. It works at the track.
Doug
Click to expand...
In this example , is the pinion flange pointing up or down , for clarification, please! In my situation, 67 Gtx 440 4/s car engine angle 2.3/4 degrees,down to rear,and pinion angle , level car zero degrees , near 500 hp , your calculation
 
Last edited:
You have a PM
Doug
 
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