Register now to get rid of these ads!

frame help...dbl z frame with Model A rear crossmember

Discussion in 'The Hokey Ass Message Board' started by oldskoolflyer13, Jun 21, 2011.

  1. oldskoolflyer13
    Joined: Mar 29, 2009
    Posts: 274

    oldskoolflyer13
    Member

    So this past winter I purchased a double z frame from Riley Automotive. At the time I wasnt factoring in a quick change on the rear end. The frame comes standard to accept a '40 rear spring....which we all know doesnt work with a QC. So now, Im trying to figure out my options.

    Here is what I know about the frame.....113.5 inch frame, 106 inch wheelbase (center spring hole to center spring hole), center rear crossmember from centerline of axle is 7.5"..........

    To place a Model A rear crossmember in the rails....would I just have to locate it 7.5" in wards from the center hole of the '40 style rear CM to center hole of Model A rear CM? Plus change the rear end spring perches to model A on my '41 Ford rear...or the '39 which ever I use.

    Side note....this isnt a thread to complain about Riley Automotive or Eric, we all havent had bad experiences...so lets keep this on topic. Thanks!
     
  2. sounds like you are on the right path
    if you want the 106 wb then just put the a crossmember centered at the 106 and you should be good to go
    a spring is 2 1/4 thick
    t spring has a higher arch and looks a little cooler
    it is 2 in thick
    just some food for thought
    tk
     
  3. oj
    Joined: Jul 27, 2008
    Posts: 6,257

    oj
    Member

    7.5 forward, 3.5 higher to keep same ride ht. Or just send that QC up to me and keep what you got. Can't use model 'a' tubes with qc, need V8 bells and a model 'a' mounting kit. I got a good clean pair of V8 bells without any mounts on them if you need a set.
    Later oj
     
  4. oldskoolflyer13
    Joined: Mar 29, 2009
    Posts: 274

    oldskoolflyer13
    Member

    3.5 higher?....of course this couldnt be as simple as weld it in. Ive got V8 bells ('39 and '41)....just need the "A" mounts for which ever one.

    Without reconstructing the back end of the frame is it is possible to get that 3.5 from reversed eyelets and some springs removed?

    Ive seen pictures of the same frame as I have with a Model A crossmember and it doesnt appear to have anymore kick up than the 8" on mine.....
     

  5. oldskoolflyer13
    Joined: Mar 29, 2009
    Posts: 274

    oldskoolflyer13
    Member

    Will the A rear crossmember raise it 3.5"?
     
  6. oldskoolflyer13
    Joined: Mar 29, 2009
    Posts: 274

    oldskoolflyer13
    Member

    A posie rear spring will get me down 2.5"....how much more can you safely adjust out of the spring pack?
     
  7. Zombie Hot Rod
    Joined: Oct 22, 2006
    Posts: 2,453

    Zombie Hot Rod
    Member
    from New York

    I would start by putting the front end on the frame. . . then put spring on the rear, bolt it to the cross member, and roll it under the car to see where you're at.

    Putting Model A spring hangers on the rear axle is going put the back of the frame way up. I know that the frame is "Z-ed", but it may not be enough to give you a good ride height, or if it's "Z-ed" too much to use the '39/'40 spring hangers.

    You can measure and visualize, but if you have the parts, mocking up and measuring is better than trying to imagine what it's going to look like.

    . . . also seems king of silly to cut the stock spring hangers off of a later axle, weld Model A hangers on top, then use a two and a half inch lower, after market spring to bring the back of the frame down again.
     
  8. oldskoolflyer13
    Joined: Mar 29, 2009
    Posts: 274

    oldskoolflyer13
    Member

    In order to run a QC...you need a Model A crossmember....and with that you need spring-on-top hangers for 37-40 rear ends. Not unless there is a different method I dont know about to mount a non Model A rear end to a Model A rear spring.

    Cutting off the hangers and replacing with new spring-on-top hangers isnt silly....been done for a long time. The aftermarket spring to get the frame back down would be to compensate for the 3.5 in rise (if there is any) by mounting the A rear cm between the rails as it sits.
     
