Register now to get rid of these ads!

Rear spring hangers question

Discussion in 'The Hokey Ass Message Board' started by baspinall, Oct 24, 2012.

  1. baspinall
    Joined: Dec 8, 2009
    Posts: 447

    baspinall
    Member
    from SE PA

    I have these spring hangers laying around that I had planned on using for my build. Problem is I can't get them spread far enough apart on my 8 inch rear to cover the 49.5 in eye to eye I need. So here is my questions. I have a stock Model A coupe spring. Am I correct that my hangers need to be mounted 49.5 inches apart eye to eye? If that measurement is correct I need to get different hangers.
    My second question is before I tack the hangers on should I have the rear positioned 3 degrees pos. up? I have heard guys say all the way to 6 degrees.
     
  2. baspinall
    Joined: Dec 8, 2009
    Posts: 447

    baspinall
    Member
    from SE PA

    The hangers in question.
     

    Attached Files:

  3. MikeRose
    Joined: Oct 7, 2004
    Posts: 1,583

    MikeRose
    Member
    from Yuma, AZ

    You could get a narrower spring, if your rear end is too narrow for the stock A spring. Posies 28-31 RC uses 46 - 46 1/2" Perch Centers. I have one for sale. I need the standard eye posies spring.
     
  4. aaggie
    Joined: Nov 21, 2009
    Posts: 2,530

    aaggie
    Member

    The hangers (shackles?) should be at a 45# angle with the weight compressing the suspension, never heard of it having to be any certain dimension. As far as pinion angle it should be set at 3# down angle, again with the weight on the suspension and the frame at ride height.
     

  5. baspinall
    Joined: Dec 8, 2009
    Posts: 447

    baspinall
    Member
    from SE PA

    The rear isn't to narrow for the spring it's the design of this particular spring hanger/perch I am questioning. If I use the type of hangers that are laying on the floor (those are trashed & bent) in the picture I can get them welded up far enough apart. Just thought guys have used this type of hanger on 8 inch rears in the past.
     
  6. I think your 49.5" is correct -1.5 each for shackles=3" leaves 46.5 Spread the main leaf on to shackles then add addl leaves.Do you have a spreader?spring has lots of force!
     
  7. The first thing you need to do is take the spring apart. Now try to spread it to reach your pearches. You are using a spring spreader aren't you?? Upon reassembly after connecting to the perches only use every other leaf.
     
  8. baspinall
    Joined: Dec 8, 2009
    Posts: 447

    baspinall
    Member
    from SE PA

    Thought the 49.5 was right. I am just going to get my hands on a good set of perches like my bent up ones laying on the ground in the photo. Those I can weld outward further than the others.
    Yeah I have a spring spreader.
     
  9. Koz
    Joined: May 5, 2008
    Posts: 2,699

    Koz
    Member

    I know exactly what your talking about. I get this frequently in here. I use, or you could fabricate the ones SoCal sells for "A"s which can be run almost to the bearing cups. They look like this....

    [​IMG]

    The rear in the pic is a nine inch we narrowed and centered to almost the same dimension as your's. That is a stock width spring and the correct dimension hanger to hanger for a Model "A" spring is 49 1/2" although you can sneak them in an inch on a light car and get away with it. The Speedway mounts are OK on wide rears but pretty useless on most others.

    Here's another pic of the same hangers used on a banjo..

    [​IMG]

    Hope this helps.
     
  10. baspinall
    Joined: Dec 8, 2009
    Posts: 447

    baspinall
    Member
    from SE PA

    KOZ - Exactly what I was thinking. Thanks. Deer lake huh. I just worked at an old Sunoco in Hamburg the other day. Small world.
     
  11. NortonG
    Joined: Dec 26, 2003
    Posts: 2,117

    NortonG
    Member Emeritus

    This is pretty helpful info here.
    I was looking for the spring hanger mounting width for my build.
    Thanks guys!
     
