Coilover shock problem

[68EFIvert]

I posted a picture earlier this summer from a show I was at and I think Rick mentioned that my car looked like I lowered it. I haven't touched the suspension for the last few years but Rick got me thinking. The drivers side was a little lower than the passenger side up front and it seemed to be about 1" lower than what I wanted it to be. I recently started to have my left front tire rub when I am taking a sharp turn and going in or out of a driveway. I decided that I would see what was going on tonight and raise the car up about an inch and level it out again. I figured that the nuts came loose on the bottom of the shock and allowed it to lower down.

When I got the car jacked up and the wheels off I took some measurements and found the drivers side had about 1/2" more threads showing on the coilover than the passenger side did. I thought that was kind of weird but it got even worse very quickly. I looked at the shocks and it appears that the springs are rubbing on the shock body. Bad enough that they are taking off the metal of the shock housing. I am running a Ron Morris coilover kit so I will be sending him an email tonight and a phone call tomorrow to figure out what the heck is going on.

I wonder if the springs are going bad and causing some flex? What do you guys think?

 

[daveSanborn]

Is the cartridge centered within the spring and does it stay centered as the suspension compresses? Looking at the pictures the spring is obviously interferring with the top edge of the cartridge during compression, but is it because the spring is binding or because the cartridge isn't centered/possibly moving? What happens when you cycle the suspension with a floor jack? Interesting dilemma.

 

[Shaun]

Looks normal to me when using a really long spring. Springs don't compress in a perfectly straight line. You can buy plastic/rubber sleeves that fit between the springs/shock body to help protect the shock body from this sort of thing.

Btw, what rate spring is that? It looks HUGE!

 

[daveSanborn]

Looks normal to me. You can buy plastic/rubber sleeves that fit between the springs/shock body to help protect the shock body.

Btw, what rate spring is that? It looks HUGE!

Agreed that the coil springs appear very large. It was the first thing I noticed. We're using 450# coilover springs and they appear almost half that size.

We used TCP's coilover kit on my son's car and the springs do not interfere with the cartridges. I don't understand how it could be considered "normal" for a coil of the coil spring to "catch" on the top edge of the cartridge during compression.... please explain.

 

[Shaun]

Agreed that the coil springs appear very large. It was the first thing I noticed. We're using 450# coilover springs and they appear almost half that size.

We used TCP's coilover kit on my son's car and the springs do not interfere with the cartridges. I don't understand how it could be considered "normal" for a coil of the coil spring to "catch" on the top edge of the cartridge during compression.... please explain.

Sorry Dave, I edited my original post right as you were posting this one.

Springs bend when compressed. If the spring is long enough, and the gap between the spring and the shock is small enough then they could rub.

 

[68EFIvert]

The spring is the stock "street" spring rating that Ron sells with the kit. IIRC it is 450 lbs. I have always thought that it was a little heavy for the front suspension to have a spring that firm or maybe I have the wrong spring. Is there a way to tell what rate spring you have? I assume it is possible to switch to a spring with a smaller diameter coil but I have no idea what brand that would be. My shocks are QA1 and assume the springs are the same brand.

What brand springs do you use with your new kit Shaun? I assume they would be a drop in on my QA1 shocks. Could I use a shorter spring?

 

[daveSanborn]

Linked is a coil spring rate calculator. The number of "active" coils is determined by subtracting the "end" coils since they are stationary and don't provide any input on the rating of the spring.


http://www.stockcarproducts.com/pstech10.htm


Coil springs would only be interchangable if the diameter of the spring remained the same... or at least enough that the upper and lower spring mounts would create a proper seat for the spring.

 

[68EFIvert]

Thanks for the link Dave. I'll take some measurements and do some calculating this evening. It almost makes me want to just convert to Air springs and say screw the spring/shocks. If it didn't cost $3-4k to do it I would be all over that.

 

[Shaun]

450lbs is what we use in our Sport setup for 65-68 small block cars. Later year (heavier cars) get higher spring rates to give the same feel. With our motion ratio of .76, 450lbs works out to be pretty much the same as a 600lb conventional spring, pretty heavy for street cruising. Our Street setup for 65-68 car uses 375lb springs for small block cars. It's motion ratio dependant though so what works on our system may not work on his if the MR is different. The harsh ride is most likely coming from the off the shelf shocks though...

I'm ASSuming the RM coilover uses a 2.5" spring. If so, you can buy any length in pretty much any rate in 25lb increments from us or tons of places. You won't get the best ride you could if you don't match the shock valving to the spring but its a start and cheaper than replacing shocks and springs.

Air bags? Ewwww....

 

[Midlife]

For the uninitiated (me!), could you define motion ratio?

Thanks.

 

[Shaun]

For the uninitiated (me!), could you define motion ratio?

Thanks.

Motion ratio is how much the wheel moves compare to the shock. If the wheel moves up 1" and the shock shaft also travels 1" then the motion ratio is 1:1. This is ideal but due to packaging most cars just get the highest number they can. The higher the number the lower the spring rate required to control the same weight and the more of the shock is used.

 

[stangg]

I hopes ok to cross post from the other place...

Darreld, do you remeber posting this at the other place a few years ago...

