Front passenger coil over?

[Alex]

I'm playing around with front ride height/diffuser height at the moment.

Adjusting the driver side coilover is easy - make a change, drop it back on the ground, bounce it, and see what happens. Passenger side is being a real bitch though - for some reason it's taking me almost 3 times the adjustment to accomplish movements in ride height (i.e., for every 1 turn of the adjustment ring on the driver side, I need to turn the passenger side like 3x to get a similar change).

Also, it's almost like my passenger spring is binding and wedging itself onto the spring hat. On the driver side, if I put the adjustment&lock rings in the middle of the shock body thread and jack it up, the spring and spring hat become loose and flop around (as they should). On the passenger side, at the same rough point (half-way) the spring hat is still tight against the top of the shock, and the spring is tight against both the hat and adjustment ring. It only loosens up and freely flops around (with the spring hat) when I get down to like 1/4 of the thread remaining (roughly).

Springs are the same (height, coils, part number), shocks are the same, compression/rebounds the same, so I'm stumped why the passenger side is ????binding???? and requiring 3x the adjustment of the driver side (And why the driver side spring and spring hat flop freely when jacked up (as they should), but the passenger side remains wedged together for most of the shock body thread?

Right now I've got a roughly 3 3/4'' front ride height (for rough alingment and body fitment purposes) .... the driver side adjustment ring is just below the mid-point on the threads (roughly), whereas the passenger side adjustment ring is all the way at the top with 2 threads remaining. If the car is roughly 50/50 balance, then why is the passenger side fighting me?

I'm missing something, just cant figure out what that something is

 

[Randy V]

Not owing an SL-C I can't relate to the suspension like I can on my GT40.

But.

Is it possible that you have a rear spring on the Driver's side front?

What about your rear ride height?

Remember when you go to lift one corner, the car is trying to act like a teeter-totter and the opposite corner is trying to go down. The other two corners will pick up weight as well, but usually not as much.

Are there any sway bars involved here? Disconnect them while making these adjustments and then set them neutral once the ride height is correctly adjusted.

 

[Alex]

No sway bars

Rear ride height is even (4'')

My front ride height is also even (3 3/4''), however, like I said, I need a lot more adjustment (I said 3x initially, but looking at it again today it's more like 2x) on the passenger side than the driver.

Coil count and part numbers are matched on the front, and same with the rear (so I don't have a rear spring in the front, etc...)

compression/rebound on the shocks are set at the same point (incase that's effecting anything)


right now the weight balance (driver to passenger side) looks even. In the rear, if I adjust the driver side it moves accorindgly. If I adjust the passenger side, same thing. Front driver side, same thing. It's just the front passenger side - takes soooooo much more adjustment to get it to do something and I can't figure out why.

I ~think~ the key to understanding what's going on (although I don't understand it) is the spring hat/spring relationship.

On my cobra, I have DA konis on 4 corners. If I jack up the car on one side, when the suspension de-loads the spring comes loose fomr the spring hat and flops around.

On the SLC, in the rear or driver front, if I jack up the car same thing - spring hat and spring come loose and flop around. However, on the passenger front, if the adjustment ring is half way up the shock body (or further) and I jack it up, the spring seizes onto the spring hat and won't come off of it and flop around unless I spin the adjustment ring downwards a signifigant margin. And by seized, I mean it's seized on there - for example, if I want to spin the spring further upwards the shock body, I can't turn the adjustment ring - it's too tight - I just grab the spring itself (with the car jacked up) and turn the spring (which causes the adjustment ring to move upwards). Need to move spring down - same thing - I turn the spring since the sprng hat and adjustment ring are seized onto it, and then around the half-way point the spring hat flops off and the spring is free to flop around

That's got ot mean something, I just don't know what.........

 

[Randy V]

I don't know if it's just because I've had 2 16 hour days in a row and I'm tired or what... I'm just not visualizing why or how the one front shock / spring can be behaving differently from the other..

How about some pics. Particularly that show the spring hats and adjusters (top and bottom) ....

Are you sure that both shocks are mounted in the same manner/location?
No interference with the Spring Hat and the shock/heim (hair pin holding the hat in position)... ???

I'll check back tomorrow. Hopefully when I've had more than 3 hours of sleep... ((sigh))

 

[Alex]

No interferences that I can see between anything.

Will try to post pics tomorrow to illustrate what I'm trying to say.

 

[Dave]

Mark the spring perch location on each of the front shocks and swap the shock and/or the spring from side to side to see if the problem migrates with the shock/spring.

Regardless of part numbers, I'd pull the springs and make sure they are the same height and perhaps even test them. Also make sure your shocks piston are seeing the same length and delta with each other.

 

[Will Campbell]

Mark the spring perch location on each of the front shocks and swap the shock and/or the spring from side to side to see if the problem migrates with the shock/spring.

Regardless of part numbers, I'd pull the springs and make sure they are the same height and perhaps even test them. Also make sure your shocks piston are seeing the same length and delta with each other.

Testing the springs, or at least verifying that they have the same spring rate is good advice. Some springs only have a paper tag on them to show spring rate, some others have a color coded paint dab or an actual rate printed on the coil, but the better ones have a test range engraved on one of the tangs. Loosen the spring or remove it to examine both tangs to see if they are marked, and validate that they are the spring rate you expected (check both sides).

If they aren't marked or you don't trust the numbers, find a local race shop with a spring checker and validate the spring rate. Should be cheap-to-free to do, and will rule in or out the spring. The spring checker will also measure free height, which is what Dave is talking about above.

It's good that you checked the shock settings, but broken shocks out of the box aren't unheard of- so you might remove the shock and validate that there are no sticky points in the travel, and that you get the full range of motion. For setup purposes with adjustable shocks, always set the shocks to max soft, so as not to interfere with the setup process. You must reset them as needed after the corner weights have been set.

