Is this how Ground Control coilovers should fit?

Suspension, including wheel, tire and brake.
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SteveEdmonton
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Is this how Ground Control coilovers should fit?

Postby SteveEdmonton » 16 Apr 2016 10:42

Hi all. I'm test-fitting these coilover sleeves on my 280ZX struts and not really liking what I'm seeing. I'm using clamp-on collars as the bottom stop at the moment. I want to assemble the units this way and try them in the car before welding on the permanent stops supplied with the kit.

Here's the overall picture.
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GC recommends putting the bottom edge of the weld-on stop 9 1/4 " above the top of the spindle casting. That stop is 3/16 " thick. Therefore I have bolted on this temporary collar with its top edge 9 7/16 above the spindle casting.
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What troubles me are two things. The pic doesn't show it, but the red threaded sleeve has more than 2 mm of "wobble" on the strut tube. That is, its diameter seems to be too big. The wobble itself seems like it would be a Bad Thing under driving conditions. And further, what's going to keep this red threaded sleeve from rotating when I try to set the height of the gold adjusting ring, with such a loose fit? Seems to me there ought to be some means of attaching the sleeve firmly to the strut tube, for both of these reasons.

What the pic does show is the other thing: the gap of about 13mm (1/2 inch) between the top of that same sleeve and the top of the strut tube. I don't have the large retaining nut screwed down in the photo-- it's only loose-- but as you can see, there are even more mm between it and the top of the threaded sleeve.
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I haven't had coilovers before. Is this normal, or is something wrong here?
'71 4-door
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dodgydan
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Re: Is this how Ground Control coilovers should fit?

Postby dodgydan » 16 Apr 2016 11:11

not sure of sleeve fit, these are my front 280 struts with metal threads welded on. my rears just use the pinch cooler over the shock with the red sleeve. but the sleeve fits tight. i have not tried to spin it to see if it rotates on the bench. but it doesn't rotate mounted in car.
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looking at other sleeve conversions that i have seen. some had allen head set screws to lock the sleeve to the tube. and o focus i had worked on even had electrical tape wrapped around the tube under the sleeve to tighten the fit. :shock: . what does ground control or T3 recommend? This is my rear shock
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Last edited by dodgydan on 16 Apr 2016 11:33, edited 2 times in total.
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SteveEdmonton
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Re: Is this how Ground Control coilovers should fit?

Postby SteveEdmonton » 16 Apr 2016 11:23

Thanks Dan, the picture helps. Looks like you have the same gap at the top, between the top of the threaded sleeve and the bottom of the retaining nut.

Because your front sleeves are steel and welded on, the rotation and/or wobble of the sleeve is obviously not an issue. I wondered about that before buying mine-- steel tube, aluminum sleeve-- but because aluminum is the only option GC was offering I "assumed" it must be OK.... :? With your rear aluminum sleeves being tight with your struts, though, I'm still wondering if everything is actually fitting the way it's supposed to on my setup...
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JordanTr
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Re: Is this how Ground Control coilovers should fit?

Postby JordanTr » 16 Apr 2016 11:52

SteveEdmonton wrote:What troubles me are two things. The pic doesn't show it, but the red threaded sleeve has more than 2 mm of "wobble" on the strut tube. That is, its diameter seems to be too big. The wobble itself seems like it would be a Bad Thing under driving conditions. And further, what's going to keep this red threaded sleeve from rotating when I try to set the height of the gold adjusting ring, with such a loose fit? Seems to me there ought to be some means of attaching the sleeve firmly to the strut tube, for both of these reasons.

The wobble is quite standard during install. I machined a step into my weld on sleeve perches so that the bottom of the sleeve would lightly press in. On the top side I put in some shim stock to take up the play. An alternative which I did on my rear coilovers is to drill/tap the sleeve for 3 set screws. It worked better on my rear coilovers since the sleeves are steel and not aluminum but it may be an option.
Image

SteveEdmonton wrote:What the pic does show is the other thing: the gap of about 13mm (1/2 inch) between the top of that same sleeve and the top of the strut tube. I don't have the large retaining nut screwed down in the photo-- it's only loose-- but as you can see, there are even more mm between it and the top of the threaded sleeve.

I haven't had coilovers before. Is this normal, or is something wrong here?


The intent of that top nut is to secure the insert in the strut tube--it's traditionally not used to secure the sleeves.

In the ideal situation your spring rate, ride height, and shock travel length all line up perfectly to give you some spring preload (to improve spring life/ride quality) while putting the shock at ~50% travel when the car is sitting weighted. The spring preload should hold the sleeve down and prevent it from rattling.

The problem with this coilover design we all use on our 510s is that by changing ride height we consequently change the spring preload and the shock position. Other coilovers have height adjustment independent of preload such as these S14 240sx coilovers shown below. The nut you see at the bottom changes ride height by changing the entire shock/spring position relative to the hub. The upper nuts you see are used to change the spring preload.

