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Projects pinion Angle??

Discussion in 'Traditional Hot Rods' started by Bryce Livingston, Feb 1, 2016.

  1. Bryce Livingston
    Joined: Oct 24, 2015
    Posts: 6

    Bryce Livingston

    Hi, I am putting a new axle under my Chevy apache and I was wondering if there is a way I could get the correct pinion angle with out the motor and tranny set.
     
  2. dirt t
    Joined: Mar 20, 2007
    Posts: 4,604

    dirt t
    ALLIANCE MEMBER
    from Kingman,AZ
    1. HAMB Old Farts' Club

    Measure the angle of the output shaft on transmission (with the truck at ride height) lets say 3* down angle the Pinion should be 3* up angle.
     
  3. 29moonshine
    Joined: Dec 30, 2006
    Posts: 1,292

    29moonshine
    Member

    if you have the old axle . set the pads on some 4x4 and check the angle on it. then do the same with the new one it will get you close.
     
    mrhp likes this.
  4. atch
    Joined: Sep 3, 2002
    Posts: 4,443

    atch
    Member

    no

    per the original post the engine/trans aren't installed yet...
     
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  5. alchemy
    Joined: Sep 27, 2002
    Posts: 15,521

    alchemy
    ALLIANCE MEMBER

    You can set the rearend's pinion at whatever you want it to be. The catch is you then need to set the engine/trans at the same angle, inversely. :eek:

    Hopefully you have the patience to do the engine/trans first and the rearend later. Maybe just tack-weld the rearend brackets for now so you can move them later?
     
  6. Budget36
    Joined: Nov 29, 2014
    Posts: 3,467

    Budget36
    Member

    Do you have the original rear end?

    I recall when I swapped my 59 rear for a D44, I leveled the Yoke on the rear, then checked the mounts and found that both at 10 degrees...assumed it was done at the factory that way...so tacked them in, installed the rear, once the springs settles back, I was up about 2 degrees!...lol...blew my mind.

    Anyways, if you have the factory rear, match'em, you'll be good:)
     
  7. squirrel
    Joined: Sep 23, 2004
    Posts: 46,135

    squirrel
    Member

    yeah, match the original rear. If not, and you plan on installing the engine so it's how they were originally, put the pinion so it's about 3 degrees "nose up" relative to the frame (with some weight on the springs). then it should be ok. The stock engine angle is about 3.5 degrees
     
  8. models916
    Joined: Apr 19, 2012
    Posts: 380

    models916
    Member

  9. Hotrodhog
    Joined: Aug 11, 2011
    Posts: 169

    Hotrodhog
    Member

    Actually you don't want to match the angle perfectly, if you do, the U joints won't move enough to lube the needle bearings. you will prematurely wear them out. if the engine is 3-5 degrees down as normal, set the rear at 0 degrees. the 3 degree diff will make sure the U joints move enough to lube them and if you step on the gas, the rear will probably move about 3 degrees up from suspension wrap up from the torque and the drive shaft will be straight as an arrow for maximum power transmission.....
     
  10. rustang
    Joined: Sep 10, 2009
    Posts: 710

    rustang
    Member

    Just set up the rear, and tack your brackets in... then once you get the motor/trans installed and everything loaded, cut the tacks, set your pinion and then pull out the rear to weld it all up.
     
  11. alchemy
    Joined: Sep 27, 2002
    Posts: 15,521

    alchemy
    ALLIANCE MEMBER

    Sorry bud, but this is wrong.

    The 3 degree (or whatever degree he needs) up on the rear and the 3 degree down on the transmission are the difference the driveshaft needs to "work" the grease. Any less than that and you get a straight pass-through type situation. But never do you want to have one end different that the other. They need to cancel each other out.

    The only time a car should have the pinion set a bit lower is if it has weak rear parallel leafs that will wrap on launch. On a drag car only! Most street cars will spend most of their life at 65 MPH on the highway, and there won't be any spring wrap during that time. So the driveshaft should be set up to live it's life at the happy place of equal angles front and back.
     
  12. 51box
    Joined: Aug 31, 2005
    Posts: 885

    51box
    Member
    from MA

    I always put the rear down a couple degrees, remember the pinion tries to climb the ring gear under acceleration. Not saying it's the only way but has worked for me. Never had vibration or premature u-joint failure.
     
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  13. Hnstray
    Joined: Aug 23, 2009
    Posts: 11,471

    Hnstray
    ALLIANCE MEMBER
    from Quincy, IL

    I see this idea often expressed here. Unless you are building a drag car that is accelerating for most of the quarter mile, this doesn't seem to be useful. For normal street driven vehicle, even one driven a bit aggressively, the period of time during acceleration in which the springs/suspension wraps up is small compared to amount of time they are at normal position.

    Say, for example, 10% is under heavy acceleration and 90% is 'normal' driving and light acceleration.......90% of the time the u-joint angles are incorrect and likely causing excess wear and possibly some driveline vibration. The actual degrees of variation, of course has a bearing on much of problem this will be. But if one had a 3* down trans/eng centerline, and also put the pinion down 2*, that's a combined 5* of incorrect angle.

    Ray
     
  14. Hotrodhog
    Joined: Aug 11, 2011
    Posts: 169

    Hotrodhog
    Member

    I've been building cars for 40 yrs this way and never have an issue....checked google to see if I'm full of crap,
    Suspension specialist Dick Miller bases pinion angle settings on horsepower. Miller likes to see 2 degrees of negative pinion angle (relative to the driveshaft) on applications in the 400hp range, 3½ to 4½ degrees in the 500hp to 650hp range, and up to 7 degrees with 700 horses or more. Miller also acknowledges that the greater the pinion angle, the more horsepower the driveline will consume, but it’s a compromise that must be made. Miller notes that these angles are merely guidelines, and each individual combination should be fine-tuned.

