Register now to get rid of these ads!

Lowering blocks and "herky-jerky"

Discussion in 'The Hokey Ass Message Board' started by Jay71, Sep 21, 2007.

  1. Jay71
    Joined: Sep 15, 2007
    Posts: 856

    Jay71
    Member

    Put some 3in. blocks on my buddys 53 Chevy. Now when he runs the car it gets real "herky-jerky" , but only when the car is at a dead stop to when it begins rolling. Hes really got to feather the clutch in and out to smooth it out. Its got the stock rear and enclosed driveline. Got some suggestions from other people about putting some wedges inbetween the leaves to adjust the angle of the rear or adjusting the linkage at the clutch fork. Wondering if anyone here has experienced this and what was your solution. Thanks
     
  2. lrs30
    Joined: Jan 30, 2007
    Posts: 2,210

    lrs30
    Member
    from Kentucky

    [​IMG][​IMG] I have 3 Inchers on mine and never had a problem..I'm curious as to what you find out??? Stupid question but after driving did you jack it up and re-tighten the U-Bolts, maybe everything settled into place under the weight of the car and loosened up a bit...Like I said I'm curious also....Good luck..
     
  3. newstranger
    Joined: Aug 2, 2005
    Posts: 587

    newstranger
    Member

    I have 3" blocks under my '52 and she's no more "herky-jerky" than she was before :D. I would definitely crawl under there and have a look-see.

    -ns
     
  4. Von Rigg Fink
    Joined: Jun 11, 2007
    Posts: 13,426

    Von Rigg Fink
    Member
    from Garage

    one thing to check is the U joint at the trans..its hidden inside that bell shaped "cover" see if it is binding..it shouldnt be..but it might be worn to the point that now that you have changed the driving angle it might need to be replaced..just a thought if all else is ruled out..
     

  5. Boynamedsue
    Joined: May 11, 2005
    Posts: 238

    Boynamedsue
    Member

    youll get axle wrap with the block more so than you would without. but usually its never noticeable or if it is its very slightly. is it a bounce or a jerk? it could be due to other worn suspension parts if its a bouce and it does it multiple times before it quits you might want to check the shocks and srping. it could also be a bad u joint causinf driveshaft movement
     
  6. Jay71
    Joined: Sep 15, 2007
    Posts: 856

    Jay71
    Member

    The "jerk" is similar to the one you get when you are first learning to drive a stick. New shocks all around. Also, theres 2 coils out of the front, dont know if that plays into it to.
     
  7. Gr8ballsofir
    Joined: Apr 21, 2001
    Posts: 768

    Gr8ballsofir
    Member

    Try tilting the motor with a spacer, under the trans tail shaft, to adjust for the new drive shaft angle.
     
  8. lrs30
    Joined: Jan 30, 2007
    Posts: 2,210

    lrs30
    Member
    from Kentucky

    I also chopped ofF 2 coils.. Sounds like something come loose....Keep me posted very interested..
     
  9. PeteFromTexas
    Joined: Apr 4, 2007
    Posts: 3,837

    PeteFromTexas
    Member

    I've got 3 inch blocks under mine and it is smooth and nice on take off. Also 2 coils cut out of the front with worn out shocks and springs all the way around. I'd bet something is loose under there.
     
  10. SLVRBLLT40
    Joined: Jun 18, 2007
    Posts: 27

    SLVRBLLT40
    Member
    from Orange, Ca

    Sounds like something is loose or misaligned. There's 3 in. lowering blocks on my '72 Newport, and it only does the teeth-shatter-jitter if ya punch it off the line. Axle has too much leverage on the rear leaf springs.
     
  11. lrs30
    Joined: Jan 30, 2007
    Posts: 2,210

    lrs30
    Member
    from Kentucky

    Damn dude you stole my car....same here, but I put Air Shock's on the back to give the bump stop a break......
     
  12. PeteFromTexas
    Joined: Apr 4, 2007
    Posts: 3,837

    PeteFromTexas
    Member

    I know dude. Mine is all going to change soon with dropped uprights, lowering springs and posies rear leaf that lower it 4 inches. Plus the gas shocks all around for the sake of the bump stops...
     
  13. Bugman
    Joined: Nov 17, 2001
    Posts: 3,483

    Bugman
    Member

    I would suggest spring wrap, but I don't know if that's possible with a torque tube?
     
  14. Jay71
    Joined: Sep 15, 2007
    Posts: 856

    Jay71
    Member

    Not sure what "spring wrap" is. Can you please explain. Thanks for the help.
     
  15. MotorBike Mike
    Joined: Mar 21, 2006
    Posts: 325

    MotorBike Mike
    Member

    I have a 54 chevy with the same blocks and the same problem. Only mine didn't get real noticable untill I put my new motor mounts in...

    You nailed it on the head when you said it jerks like learning to drive a stick... I think it has to do with the angle of the motor/trans/driveline/rearend. Because basicaly it's all one long unit thats bolted together, unlike a driveline with "real" u-joints the angle and any travel in it is all related. The only pivot in the whole setup is right at the "bell cover".

    It did what I call the "Harlem shuffle" when I first put in the blocks, but it was very faint. As soon as I replaced the old original mounts for some new ones, they increased the height of the motor by about an inch. Then it starded doing the harlem shake! :D And because that rear end has locating pins you cant really adjust the angle of it either, thats why I'm in search of a 60's 3 speed tranny that I'm going to use with a'57 chevy rear end that I have to convert it to an open driveline. Then I'll never have to worry about it again.

