Rear suspension problem. (Lone Star)and other's.
 

I have a rear suspension problem. I have a Lone Star but this situation can be for other makes.

This was to be a short post but sorry, it's not. Please bare with me. I need some input from you guy's.

I was never happy with the height of Lone Star Cobras rear end, too high. I have a straight axle and realize it won't sit like a IRS but, I prefer the look on all cars, to be level and the tire filling up the wheel well.(it's popular now to have 17" wheels and low profile tires, sorry but, I don't care for this look. Even as a teen, my Camaro sat level where as my brother had a 73' Charger, and made longer shackles, like 8" long ! Looked silly !!!

Anyway, a buddy & I were on a club's "turkey run" (very fun)it was a old highway with rough railroad tracks. You know how sometimes if you go fast, you almost float across them, well I tried that and this time, it was a mistake I blew the rear seals on my Aldan coil overs.


Even before this happened, I thought my Cobra had a pretty rough ride. I told Rich Anderson of "Shell Valley" about this and he said to throw away the Aldan's and get QA-1's, he said it made a big difference in ride quality. So, I decided to replace all the rear heim joints (one was very sloppy)and buy
QA-1's.

Since we race 360 sprints and know several guy's that race IMCA modifies, I borrowed a set of four scales to see what each corner weighed, front, rear and combined total. I weighed the car after completion in 2002 at our small town's coop scale. It was 2,400 lbs. with my fat @ss in the car, full of fuel
(20 gallons)

Here's the numbers with out me, in the car. So, let me know what you think.

LF- 694
RF- 612 (Difference of 82 lbs.and don't know why)?

LR- 650
RR- 708 (Difference of 58 lbs.)(Battery in RR)

Total front = 1306 lbs.
Total rear = 1358 lbs. (difference of 52 lbs.)

Total weight = 2663 lbs. (with the wide whees and big tires, I'm sure add a lot in static weight. It would be interesting to weight them)

Percentage- Front = 49%
Rear = 50.9%

I was surprised of the total weight, although, I know Lone Star has one of the strongest frames on the market. And I have a big block. But, I heard of similar cars weighing 200-400 lbs. less. (I know of a all carbon fiber bodied car with a aluminum monocoque chassis weighed 1850 lbs.) !

The percentage is remarkable. I believe because the car is stretched 4" in the cockpit and the engine sets back pretty far.

What do you think of the results ?

Problem- The frame is straight and level. But, the right rear wheel house was 1.25 higher from the ground that the left rear. Take a look at the difference of the height adjustment collar on the coil overs. The left rear is all the way down while the right rear is almost 1/3-1/2 of the way up ?

The springs are both 10" and tensile strength were both 230 lbs. I was told by "Speedway Motors" to use 220 lb springs. My mechanic friend went to a suspension seminar and the instructor said that most people use way to heavy of springs on the car. One kit car business I called said they use heavier springs than needed, so customers can't complain that the tire hit & damaged the wheel well and that you have some liking a stiff racing type ride and others liking the soft cushy ride. Well, as I see it, that should be in adjusting the dampening of the shock and not relining completely on the springs.

I measured the height of the mounting brackets on each side and they're very close. I have not seen any stand out differences yet.

The only thing I can think of is the body mold was off from when mine was made but, I have heard from another Cobra owner that he knew of a car that the wheel well had to be cut and lowered 1.5". I'll have to schedule some time at my friends auto body frame machine and start measuring the frame and body points.

For a test, I removed the shocks, and took some steel tubing, welded a nut on each end (call them struts) and threaded on heim joints, making sure they were both the same in length. This not only was for testing the suspension but also for getting the ride height I want.

Then measured the height of wheel well again. It lowered the height apx.
1/4". I'll be curious with the new QA-1 shocks make a difference when I'm all done. With the mocked up struts measurements, I doubt there will be a difference.