"Ron Morris said if you want to go lower just move the lower nut down until you get the desired ride height. Then when you put the car back down after adjustment just guide the springs into place. They will actually be free floating while the car is not under load. That seems weird to me but since I don't plan on taking any Dukes of Hazzard jumps I am sure it would be fine. My current setting on the springs in the low side of the spring is 4" from the base of the shock (not the mounting point of the shock but where it is the same diameter of the threaded portion). "

My response then was...

"I recall you mentioning this in a previous thread and it's been bugging me ever since... Why would Ron Morris ever want to provide the opportunity for the springs to come loose? This is a design flaw in my opinion. If I recall correctly, the spring hat has a slot on it so it can slide out without removing the shock. If the spring drops enough, could the hat possibly fall off? (unlikely but possible).

With a little better engineering I'm sure they could come up with a better solution. Looking at your pictures, the lower shock mount could probably be shortened an inch or so which would result in lowering the chassis better than a inch or so. This might allow you to keep tension on the spring at all times by cranking up the adjust nuts another inch or so to take up the full extension slack. With the lowered - lower mount, you'll probably be able to get close to your desired ride height. I know your not planning on any jumps, but unexpected things do happen. For that kind of money, I'd expect a bit more out of them."

Today's response ---
Now I'm wondering if the spring fell out of the upper perch at some point and thus causes the spring to sit at an angle and caused the rubbing... You wouldn't have need to do do any jumping for this to happen. perhaps some extreme low speed cornering into a raised driveway or something... just enough to unload the suspension.


I've hated that system (more so their reply how to lower the car) ever since you posted that thread... it seems to easy to get into trouble with it. Also, take a look at the top of the spring hat for damage, if it did temporarily slip out along the slot, then there should be witness marks on the top of the hat...

 

[68EFIvert]

I am reminded of our discussion every time I jack up the car and think that just isn't right. That is a great idea to either drill holes lower on the lower shock mount or another hole up higher on the upper mount. I wonder if that would cause any adverse consequence? What is your opinion Shaun?

I figure if I drill another hole 1.5-2" higher on the upper mount I could remove any slack from the spring in its resting position i.e. on jack stands. I still haven't heard back from Ron yet but he is usually a few days on getting back to people. I noticed that QA1 sells springs that have a 2.5" seat on the top and bottom but flare out to 4" for the main length of the shock. That would eliminate the rubbing issue I would think. The other thought would be use shorter springs but I fear that option would open up a can of worms. If I put in a shorter spring and already have problems with the spring not seating fully when not under a load I will be making the problem worse.

 

[68EFIvert]

I did some measuring on the springs. They are 2.5" id and about 3.6 od. The spring is just over .5 thick and 12 in long. I did some calculations on the site you gave the link to Dave and they appear to be about 425-450 rates. It has a wide range of ratings by making a small change in the input data. I have to feel that they are 450 springs since Ron told me that from the start. I was also wondering what progressive rate springs would be like with this type of setup. Have you tried any of those Shaun?

 

[Fast68back]

I posted a picture earlier this summer from a show I was at and I think Rick mentioned that my car looked like I lowered it. I haven't touched the suspension for the last few years but Rick got me thinking.

Made ya look....

 

[68EFIvert]

I think I figured out my problem. First off my springs are 12" 400 lb coils. It is nice they were labeled on the side of them. I think my problem was not making sure the springs were seating properly in the holders of the shocks when I lowered the car. The springs had about an inch to an inch and a half of play before they would seat into the springs pockets. After I raised the car to its final ride height today I lowered it the way I always do and then decided I would double check that they seated in there. Both sides were off and were sitting on the edge of the spring seat. This would cause the spring to not move parallel to the shock and I believe caused it to rub.

I have the car sitting a little higher now. It is 24 1/4" from the fender lip to the ground. Before I adjusted the suspension it was about an inch lower. I will drive it for a bit before I do a final adjustment. If I have to modify it I will do so from the rear.

The good news is I no longer rub the tire going in and out of my driveway and I actually think the car handles better. I wonder if the springs have always been out of their pockets. I do think it is a design flaw that they don't seat all the way down. I may drill the holes in the shock mounts so that I don't have to have play in the spring. If I moved them 1-1.5" I would not have any problems. I guess that is another winter project.

 

[Shaun]

It isn't uncommon for the spring to not be fully seated when the car is at full droop. Certain setups will have this happen. It is however NOT ok to just have things flopping around in there.

The correct way to deal with it is to install helper springs like we do should the spring rate/vehicle need it:

The cheat way of dealing with flopping springs is to zip tie them to the top cap of the shock. This only works of course if the top cap is secured to the shock somehow. The spring will then hang in the air when at full droop and it'll use the shock body as a guide to the lower seat when the car is lowered back down. Almost a free mod but not the correct way of doing things.

Even with all the right parts on there I have still seen some minor rubbing on our threaded shock bodies. When you are hammering parts around a race track pulling over 1G things move around a little. Re-looking at your pictures though its nothing like as bad as you are getting.

 

[Shaun]

The other thought would be use shorter springs but I fear that option would open up a can of worms. If I put in a shorter spring and already have problems with the spring not seating fully when not under a load I will be making the problem worse.

Won't be worse, you'll just have the same problem further up the threaded sleeve...

 

[68EFIvert]

So how do I get myself some of those helper springs? Do you have them on the website or do I need to call you go place an order? Thanks Shaun!

 

[Shaun]

So how do I get myself some of those helper springs? Do you have them on the website or do I need to call you go place an order? Thanks Shaun!

I don't have those parts online so I'll send you a PM.