Cyclic intensity front end shimmy

  • Stevedavis
  • Stevedavis's Avatar Topic Author
  • Offline
  • New User
  • New User
More
12 May 2017 03:10 #32919 by Stevedavis
Stevedavis created the topic: Cyclic intensity front end shimmy
I recently bought an 812 Custom Beverly and am looking for ideas why the car has what I can best describe as a cyclic intensity shimmy. Going down the road at 45 mph (3rd or 4th gear doesn't matter) and after about 1/4 mile the front end starts a slight shimmy, but over the next 2/10 mile the shimmy gradually increases to its maximum intensity (fairly severe). Then over another 2/10 mile it gradually and completely goes away. Then after another 1/4 mile the cycle starts again. The first time I encountered the issue was my first time driving the car while not in town, and it happened as I was approaching 55 mph. At that speed the maximum intensity of the shimmy was so bad that the entire car was shaking almost violently. Since the shimmy doesn't occur all of the time I believe I can discount wheel imbalance. Since the problem exists in both 3rd and 4th gears I believe I can discount transmission gearing. Can anyone clue me in as to what is causing this issue and what I might be able to do to remedy it?

Please Log in or Create an account to join the conversation.

More
12 May 2017 04:26 #32920 by 1748 S
1748 S replied the topic: Cyclic intensity front end shimmy
tHERE ARE MANY REASONS FOR WHAT YOU DESCRIBE. lOOSE STEERING LINKAGES ON BOTH SIDES CAN CAUSE ALL KINDS OF SHIMMY.sO CAN THE CENTER BOLT THAT HOLDS THE STEERING "y" IN FRONT OF THE CAR. a SET OF BAD WHEEL BEARINGS CAN ALSO BE THE CAUSE. sADLY THOSE ARE NO LONGER MADE SO i CAN'T SUGGEST A REPLACEMENT FOR THEM. oTHERS MAY HAVE THE REPLACEMENT BEARING SIZE. i HAVE EVEN HEARD LOOSE TRANS MOUNTS OR ENGINE MOUNTS CAN CAUSE SHIMMY. sO YOU HAVE PLENTY OF PLACES TO LOOK FOR LOOSE PARTS. Sorry I was not yelling.I do not watch the screen when typing but watch the keyboard for the next letter. Then fat fingers hit just the edge of the caps and letter A key.

Please Log in or Create an account to join the conversation.

  • Terry Cockerell
  • Terry Cockerell's Avatar
  • Offline
  • Forum Contributor
  • Forum Contributor
More
12 May 2017 06:46 #32922 by Terry Cockerell
Terry Cockerell replied the topic: Cyclic intensity front end shimmy
After checking everything for correct adjustment and removing any wear or slop from things like the centre steering arm pivot the next thing to do is balance the brake drums and wheels separately. I wrote an article on balancing my brake drums in the Cord Forum. Separately is best as you will move wheels around from time to time. A front end alignment using the Factory Specs must be done. Then after all the above has been done you need to look at the rear springs as they usually sag which lowers the rear end too much and this changes the front end geometry.
The rear springs are often overlooked.

T cockerell
The following user(s) said Thank You: 1748 S

Please Log in or Create an account to join the conversation.

  • mikespeed35
  • mikespeed35's Avatar
  • Offline
  • ACD Club Life Member
  • ACD Club Life Member
More
12 May 2017 15:47 #32929 by mikespeed35
mikespeed35 replied the topic: Cyclic intensity front end shimmy
I had a shimmy on my Marmon 16 above 60MPH and it turned out to be bad front shocks. Just a thought.
CORDiallyMike

Mike Huffman

Please Log in or Create an account to join the conversation.

More
13 May 2017 01:28 - 13 May 2017 21:01 #32937 by Tom_Parkinson
Tom_Parkinson replied the topic: Cyclic intensity front end shimmy
The double ball bearing from the steering W bellcrank shows up on EBay occasionally. Goes for about $80 when it's there. It was also used in GM applications.

It was also available from OLCAR Bearing Co, Southern Pines, NC, a few years ago; might still be. It is new Departure 900916.

--Tom

With brakes, two cylinders are better than one.

Editor-in-Chief, The Hardtop News Magazine, the Journal of the Michiana Dunes Region, Lambda Car Club International

See pix of 1509A here: http://mbcurl.me/YCSE
Last Edit: 13 May 2017 21:01 by Tom_Parkinson. Reason: Added info.

Please Log in or Create an account to join the conversation.

More
13 May 2017 17:09 #32943 by johnmereness
johnmereness replied the topic: Cyclic intensity front end shimmy
You may just want to jack the car up and see how true the tires run via hand spinning - I have seen some really oval and square tires out there (and often right out of the wrapper).

We are very fortunate in Cincinnati to have a race guy who does not mind working on 30's cars and has a mind for getting geometry right. Surprisingly, he had a program for a 1935 Auburn via Hunter and we just drove it onto the rack, hooked up all the gauges, and adjusted the car - fabulous on the road, but only as good as the quality of its tires (which leave something to be desired).

JMM

Please Log in or Create an account to join the conversation.

Time to create page: 0.240 seconds
Powered by Kunena Forum