I did however, move the top 4-bars to the top brackets (there are two holes on the brackets, higher & lower mounting points)and the lower bars to the lower holes because, when the car was on the ground, the 4-bars were at a triangle and not parallel to each other. Because of this, I believe the bars were binding. Now, their like a rectangle, like they should be, and the articulation is far better. I'm surprised that the total shock travel is only 3.5". = 1.5" up or down. Not much ! I can place my hands on the right rear, and push the car up & down and it moves pretty well but, on the right rear, it takes much more force to move that side up & down ?

If the suspension is still binding, I don't have a clue why ? It's either the shocks or one or more of the bars binding. I was actually hoping that one or both shock rods were slightly bent from the railroad track incident because, that would be a no brainier fix but, both seem to move freely. I don't recall if this happened with the struts on or not. Guess I'll try it.

A friend just called me saying that he went to a well known custom car builder called "Muscle Car Restoration", if fact, they are building a new "Bert Reynolds" Firebird, like in Smokey the bandit movie. They are having the same issue,.... about having one of the height adjustment collar's higher than the other side. Wow,...someone else has the same problem. Hum ?

Is this a typical situation and not to be concerned about it ? My thinking (with my pea size brain) is, yes, it should be a issue because, if both springs are the same length and tensile strength, one spring will be compressed and loaded with the cars weight, and the other having barley any on it. Is that theoretically correct ?

Let me know, what suspension set ups your using, especially if have a big block.

If I'm out of my mind on this issue, please slap me across my head, to knock some since in me. lol


Again, sorry this thread is so long but, if I'm not the only one that's having this problem, and it needs to be addressed. Thank you so much a head of time, for reading & thinking about this issue.

Kevin

(I'm embarrassed how dirty the underside is. Went through my first rain storm,....never AGAIN) !!!

(Brief story. My wife & I were going to a car show and we were on a highway. One of those rains where you could see, five miles dry, next mile, down pour. Wife said, just go. I have no wipers (don't need them right) Well, it was pouring and could not see well so, my wife has big hooters. I told her to stand up, put her boobs on the windshield, and I would drive side to side, wiping the windshield dry) hehe !

Motto of the story-Go fast and have another purpose for your woman's boobs.

http://i25.tinypic.com/33ygjn4.jpg
http://i31.tinypic.com/2cxcobr.jpg

Kevin
I'm sure you've checked this, but I had the exact same problem with my LS. I made all the measurements and adjustments during the build and really didn't have all the weight on it at the time. The RR was to high, and for that matter the RF was a little high. No matter what I did with shocks, I couldn't lower it. Several months past, and I decided that my pinion angle wasn't quite where it needed to be with the weight on the car, and pulled her up on the KwikLift to adjust it. I loosened the lock nuts on the left upper link bar and started to turn it, which was hard as hell to do with the weight on, but noticed the farther I turned it the looser it got and at the same time the RR of the car was getting lower. I proceeded to lower the adjustment on the spring, that like yours was almost to the top, while the other was at the bottom. Set it even with the other side, and turned the link until I could turn it freely by hand. Cinched up the lock nuts and hit the road. Could not believe how much better the car rode. When I changed the heim joints to the teflon ones, which I obviously had to do with the weight off the axle, I followed the same procedure, but as soon as I put the weight on it the left rear was high. So I backed off the right upper with the weight on the axle, and presto, brought it back down to normal. Something to check, anyway.

Brad W.

I assume you're talking about the pan hard bar ?

A buddy helped me out (he's the man) changed all the heim's with the Teflon and bought the new QA-1 shocks with 10" springs. We ended up using the springs off the Aldan's because the new one's were supposed to be 10" but, they were actually 10.5" and I wanted to lower the car, not add in height. After playing around with the shock collar's and the pan-hard bar, the car (I think) looks awesome in the back. I have the shocks set at 6 out of twelve.