Image

This setup has been done on 510s before. I'd still like to do it one day but I currently have plenty of other things to work on. See http://www.the510realm.com/viewtopic.php?f=3&t=4346

On my first coilover iteration (280zx struts stock length with ZX inserts) I lowered it severely and actually ran out of travel and was hitting the bump stocks quite frequently on rough roads.

My newest setup with shortened struts/mr2 inserts gives me just a little bit of spring preload, puts the shocks halfway between bump/droop and puts the ride height where I want it. I got lucky!

On the fronts, I wanted to maximize the rim/tire to strut tube clearance so I pushed the sleeves etc. up as high as I could while ensuring I had sufficient adjustment.
Image

Image

HTH
Jordan | '72 2 door KA project | '94 240sx RB26DETT | '97 Silvia RB25DET | '90 Audi 90 Quattro 20V (DD)

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SteveEdmonton
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Re: Is this how Ground Control coilovers should fit?

Postby SteveEdmonton » 16 Apr 2016 12:04

Dan and Jordan, thanks for the help. I think I'll carry on with my test-fitting and see how it all comes together upon installation in the car. It's reassuring to hear both of you suggest that wobble-- and a gap at the top-- are not unusual.

I notice too that both of you have posted pics of clamp-on collars. Dan, your pic shows them in use on your rear struts in your car. Jordan, your seem to be on the bench. I think I remember reading elsewhere (months ago) about some guys using these "permanently" rather than the welded-on rings. Easier for sure.... Acceptable?
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funwithmonkeys
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Re: Is this how Ground Control coilovers should fit?

Postby funwithmonkeys » 16 Apr 2016 12:43

Mine also fit loosely but came with 2 rubber 0 rings that fit snugly around the strut tube. When the sleeve is slid down over the strut tube with the rings on it it fits snug with no movement. I am monitoring it to see how they wear and so far all it good. That is after 2 years.
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Re: Is this how Ground Control coilovers should fit?

Postby funwithmonkeys » 16 Apr 2016 12:45

Mine also fit loosely but came with 2 rubber 0 rings that fit snugly around the strut tube. When the sleeve is slid down over the strut tube with the rings on it it fits snug with no movement. I am monitoring it to see how they wear and so far all it good. That is after 2 years.
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Re: Is this how Ground Control coilovers should fit?

Postby JordanTr » 16 Apr 2016 14:57

Mine is also on the rear because it would be rather unwise to weld a collar onto a loaded gas shock. My rear shaft collars actually butt up against a shoulder on the shock so they really aren't going anywhere. My front perches are brazed on.

Some guys use the collars permanently and I haven't heard any failures. If you go that route, I'd suggest using emory cloth to clean the strut tube where the collar will go so you get the maximum contact area. Use Loctite 272 on the bolts and torque to spec.
Jordan | '72 2 door KA project | '94 240sx RB26DETT | '97 Silvia RB25DET | '90 Audi 90 Quattro 20V (DD)

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Re: Is this how Ground Control coilovers should fit?

Postby okayfine » 16 Apr 2016 17:29

I ran the collars on Whitebird for the 7 years I had it. Zero problems. I have not heard of any collars slipping, much less properly-prepped collars (such as what Jordan recommends above).

My GC sleeves also fit loose, they do that. They'll also clink and clank at you when you're driving through neighborhoods or rough roads at slow speeds, so you'll definitely want to shim them or do the trick with the o-rings.
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SteveEdmonton
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Re: Is this how Ground Control coilovers should fit?

Postby SteveEdmonton » 24 Apr 2016 15:35

I'm starting to think I should never tackle a project like this without somebody right there, physically available, who's done the job before. Honestly, I had no idea when I started this front-suspension adventure how complicated it would be. There are just too many unknowns for me to think my way through, by myself, along the way. :(

Here's the latest. I test-assembled my coilovers this afternoon just to see how the pieces actually fit. This was after solving the "sloppiness-on-the-strut-tube" issue by cutting thin strips from a bicycle inner-tube and using them as home-made O-rings to tighten up the fit. That part seemed to work well. The red threaded sleeves fit pretty snugly onto the tubes now.

But as you can see below, there seems to be a fairly obvious problem with the relative length of the various bits. With the adjuster all the way at the bottom, there's a gap of about 70mm (!) between the top hat and, well, the other part of the top hat. :?
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With the adjuster all the way to the top it's marginally better, but there is still zero pre-load on the spring. It's not compressed at all.
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Logically, it seems to me like one or more of these 3 things is wrong: (1) my springs are too short; (2) the strut cartridges are too long; (3) the clamp-on collars are too low on the strut tube.

However: The springs are 8", which is what Dustin at Ground Control recommended as the length most guys are running on street 510s. The strut cartridges are stock 280ZX units by KYB, and I supplied that info to Dustin when I ordered the coilovers. And the clamp-on collars are set to exactly the height that GC recommends on the (very basic) instruction sheet that came with the kit.

