Author Topic: CSX8000 Transverse Spring Questions  (Read 1483 times)

IslandCSX8000

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CSX8000 Transverse Spring Questions
« on: June 13, 2021, 03:06:12 PM »
Hi,
I have a CSX8000 with a rear transverse spring assembly that seems off center. The rear tires are shifted slightly towards the drivers side of the rear fenders. This is causing rubbing on the inner rear fender on the drivers side. The tires are 215/60-R15 Avons on OE wire wheels, and could reasonably be considered just a little large for the car. That said, if the tires had equal clearance on each side, looks like they should be fine.

My plan is to (after exposing the spring assembly) loosen the u-bolts and shift the spring stack over a bit. Seems like it needs 1/2 - 3/4". Never having done this, and not finding any reference to manipulating the spring assembly, thought I might ask for any guidance or advice. For instance, it would not surprise me if there was a locating pin that makes this 'adjustment' not possible.

Second question. I would like to raise the rear of the car at least an inch. Seems like every trip we take involves a full trunk, and the car rides fairly low even without that. Scraping mufflers and so forth. Is adding a leaf, or re-arching the springs a choice anyone here has made? I am in Northern California, so finding a shop experienced with re-arching might be a challenge?

Thank you for reading this. Anything that makes the car more driveable is a win in my book!

pbf777

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Re: CSX8000 Transverse Spring Questions
« Reply #1 on: June 14, 2021, 11:03:59 AM »
The rear tires are shifted slightly towards the drivers side of the rear fenders.

     The question is:  Is the spring and related suspension mounting positions actually "shifted" to one side, as measured from the frame, or is it the body work that is off-centered?

Quote
Is adding a leaf, or re-arching the springs a choice anyone here has made? I am in Northern California, so finding a shop experienced with re-arching might be a challenge?

     Adding "a" (may require more?) leaf, will raise the vehicle up, but additional leaves, arched to match the existing ones will increase the spring-rate and harshness of the ride; whereas "re-arching the existing spring stack will raise the vehicle with less effect on the ride harshness.     ;)

     Scott.

CSX2259

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Re: CSX8000 Transverse Spring Questions
« Reply #2 on: June 14, 2021, 11:23:06 AM »

The spring has a locating pin in the center that aligns with a hole in the spring tower, simply trying to move the spring by sliding it will not work in the manner you are thinking. Have you tried measuring the camber of each rear wheel to see if one side is more positive than the other? One side would be more negative and the other more positive when compared to each other. The spring acts as the upper control arm on the leaf spring chassis and the camber for each side should be very close to the same side to side. Is your car a glass body or aluminum body? What year was your car produced?
If you need any help with your car our shop is located in Southern California. We have re-arched springs for the Continuation Series Cobras and have a very good working knowledge of these cars.
You can email me directly at jkb5 at sbcglobal.net

IslandCSX8000

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Re: CSX8000 Transverse Spring Questions
« Reply #3 on: June 14, 2021, 02:28:52 PM »
Thank you so much for the replies!

I had a feeling there might be a locating pin ;-( This is a glass bodied car built in early 2017. It has been a blast to drive, but there are many things to be sorted. The tire rubbing has been bothersome, and I’m psyching myself up to pull the differential for a rebuild back at KMS. Gotten a fairly good howl going thanks to the breather defect…

CSX2259 I’ll reach out via email and see what we can figure out.

Thank you,

shelbydoug

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Re: CSX8000 Transverse Spring Questions
« Reply #4 on: June 14, 2021, 02:50:33 PM »
Since this is a fiberglass body, this probably doesn't apply.

If you look at the back of many CSX 2000 cars, the shape of the left fender does not match that of the right one. In fact, they look like they were hit in the rear on one side.

That makes using the fenders as templets for centering the tires and or the center of the rear, not possible.

I'd put the car up on an alighnment machine and see how square the entire chassis is. The original CSX cars were off "just" a little bit.  ;)
68 GT350 Lives Matter!

Don Johnston

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Re: CSX8000 Transverse Spring Questions
« Reply #5 on: June 14, 2021, 05:54:38 PM »
I aske Kei Iinuma for comments as he does not follow this forum.  SAAC members may know him as the owner/driver of #007 Series 8000 that has driven around visited all 50 States and been on the track at numerous SAAC conventions.  He and his wife load the Cobra with all their luggage and necessary tools or trips around the country.  His comments:

This situation may be a lot more complicated than moving the transverse spring slightly to the left.
    1.  If one should be able to move the spring to the left, this will cause the top of the tire to move outward, changing the camber, positive.  At the same time, the opposite will be true for the right rear tire.  If you can move the spring left, the right rear wheel will have more of a negative camber.
    2.  Theoretically, if the transverse spring were attached incorrectly, the lower control arms would also have been attached incorrectly and unless they are adjustable, as they are located on the frame, they are independent of the rear diff / spring and will also have to be corrected at the same time.
    3.  Without first ascertaining frame correctness ruling out an off-squared frame the transverse spring may NOT be the problem. 
    4.  I would not start with the spring.  First find out if the frame is square, then measure to see if the rear differential /  spring is centered and if it is the tire rubbing problem is not from a misaligned rear differential / spring perch.
    5.  The problem may simply be a body mod fix.  If it is a glass body, the form may be off.  If aluminum, then he can simply bang the body out a bit?
    Take the car to a reputable frame straightening outfit and confer with them regarding the squareness of the chassis before touching the mechanicals.