  12. baspinall
    Joined: Dec 8, 2009
    Posts: 447

    baspinall
    Member
    from SE PA

    "As far as pinion angle it should be set at 3# down angle, again with the weight on the suspension and the frame at ride height."

    Isn't this supposed to be up? The tailshaft of the transmission is angled downward.
     
  13. Koz
    Joined: May 5, 2008
    Posts: 2,699

    Koz
    Member

    The angle of the rear is related to the angle of the engine trans. In other words if your trans sets at 3 deg. down then your rear should be parallel if that makes sense. Drag racers set the rear with a 3 deg. angle to compensate for spring wrap up on leaf set ups until the slapper bars lock. On the street it's not required or desired. The trans and the rear don't need to be in line, just at the same angle. This way when your driveshaft turns, the universals technically run faster at 90 deg. than they do at 180 deg. This is why you "phase" universals in a driveshaft. Just set the two at the same angle and your fine.

    This explaination is clear as mud. I think you get the drift though. If this is confusing call me in the shop. The # is my HAMB-O-Dex.
     
  14. baspinall
    Joined: Dec 8, 2009
    Posts: 447

    baspinall
    Member
    from SE PA

    All makes sense just thought I missed something. One thing that still confuses me is the order in which you set things up. I have my engine ready to install. I have not located the placement of the tie rod mounts for my split bones yet. Then I have the rear to set up. Should I mount the engine first set the ride height in the rear with jack stands then mark the bones placement and go to the rear. Or the other way around? Kinda hard to explain this typing it out. maybe I'll give you a shout. Oh and all this is on a wavy gravy garage floor.
     
  15. I always thought the 2 angles were supposed to cancel each other out. If the trans is 2 degrees down then the rear should be 2 degrees up equaling Zero degrees?
     
  16. NortonG
    Joined: Dec 26, 2003
    Posts: 2,117

    NortonG
    Member Emeritus

    That doesn't equal zero. They're parallel...

    It takes the vibration out with them rotating at the same angle.
     
  17. tlmartin84
    Joined: Jul 28, 2011
    Posts: 1,030

    tlmartin84
    Member
    from WV

    I hate the 3 degree thing, what you are looking for is 173 degrees between your drive shaft and yoke, and 173 degrees between driveshaft and transmission.

    From what I have gathered engines are typically mounted at 3 degrees off of level....hence the 3 degrees at the yoke. It wouldn't matter if you mounted striaght up (theoretically) as long as it and the engine are parallel with 173 degrees between them.

    Check this site.

    http://www.quickperformance.com/Technical%20Info/Pinion_angle.htm
     
  18. Don's Hot Rods
    Joined: Oct 7, 2005
    Posts: 8,319

    Don's Hot Rods
    Member
    from florida

    I have exactly the same perches you show laying on the floor on the back of my 27. They have been on there for over 20 years and work fine. I tried using the ones you have sitting on top of the housing in that one picture, but they moved the perch hole too far inboard. As it is, the flat ones are mounted just about an inch off of the backing plate, but they did work there.

    If needed, a spring shop can make you up a shorter main leaf. I had one made for the T spring I used years ago and the cost was only $ 28. But a couple of years ago I went and had the same place make me a new one and it was $128 ! Inflation !!:eek: But sometimes you gotta spend a few bucks to solve a problem and move on.

    As for the angle thing.........I am not good at math so I keep it simple. I point the motor down 3-4 degrees and point the rear end yoke up a corresponding amount, and call it good. After a bazillion miles on my 27 I still have the original U joints in the car from over 20 years ago, with no vibrations whatsoever, so I guess it works.

    Don
     
  19. Koz
    Joined: May 5, 2008
    Posts: 2,699

    Koz
    Member

    Commenting on tlmartin84's post above. The site you reference is for a drag car. This does not apply to the street where there is usually little or no wrap on the springs. Most of the guys arrive at the same conclusion, to match the pinion and trans angle. What Don says above is exactly what should be done. It doesn't matter how you arrive at that position as long as they match. Seven deg. on a street car is going to drive you nuts and eat universal joints.
     