  9. chopt top kid
    Joined: Oct 13, 2009
    Posts: 959

    chopt top kid
    Member


    No...No...No... Locate the model A crossmember where the crossmember for the '40 spring goes. Use a stock Model A spring. Use the stock spring perches on the '40 style rear banjo...
    The Model A spring is shaped like it is to clear the rear diff in a stock Model A spring over setup. Hot rodders have been using the Model A crossmember and spring forever to clear the quickchange unit in a spring behind the axle setup...

    Here are a good set of pic's showing a Model A crossmember and spring used in a spring behind axle setup with a quickchange. This chassis uses deuce rails but the same setup could be used with your Riley Automotive frame... http://www.jalopyjournal.com/forum/showthread.php?t=454896
     
    Last edited: Jun 22, 2011
  10. oldskoolflyer13
    Joined: Mar 29, 2009
    Posts: 274

    oldskoolflyer13
    Member

    Im trackin with ya now......will that still bring the axle 7.5 inches forward to the 106" wheel base? Wouldnt the stock model a spring bring the ride height up to much?
     
  11. oldskoolflyer13
    Joined: Mar 29, 2009
    Posts: 274

    oldskoolflyer13
    Member

    maybe its time to just throw in a currie.....
     
  12. Zombie Hot Rod
    Joined: Oct 22, 2006
    Posts: 2,453

    Zombie Hot Rod
    Member
    from New York

    [​IMG]

    Above: Quick Change center section using '40 Ford side tubes (with the original spring hangers), a Model A cross member and Model A spring.

    You do need to use either a Model A, or Model T spring and cross member to clear the Quick Change, but you don't have to mount the spring up top.

    When I said it's silly. . . I mean it's silly to cut the hangers off of the '40 axle, weld new hangers on top, then get a new lower spring to bring the rear back to the height it would have been if you didn't cut the original hangers off in the first place.

    Mount the cross member to the spring, mount the spring to the axle, and mock it up.

    What sort of axle as your frame designed to be used with?

    . . . but who knows, with the height of the "Z" on your frame, the spring on top might work out better cause you don't have to modify the frame. . . it may also work against you.

    You really need to mock things up BEFORE you start cutting to get a better idea of where you're at, and which direction you should go in.
     
    Last edited: Jun 22, 2011
  13. oldskoolflyer13
    Joined: Mar 29, 2009
    Posts: 274

    oldskoolflyer13
    Member

    I dont think there is specific on the axle , people run various rear ends with these frames. He builds them with the rear Model A crossmember also (looking at pictures both styles look almost identical minus rear crossmember)...was kind of a oversight on my part. Im picking up a rear crossmember this weekend and a rear spring..to mock up.

    If I can put the model a crossmember in place of the current one and mount the axle spring behind and come out with 106" all is good......my main worry is the ride height becoming altered too much where i would be struggling to get it back down to where it would be now.
     
  14. oldskoolflyer13
    Joined: Mar 29, 2009
    Posts: 274

    oldskoolflyer13
    Member

    by no means will I be going and cutting things up first. Step 1) Run this across the HAMB and see what gets thrown out there....Step 2) mock it all up in various ways and choose.....Step 3) mason jar + bourbon + coke + ice......maybe that was step 2
     
  15. chopt top kid
    Joined: Oct 13, 2009
    Posts: 959

    chopt top kid
    Member

    Yes, you can measure the distance from the centerline of the axle to the centerline of the stock spring perch to be sure.

    No, the "extra arch" in the Model A rear spring is compensated for by the "extra arch" in the Model A rear crossmember. The final ride height is determined by fine tuning the spring pack...
     
  16. oldskoolflyer13
    Joined: Mar 29, 2009
    Posts: 274

    oldskoolflyer13
    Member

    basically the only way I would gain height (or at least a noticeable amount) would be by using the perches on top. Its all coming together up in the head now....
     

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.