    As fas as anyone else not having this specific problem, I think It's something that only happens to manual cars with a enclosed driveline, as opposed to powerglides or any one who has already converted to and open driveline. The angle might not effect the car as dramatcialy with the powerglide setup because there is no clutch action is what I'm thinking.

    But we'll see when I convert it over ;)

    Mike
     
  16. 40chev
    Joined: May 28, 2002
    Posts: 209

    40chev
    Member

    are these blocks straight (flat) or are they angled to correct the angle of the driveshaft?? If they are flat blocks dollars to doughnuts the driveshaft is binding....
     
  17. Jay71
    Joined: Sep 15, 2007
    Posts: 856

    Jay71
    Member

    The blocks are flat. Ive never seen any blocks with angles already milled in them. Does anyone make them? I believe your right about the drive shaft binding. A driveline specialist told me to put some wedges inbetween the leafs to adjust the angle. We may be on to something here.
     
  18. Sam F.
    Joined: Mar 28, 2002
    Posts: 4,225

    Sam F.
    BANNED

    is your rear end stock???? if it's not,,check your pinion angle,,

    i picked up a car last week ,,drove great,,lowered it and the pinion angle was way off ,,had to cut the perches loose and re set the pinion angle...


    (sorry,,just re-read you question and saw you still have stock drive line,,,)
     
  19. leaded
    Joined: Nov 17, 2005
    Posts: 326

    leaded
    Member
    from Norway

    Did get some similar movement on lowerin my -50 Fleetline. Was handbrake cables making stretch when heiht posision haned. I´ve also ot airadjust at rear, and when setted to rideheight everythin was ok. But lowered ....shaked to move. The orinal handbrake cable outer hose is of very stiff baidin, and posisioned between brakeshield and to holders at the frame, they didnt move as should, but stretched the cable nstead ivin some brakefore. Replaed the framemount to a clip on the axle,and everythin was ok.:cool:
     
  20. flathead fred
    Joined: Jul 18, 2006
    Posts: 298

    flathead fred
    Member

    your pinion angle is probably off. this is basically the relatioin of the driveshaft to the rear axle, all this needs to be fairly straight at rest. Speedway does sell block shims for adjusting pinion angle, just be careful about stacking too much between axle and springs
     
  21. Gummi Bear
    Joined: Sep 6, 2006
    Posts: 129

    Gummi Bear
    Member

    It's likely a combination of several things:

    • Spring wrap - the pinion gear tries to 'climb' the ring gear, and with the extra leverage you've given the axle to twist the leafs into a W shape with the blocks, off she goes. Spring wrap happens in two different planes, so a single point connection traction bar won't solve all of your woes. The top of the axle is trying to move backwards, while the bottom is trying to move forwards. http://www.4x4wire.com/jeep/tech/susp/ladbar/ Here's a tech article on the style of bar, and how it mounts. Yes, it's for a Jeep, offroaders have more axle wrap issues than most, with lots of torque, traction and huge tires it becomes blaringly obvious that there's a problem back there.
    • Blocks, I'm not a fan, but they've been around for longer than me, and don't appear to be going anywhere. I'm hoping that these are a manufactured type, and not just a piece of 2x4 tubing that you chopped off.
    • U-bolts - when you increase the stress on your running gear with adding a higher fulcrum point, you need to beef these up. The corny little 3/8" unit's won't cut it. I'd say start looking at some 5/8" bolts, and if you need a new plate, so be it. Any good spring or driveline shop can bend them up for you in the right radius and length.
    • Pinion angle - it needs to be corrected. Here's a good article on what to look for, and how to address it: http://classicbroncos.com/pinion_angle.shtml You can buy shims (get the steel ones, and new centering pins for your leafpack at the same time) look at the degree shims: http://www.rubiconexpress.com/Builders-Parts.aspx?Vid=9267323639344 or you can look at the blocks with the appropriate correction degree already milled into it:http://www.rubiconexpress.com/Products.aspx?Cn=350&XnPath=320,322&Vid=9267323639344
    • Worn out mounts - address them. Spring bushings, shackle bushings, tranny x-member, motor mounts. All of these things need to be taken care of. You can put in new polyurethane ones, which depending on durometer can stiffen up things, or you can go back with OEM rubber mounts for everything. Figure on most of a weekend to replace all of these.
    • U-Joints - this is a biggie, and often overlooked and ignored. Another off road site tech article, but it's informative. I run the Spicer XPL (Life) series joints in everything I own. http://pirate4x4.com/tech/billavista/PR-shaft/index.html
    I hope this all helps.
     
  22. Jay71
    Joined: Sep 15, 2007
    Posts: 856

    Jay71
    Member

    Thanks for all the usefull information. With all your suggestions Im sure well be able to smooth things out. Also since it was my first thread thanks for not putting me through any hazing rituals.:D
     
  23. 40chev
    Joined: May 28, 2002
    Posts: 209

    40chev
    Member


    Yes and I have a set LOL....I bought these about 15 plus years ago, they are steel and are angled to correct the driveshaft geometry......Below is a couple of pics of the blocks I have.....I purchased them from a 4X4 shop for trucks but they work for cars just as well...
     

    Attached Files:

  24. 19Fordy
    Joined: May 17, 2003
    Posts: 7,627

    19Fordy
    Member

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.