  20. That doesn't equal zero. They're parallel...
    ???
    New math???
     
  21. Don's Hot Rods
    Joined: Oct 7, 2005
    Posts: 8,319

    Don's Hot Rods
    Member
    from florida

    I should interject that when I say 3 down and 3 up it does not mean the driveshaft is shooting directly in a straight line from the tailshaft to the yoke. My tailshaft sits lower than the rear yoke so the driveshaft goes uphill slightly, which forces the U joints to "work" as they turn. This keeps the bearings evenly stressed and prolongs their life.

    Don
     
  22. tlmartin84
    Joined: Jul 28, 2011
    Posts: 1,030

    tlmartin84
    Member
    from WV


    It has do with the rear axle movement, not just "wrap" it can be a bump in the raod. As the rear axle moves up the drive shaft angle flattens out. Picture it in your mind....your crank is parallel with the yoke if you compress them and make them coplanar. The straighter they are the better but since the rear moves they can't be straight.

    I am saying the exact same thing as don and everyone else here. It is the same in the site I list above. the yoke in the drawing is set at 3 degrees from vertical.

    It also depends on the height of the crankshaft above the yoke shaft. If you set them each at 3 degrees, the further the distance between them the more the angle grows. It involves vertical distance, horizontal distance and the angles. To do it correctly there are more factors than just checking angles at the engine and yoke.
     
  23. baspinall
    Joined: Dec 8, 2009
    Posts: 447

    baspinall
    Member
    from SE PA

    All informative info for me. Figuring on getting my engine in so I can get the weight on the frame and set that angle first then move to setting up the rear.
     
  24. tlmartin84
    Joined: Jul 28, 2011
    Posts: 1,030

    tlmartin84
    Member
    from WV

    I miss spoke earlier, the yoke in that drawing is set at 4 degrees from vertical...........

    In most of our builds setting and angle finder on the face of the yoke and back of the motor should yield the same/opposite angle of 3 degrees. It is not a big issue.

    Where it really shows up is on offroad jacked up trucks. the higher the body and motor goes from the rear axle the larger degree of shim is required to rotate the nose of the yoke up. While the shims help the pinion angle, they do nothing for the u joints at the transfer/transmission.......... they typically wear much faster
     
  25. Koz
    Joined: May 5, 2008
    Posts: 2,699

    Koz
    Member

    Your right we are basicly talking about the same thing here. I think we need to note there are a lot of variables here and what most result in some compromise. From a drive angle position, the four ink is obviously the best and a set of ladders the worst from a purely engineering standpoint. The Ford banjo set up works beautifly which is just a set of fixed ladders, and in fact is one of the worst geometrically with it's single universal. The site you mentioned above is great info for a drag car, and being a Nova site, most likely refers to the parallel leaf setup we discussed earlier. Most rear suspension setups these days are so adjustable we usually get them as close as I can and when the car is in final setup I throw 300lb of sand bags on the seat to simulate a driver and passenger, ( or in some cases a driver), and set the rear pinion accordingly. ( Just for the record, this is the factory method they use to set up full size Jaguars prior to the new active suspensions). Obviously on suspensions that do not allow this adjustment the angle must be engineered in. Like most hot rodding stuff this isn't rocket science and is somewhat forgiving. In short, what is good for a drag car or monster truck may not be good for that streeter on the way to the shore.

    I love when we have these discussions because everybody on here has picked up info along the way and we're all constantly learning and improving our craft. When I worked at Dana I spent a good bit of time picking enginnerings' brains on all matters of chassis setup and I was amazed at the wide spectrum of answers I would get on the same question. Good stuff here!
     

Share This Page

Register now to get rid of these ads!

Archive

Copyright © 1995-2021 The Jalopy Journal: Steal our stuff, we'll kick your teeth in. Terms of Service. Privacy Policy.

Atomic Industry
Forum software by XenForo™ ©2010-2014 XenForo Ltd.