I've just drove around the neighborhood for test runs. My buddy's shop has a alignment machine and we will adjust the chassis then. It does not seem to dog track but, I don't want to scrub the tires. The right front is apx. 1/4" higher than the left front but, we'll split the difference between the two and fix that before aligning the car. I can't believe how much better the QA-1 shocks are. I still think the left rear quarter panel is higher than the right but, with the way the car is now, you can't tell. The right rear shock collar is apx. 1" higher than the left rear, it's at the bottom. If you look at my weight in the back, and account that the battery weight's about 50 lbs, the total rear is pretty close. If I was too anal, I would put the battery in the middle of the trunk, but I won't. (dont think so,...well maybe,...hum,....na, damn,....):JEKYLHYDE

I can't give enough praise to my buddy Chad, he's the best mechanic I've ever seen and one hell of a friend. I would not been able to figure the chassis problem out without him. I'll see what happens at the shop this weekend after alignment.

I don't think it's binding any longer. With the shocks off, I could move the rear end up & down easily so, the four bars evidently are moving freely. It may have been the shocks, although I did not see any bend on the shock rod but, it doesn't take much to ruin the travel. When I'm done, I will post a pic to show the difference of before & after. It's so,ooo much better ! :D

Thanks,
Kevin

I assume you're talking about the pan hard bar ?

A buddy helped me out (he's the man) changed all the heim's with the Teflon's and bought the new QA-1 shocks with 10" springs. We ended up using the springs off the Aldan's because the new one's were supposed to be 10" but, they were actually 10.5" and I wanted to lower the car, not add in height. After playing around with the shock collar's and the pan-hard bar, the car (I think) looks awesome in the back. I have the shocks set at 6 out of twelve.

I've just drove around the neighborhood for test runs. My buddy's shop has a alignment machine and we will adjust the chassis then. It does not seem to dog track but, I don't want to scrub the tires. The right front is apx. 1/4" higher than the left front but, we'll split the difference between the two and fix that before aligning the car. I can't believe how much better the QA-1 shocks are. I still think the left rear quarter panel is higher than the right but, with the way the car is now, you can't tell. The right rear shock collar is apx. 1" higher than the left rear, it's at the bottom. If you look at my weight in the back, and account that the battery weight's about 50 lbs, the total rear is pretty close. If I was too anal, I would put the battery in the middle of the trunk, but I won't. (dont think so,...well maybe,...hum,....na, damn,....):JEKYLHYDE

I can't give enough praise to my buddy Chad, he's the best mechanic I've ever seen and one hell of a friend. I would not been able to figure the chassis problem out without him. I'll see what happens at the shop this weekend after alignment.

I don't think it's binding any longer. With the shocks off, I could move the rear end up & down easily so, the four bars evidently are moving freely. It may have been the shocks, although I did not see any bend on the shock rod but, it doesn't take much to ruin the travel. When I'm done, I will post a pic to show the difference of before & after. It's so,ooo much better ! :3DSMILE:

Thanks,
Kevin

coil overs
 

Kevin and Brad

What weight springs do you have on the front? Rear?
My LS weights 2315 with a small block and 2660 with gas and driver. 48%front and 52% rear. I have QA1 on the front and rear. I have 375 lb spring on the front but would like to soften the ride a bit. Do you have a link to a site that calculates springs for cars?

Thanks Dwight

Kevin,
He's not talking about the Panhard bar. He's referring to the four-link bars. If the bars are loaded against each other it can raise one side of the car and/or impede the free motion of the suspension.

Once you have your axle where you want it in the wheel wells (fore and aft), make sure the thrust angle is centered toward the front wheels (you can use a laser level on the rear wheels and reference the front brake rotors). Set your pinion angle with the weight on the rear axle. Now adjust each of your four-link bars a bit each way until they turn easily by hand with the weight still on the axle. When you reach a situation in which all four bars will turn easily you know the bars are not "fighting" each other. Re-check your pinion angle. If it's still correct, lock down the adjustments on all four bars (make sure the heim ends are aligned the same on each bar). Twist them all again to make sure you can still swivel each bar easily by hand. Re-check the pinion angle and you're done.
The rear suspension should now be softer and the body as level as it gets.