Swapping sides is also a good idea to see if the problem follows the coilover, or stays on that side. If it stays on the pass side, then you have a problem with the control arms, or how they are mounted to the chassis (assuming the chassis is straight).

If necessary, if you don't have the RCR front lift kit, you can swap the rear springs out for the fronts just to see if you can setup the front equally (put them back when you are done with the test, of course).

If everything else checks out, validate that the chassis is square.

If you can't find the problem after doing all this, do it again- it's in there somewhere.

 

[Alex]

for maximum softness, is that compression/rebound all the way to the - or +?

 

[John Milmont]

Alex, have you taken off the shock and spring entirely and moved the control arms by hand to check for 'stiction' or binding?

 

[Ian Anderson]

Alex

Take complete Shock and spring unit off the car
Swap with the other side
Retest - if your problem follows the shock spring unit pretty dam certain something is faulty.

Saves having to pay out to have someone check it

Ian

 

[Will Campbell]

for maximum softness, is that compression/rebound all the way to the - or +?

Set them to the max "-" position.

Checking for binding in the arms without the coilovers is a good idea too, as mentioned above.

 

[Howard Jones]

Take the shock off the car and remove the spring. Set to min rebound and compression settings. Now push the rod in and out of the body. It should feel the same resistance throughout the stoke. If it binds up at some point then the shaft is bent. If it is generally stiffer than the "good" side then it is possible that the shock valving is sticking some how internally.

I would do the same to the "good" side and see if there is any difference. You can also check all the rod ends and see if one is bad. Then swap spring and hat between shocks and look for different fit.

The problem is right in front of you, you just need to swap some parts around in a methodical way and find the bad one.

 

[Dalton Veitch]

"The problem is right in front of you, you just need to swap some parts around in a methodical way and find the bad one."

This sounds logical. Can also apply to marriage or lots of other things.

 

[Mark]

Is the washer on top or bottom of the spring?

 

[Alex]

All good ideas. I'm currently working on several things, so I'll have to investigate further at a later point - I was just hoping something would jump out from my description.

Right now I'm working on aligning the clips, so I can set the proper ride heights and see how everything works and looks and catch/fix flaws here and there.

I'm ending up with 4 1/2'' ride height front/rear ..... I have no clue how you guys run 4'' on the street - the tire is almost right ontop of the body, lol .... 1 bump and bye-bye wheel arch, heh. 4 1/2 seems the right balance between looks and functionality (bumpity bump bump)

Is the washer on top or bottom of the spring?

not sure what washer you're referring to - if you mean the one by the adjustment ring, it's on the bottom of the spring (between spring and adjustment ring)

 

[Alex]

Updates. Mmmmm.

rear ride height even at 4 1/2'' each

I arbitrarily left 10 threads showing on each coilover. Driver side (after settling suspension by jumping in the cockpit several times) was 4 3/4''; passenger side was 4 1/4''.

I switched assemblies (everything; shock, spring, hats, etc...) around (driver to pass, pass to driver), settled the suspension, and once again driver side 4 3/4, passenger side 4 1/4. So that rules out anything in the shock

When I watch the LCAs as I jump in the cockpit, both are moving evenly. Also, when I remove the shocks from the LCAs, both LCAs droop evenly towards the ground, so neither is binding. I can't imagine what removing the LCA would accomplish (other than give a gigantic headache putting those washers back in, lol!, been there, done that).

This is very peculiar - the chassis is balanced fairly evenly so there should be no reason why I can't adjust each coilover evenly.

From the above results one might say 'well, the d/s is binding, that's why it's so high', but it isn't. It's acting as is (making noticeable changes with each adjustment) ... the passenger side takes more effort (turns on adjustment ring) to make changes, and after a certain point (roughly half-way point) when I jack it up and deload the suspension, the spring stays seized onto the spring hat, as opposed to flopping around happily. Hmmmm.

what is the SLC front geometry ride height based on?

have you actually got the scope in the shocks for raising it say for instance 2" above what its has been designed around and still retaining ample droop?

Can't answer that, but I don't think it matters - it's a case of the passenger side not acting as I think it should be (and the driver side acting normally)

 

[GARY_S]

is your garage floor level?

 

[Fred W Ballinger]

If the problem stays on the same side after you have swopped all the bits from side to side one of the coilover mounting brackets must be in a different place from the other side?

Cheers

Fred W B

 

[Will Campbell]

Alex,

It just occurred to me that you may be chasing a problem in the rear suspension.

For example, jacking any corner in the car will have an immediate effect on the opposite corner. I know this because I've spent many an hour chasing a setup around the race car. :embarassed:

Can you validate that the setup you presently have in the rear is actually correct?

An easy way to see this is to borrow a set of scales from one of your racer buddies. You could use mine, but you'd have a bit of a drive to get here from Canada, eh?

Hang in there- it will become clear eventually.

 

[Alex]

suspension brackets are mounted in the same places, nearest as I can tell from measuring.

Alex,

It just occurred to me that you may be chasing a problem in the rear suspension.

For example, jacking any corner in the car will have an immediate effect on the opposite corner. I know this because I've spent many an hour chasing a setup around the race car. :embarassed:

Can you validate that the setup you presently have in the rear is actually correct?

An easy way to see this is to borrow a set of scales from one of your racer buddies. You could use mine, but you'd have a bit of a drive to get here from Canada, eh?

Hang in there- it will become clear eventually.

same springs on both sides of the rear (650), same shocks. I can pull them off later (just loosely bolted) to compress to verify they're fine, but I suspect they are.

The only 'unusual' thing I can think of in the back is that when I jack it up from the middle, the passenger tire leaves the ground several strokes before the driver side does.