Xsta Z 28

iTrader: (2)

News to me, two cars with LCARB, and the rear(s) sits no different, I don't see how the location of the control arm mount can raise or lower the car . . . . since the bracket has no effect on the location or length of the spring.

JasonWW

iTrader: (2)

On a static vehicle, there should be no leverage. When power is applied the rear might rise or dip depending on different factors, but the normal ride height should not change. In fact you could remove the LCA's with the vehicle on a lift and you will not see any change of ride height at all. It has no effect and if you are measuring a ride height change after rel. brackets it must be due to something else.

With stock LCA's you need to loosen them any time the angle has changed (rel. brackets, lowering, raising, etc...) so that the rubber isn't put in a bind. They should then be retightened with the car at it's normal ride height.

Maybe your measured ride height change had something to do with that or did those vehicles have poly bushings?

Changing the pinion angle could effect the ride height. If you point the rear axle's nose down, it rotates the whole unit and causes the spring pads behind the axle to move up a little.

Ultimately, it's the spring that sets the ride height.

00PewterSS

iTrader: (3)

[QUOTE=JasonWW]The Eibach rear springs have a bad reputation for being too low and soft in the back. By far the easiest thing to do is add some simple spacers.


My car was 1/2" lower on the right rear and I was going to make some spacer to bring it back up to height. I saw this suggestion and figured it was worth a try. I bought some and installed last night. I am confident they will stay in there and not move and I raised that corner up 1/2". It also raised the LR up a bit also. My main reason for raising the rear was during an extremely hard left turn I got tire to quarter lip contact. This was with 295 tires on the rear.

My only concern and only reason for now wanting to do this is that it eventually will wear the coating off the spring. The outside of the spring is was takes 90% of the load. If it corrodes or gets chipped it could lead to spring failure. Simple cheap fix I appreciate the suggestion. It could to 20 years for it to wear the coating off, who knows...

Brian

JasonWW

iTrader: (2)

I'm not sure what you mean by the outside taking 90% of the load.

As far as corrosion, I think you are way over estimating things. 1967 chevy pickups use coil springs in the rear that get rusty almost from the start and those buggers are still going strong. When has anyone seen a coil spring fail due to rust or any other reason?
I'm not saying it isn't possible, but they are extremely strong an durable. I have no doubts about their durabilty.

Ojustracing

iTrader: (4)

Im from the great State Of NY and they use nothing but salt on our roads in winter. But I do see broken coil springs in my shop on a regular basis. Gm cars are better than the fords, But i get a broken coil springs cars in about once a week. Im not talking 30 yr old cars either. 99 to 96 with them broken. They are bad enough in Ford taurus that they issued a recall for the springs in heavy Rust belt area's. later John

JasonWW

iTrader: (2)

Oops, I never considered other parts of the country. If you live in those areas where they salt the roads you may have a problem with the coils breaking, but I don't think that a metal spacer would increase the chances of that happening. I'm in Houston, so we almost never see icy roads or snow (huh, what's that? ).

If you have powdercoated springs, try using the rubber spacers. You have to use more, but they shouldn't damage the powdercoat.

I personally use modded factory springs and they are just raw metal. I did paint them just to make them look good. Both the metal AND rubber spacers will squish enamel paint. Lacquer is more durable, but I think powdercoat is WAY more durable.

My bottom line is that if your springs start to have rust flaking off them or look like they are not safe to use, just replace them. Errr on the side of caution. As much as this whole website is for car nuts, I doubt anyone would let their springs or other parts of their car get so rusty and neglected, that it would fall apart or break. Now, most other people (like the Ford taurus owners ) just don't give a damn and drive their stuff till it breaks or falls apart. I could definetly see that happening.

00PewterSS

iTrader: (3)

What I mean, I'm not sure if I can explain. The spring works in torsion. Most of the load of the spring is on the outside of the coil because of this. For example a hollow stabilizer bar will have nearly the same torsional rigidity as a solid bar because the material in the middle of the bar doesn't see much strain. So if the outside of the bar is damaged by corrosion or otherwise it causes a high stress concentration and it can fail.

I like the metal spacers better and I will just keep an eye on them to make sure they aren't gouging the spring. I work for GM and have run lab tests for suspension modules. If the powder coating is damaged or there is a defect in the outer part of the spring they don't survive as long.

Again thanks for the cheap suggestion!
Brian

JasonWW

iTrader: (2)

All right, I see where you are going. Most people aren't as technical when it comes to how a coil spring actually works. (for those who are interested) The coil spring is just a more compact version of a torsion bar. If you unwrapped a coil spring you'd have a metal rod about 5ft long (give or take?). It's whole load bearing ability is based on the rod twisting. One end is fixed and the other is twisted by the weight of the vehicle. Some cars and trucks still use torsion bars includind the newer GM 4x4 trucks as a coil spring would get in the way of the half shafts on the front.

Anyway, if a small spot on the exterior of the bar got corroded away it is not going to effect the torsional rigidity, is it? For sure it is a small weak spot, but what causes most springs to fail? I'd really like to know.

As far as the metal being gouged, I don't think it will happen. The metal spacers are made of aluminum and the coils are hardend steel? Should there be any gouging of the spring? Help me out Brian, I could use your expertise.

All in all, I have no worries. I also haven't had any rust on the springs in the year I've been using them. Do you think there is any real reason that the springs might be fragile enough to break later on? How much later? 2 years, 20 years?

We need more people on these forums who work at GM and run lab tests for suspension modules.

00PewterSS

iTrader: (3)

Oh I don't think they will gouge the metal just the coating. With the coating gone it will eventually rust. This might be of no concern at all, it all depends on how much strain is on the outside coil of the spring.

Anyway, back to what makes springs fail. The spot on the outside would not change the torsion of the bar. What it would do is cause a large stress riser at that location and cause it to fatigue much faster. Springs fail under fatigue and if there is a stress riser they will fail much faster. A polished spring vs. a spring with a rough surface would last longer. A lot of factors determine how long the spring would survive, some springs with surface imperfections are in a service environment that would cause them to have a nearly infinate life.

I don't run lab tests anymore. My current job is to determine what loads are to be used to run the lab tests for all of the the GM car programs (except GTO, Lecerne and Deville. In other words if we can use math or need to collect loads to drive lab tests.

There a lot of experts on here and I wouldn't consider myself an expert on anything, but I know some stuff... lol
Brian

JasonWW

iTrader: (2)

Hey, could you take a look at this thread?
https://ls1tech.com/forums/suspension-brakes/329964-anyone-sell-1-drop.html

Trackbird was sharing some concern about the spacers.
Does he have a valid point about the spring wanting to fracture? I don't think so, but maybe you have some additional insight.

00PewterSS

iTrader: (3)

Good question. Springs are intended to work in torsion so any other load implied to them wouldn't be good. But in this case the coils you've jammed the spacers between keeps the coils from moving relative to one another. It is a viable concern, though since the coils are supposed to be twisting I can't really say whether this would adversely affect them.

Brian