Obviously I could add some pre-load to the spring by moving the collar-- and threaded sleeve--up to the top of the strut tube. It could go up by about 12mm (see below). However, this would raise my ride height, thereby cancelling out a good part of the advantage of the coilover.
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I'm presuming in all of this that it is necessary to have a certain amount of preload on the spring while the unit is out of the car. I assume this because of my further assumption that the LCAs, TC rods, and sway bar will actually allow this spring/strut unit to extend this far at "full droop" position in the car. However, I realize that I could easily be wrong on this. Maybe it's not necessary to have any preload at all on the bench?

As you can tell, there are too many variables here for me to sort out using mere logic, in the complete absence of experience. Comments? Advice?
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funwithmonkeys
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Re: Is this how Ground Control coilovers should fit?

Postby funwithmonkeys » 24 Apr 2016 16:06

I know that mine have no preload. That is the way most of these kits are made.
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Re: Is this how Ground Control coilovers should fit?

Postby okayfine » 25 Apr 2016 05:57

SteveEdmonton wrote:Logically, it seems to me like one or more of these 3 things is wrong: (1) my springs are too short; (2) the strut cartridges are too long; (3) the clamp-on collars are too low on the strut tube.


This is due, in large part, to adapting parts instead of having parts specifically made for our cars.

As you can imagine, with the thousands of 510 owners having switched to ZX struts and hundreds that have switched to C/Os, there isn't a real problem with the short spring at full droop. Two ways to fix this - 1. buy longer springs. Longer spring may push the bottoms of the adjusters downward, which may interfere with your wheels. 2. buy helper springs. Also called tender spring, these are short springs for coilovers that have zero rate, just enough to take up the slack.

Trouble with #2 is, tender springs are spendy for what they are.
Because when you spend a silly amount of money on a silly, trivial thing that will help you not one jot, you are demonstrating that you have a soul and a heart and that you are the sort of person who has no time for Which? magazine. – Jeremy Clarkson

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Re: Is this how Ground Control coilovers should fit?

Postby SteveEdmonton » 29 Apr 2016 10:01

Glacial progress on this coilover project, with 2 new questions as I inch my way along. Both of them have to do with my camber plates from DP Racing. I bought them new-but-second-hand from somebody on the Realm a couple of years ago.

First: the "upper spring perch" nests properly into the top coil of my new CO springs-- but its outer diameter seems to be rather too small.
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Compare this with the drawing on the DPR instruction sheet. They call for 2.5 inch springs (ID) and that's what I've got, so I'm "presuming" this is OK even though it looks a little sketchy?
DPRacing 510 offset camber plate install instr Apr2016 EDITED.gif
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Second: In order to add caster, these offset camber plates require cutting of the strut tower. DPR's instruction sheet is adequate (apart from the obvious mistake in labeling "front of car" on this particular drawing-- it's correct on another one!).
DPRacing 510 offset camber plate install instr Apr2016 edited 2.gif
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However, I'm not sure how to actually do this without making the whole thing look like a big mess. How do the 5 new mounting-holes, which thankfully are small, line up with the 3 old and much larger ones? How have other guys "smoothed out" the profile of the cuts to the two sections of metal in the strut tower, namely the outermost ring and then also the smaller inset ring?
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For reasons of strength, I'm assuming the goal is to retain as much of the existing material as possible. However, I don't really want it to look like crap either!
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okayfine
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Re: Is this how Ground Control coilovers should fit?

Postby okayfine » 30 Apr 2016 07:32

The spring OD compared to the top-hat OD is fine. As long as the top hat has a recess that fits inside the ID of the spring, won't be an issue.

Cutting the radiused lip of the strut tower...is kinda like cutting the roof off a car. The strength the radius gives is dependent on there being a radiused lip all the way around. Once you cut it, most of the strength given by the lip is gone. Which isn't to say others haven't done it, and no one has really reported issues, but there's no real way around that design.

Looking at the adapter plate in the last picture, it would seem only one of the holes (engine-side hole on each strut) will line up. I might figure out a better way to template it if I had the parts and/or instructions, but I'd set the plate flat on top of the tower, line up the engine-side bolt hole, center the plate concentrically, then Sharpie in the cut out areas in the adapter plate onto the strut tower. Gives you an idea of what needs to be cut. How much you clean it up is up to you, but some work with various sanders, files, etc., can do the job after a fashion.
Because when you spend a silly amount of money on a silly, trivial thing that will help you not one jot, you are demonstrating that you have a soul and a heart and that you are the sort of person who has no time for Which? magazine. – Jeremy Clarkson

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Re: Is this how Ground Control coilovers should fit?

Postby defdes » 30 Apr 2016 08:25

This is what I did:
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