    Re-arching the spring is the traditional, accepted and proper way to go. 
    I use Gabriel Hi-jacker air shocks in the rear because we overload the Cobra with a trunk full of luggage, tools, and extra parts when we travel cross-country.  I put in 150 psi in the shocks to eliminate bottom-outs and release the air to 25 psi when I race the Cobra.
    I run Yokohama 225/45/15s all around.  They look kinda goofy because they don't fill the wheel well as well, but they are awesome on the track and from the front the little 289 looks very purposeful.

    Again, it is not recommended that the transverse spring and attendant mechanicals be experimented on to gain the half inch or so needed to eliminate the tire rub.  Look for and try other non-evasive tactics on this car.......that is the Cobra, a culmination of almost a century of experimentation on the transverse spring design may not like to be messed with.

    Don, if you want to, pass this info on.
Kei



pbf777

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Re: CSX8000 Transverse Spring Questions
« Reply #6 on: June 14, 2021, 09:26:10 PM »
    3.  Without first ascertaining frame correctness ruling out an off-squared frame the transverse spring may NOT be the problem. 
    4.  I would not start with the spring.  First find out if the frame is square, then measure to see if the rear differential /  spring is centered and if it is the tire rubbing problem is not from a misaligned rear differential / spring perch.
    5.  The problem may simply be a body mod fix. 
    Take the car to a reputable frame straightening outfit and confer with them regarding the squareness of the chassis before touching the mechanicals.


     I agree with this summation as being a reasonable approach, but realize that if the capable 'frame shop' is not available to you, or you wish to execute this on your own, it is quite possible thru the not so complicated process to "plumb-bob" the specific mounting points of the more complicated to measure three dimensional chassis converting such to a simple two dimensional observation that makes it much easier to identify any significant dimensional irregularities particularly those of the horizontal plane reference.     ;)

     Scott.
« Last Edit: June 17, 2021, 12:19:16 PM by pbf777 »

64cobra

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Re: CSX8000 Transverse Spring Questions
« Reply #7 on: June 14, 2021, 09:52:56 PM »
Contact Jesse at Shelby Parts.  He has had to “rework” several of these cars.
He did on mine and its 100% better now.

Jesse@shelbyparts.com

CSX2259

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Re: CSX8000 Transverse Spring Questions
« Reply #8 on: June 14, 2021, 10:22:06 PM »

IslandCSX8000,

I can’t begin to tell you how many of my CSX6000 Series (same as the 7000 & 8000) clients have had differential issues. It doesn’t help when the people installing the differential and routing the breather/catch can components haven’t a clue as to the fact that the differential is supposed to retain the fluid within it during operation and not be pumping gear oil all over the pavement. By the way you may want to check you axle flange, nuts, bolts and washers, the installer that put the other differential components in installed the 1/2 shafts as well and used generic hardware store crap, not something that you would want coming loose while driving! The installer typically used the crap on the left side in the photo, you need at least a proper shouldered bolt to go through the drive flanges.....

pbf777

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Re: CSX8000 Transverse Spring Questions
« Reply #9 on: June 15, 2021, 10:54:23 AM »
you need at least a proper shouldered bolt to go through the drive flanges.....


     This I agree with, and we often find ourselves shortening the threaded section on an otherwise to long of a bolt in order to have a greater shank portion length available for the instances of component alignment and shearing load application, as is being presented in the application described; but avoid using the flat washers, particularly the lower grade types, rather utilize flange head fasteners as this provides for a more stable installation engineering.     ;)

      Scott.

     

IslandCSX8000

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Re: CSX8000 Transverse Spring Questions
« Reply #10 on: June 15, 2021, 12:16:45 PM »
First let me say that I am blown away and very impressed by the thoughtful replies. I had a thought early on that maybe I should just go with a narrower tire to hopefully avoid the fender rubbing. You all have opened my eyes to the nuance involved, so maybe that was actually the right path from a fiscal point of view ;-). But we do love these cars, and that can have a big influence on how to proceed.

I don't have to tell any of you that these cars need a heaping amount of sorting. Sounds like the originals, right?

Surely more to follow, and I look forward to sharing what we find. Thank you.