    Setting Pinion Angle
    Sometimes corrections need to be made at the front of the vehicle to ensure that the engine and trans are sitting in the proper location. 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
     
  15. 51box
    Joined: Aug 31, 2005
    Posts: 885

    51box
    Member
    from MA

    Is this all assuming the crank CL and pinion CL are on the same plane?
     
  16. Budget36
    Joined: Nov 29, 2014
    Posts: 3,467

    Budget36
    Member

    RE: Miller...I believe he is talking about a racing suspension.
    Re: Currie..what they have said is what has been said before, up on the pinion and down on the tailshaft are opposite and how most street cars are set up.
     
    gimpyshotrods likes this.
  17. squirrel
    Joined: Sep 23, 2004
    Posts: 46,135

    squirrel
    Member

    Even on a street car, when you're cruising at 65, you are applying torque to the rear axle housing, and winding the springs up just a bit. That's why I like to have 1/2 to 1 degree nose down on the pinion, relative to the engine/trans center line. On a go fast car, I'll do 1 to 2 degrees. This is for leaf springs...

    edit: down! not up
     
    Last edited: Feb 2, 2016
    gimpyshotrods likes this.
  18. von Dyck
    Joined: Apr 12, 2007
    Posts: 678

    von Dyck
    Member

    Horsepower (more accurately torque) is but only one part of the equation. How gummy the tires (slicks) and the weight pushing down on them factor into the "pinion angle". If you are setting up an Apache rear, you are likely setting up a trailing torque arm system (unless '58 - '59). Very rigid. Axle housing rotation is between minimal and zero. If you have the original housing to refer to, orient the mounting pads on the replacement rear housing the same as on the original.
     
  19. 51box
    Joined: Aug 31, 2005
    Posts: 885

    51box
    Member
    from MA

    What if the pinion is higher then the tail shaft by say 4"s , what would you do then?
     
  20. Budget36
    Joined: Nov 29, 2014
    Posts: 3,467

    Budget36
    Member

    Drive carefully over speed bumps;)
     
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  21. jimmy six
    Joined: Mar 21, 2006
    Posts: 6,390

    jimmy six
    Member

    After u figure out what angle u want, remember not to over tighten the U-bolt nuts. Yokes have purchase places or the u-joint caps have clips on the inside to center it. Over tightening can egg shape the caps and ruin the bearings. I prefer a locking type nut... Good Luck
     
  22. AmishMike
    Joined: Mar 27, 2014
    Posts: 448

    AmishMike
    Member

    Think I agree with "51box" if I understand what he wrote. Pinion down a little, trans up reverse angle. Even cruising at 65 body goes up/down on bumps & angle changes - body ( engine & trans ) goes up & down while rear stays on the ground ( hopefully ). Come over a bridge in Pa. and usually a bump to flat road ( after spring thaw bumps get bigger). I do drag race almost weekly with about 500 hp (hope) & beat it on street.
     
  23. sport fury
    Joined: Jul 25, 2009
    Posts: 593

    sport fury
    Member

    AKA driveline phasing
     
  24. DdoubleD
    Joined: Nov 18, 2009
    Posts: 221

    DdoubleD
    Member
    from Michigan

    No 2x. If you guess wrong after everything is set you have to do double work. Last thing you want is to be fudging engine position. Just tack the perches then adjust accordingly.
     
  25. THIS!!!! It's amazing how people wanna jump in without reading first. LMAO
     
    31Vicky with a hemi likes this.
  26. Hnstray
    Joined: Aug 23, 2009
    Posts: 11,471

    Hnstray
    ALLIANCE MEMBER
    from Quincy, IL

    That's a less common configuration, but I know it does occur on some really low setting rods. In that instance, I would agree the front of the pinion could/would/should angle downward IF the eng/trans centerline is also down to the rear and the angle formed by the drivehaft and pinion is the same as that formed by the driveshaft and eng/trans centerline.

    If, by chance, the engine/trans centerline were level, then so would be the pinion to maintain the same
    ujoint angle front to rear.

    Ray
     
  27. Hnstray
    Joined: Aug 23, 2009
    Posts: 11,471

    Hnstray
    ALLIANCE MEMBER
    from Quincy, IL

    Not necessarily on the same plane, but parallel when viewed from the side view. If the eng/trans and pinion are on the same plan, in side view, an offset pinion will accommodate the need for u-joint needle movement as the driveshaft will be running at an angle when viewed from above.

    Ray
     
  28. gimpyshotrods
    Joined: May 20, 2009
    Posts: 17,163

    gimpyshotrods
    ALLIANCE MEMBER

    No.
     
    trollst likes this.
  29. trollst
    Joined: Jan 27, 2012
    Posts: 1,726

    trollst
    ALLIANCE MEMBER

    I bolt the rear end in with the u bolts, continue on with the build, when most of the weight is in the car, I'll set pinion angle and weld the axle plates to the housing. As far as angles go, FOR ME, if the tranny is down three degrees, the rear yoke is up three degrees, parallel plane as viewed from the side. What Gimpy said, there's no way to set it otherwise.
     
  30. Joe H
    Joined: Feb 10, 2008
    Posts: 902

    Joe H
    Member

    No need to worry about engine and trans if the new one or rebuilt one is going back in the same mounts.
    If you are simply changing the rear axle, measure the old spring perch angles with the pinion level, or level the perches and measure the pinion, however you do it, set them the same and you are good to go.
     

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