Coil Over FAQ Question

[Twoeightnine]

{In response to JohnC's Coil Over FAQ:}

Good afternoon sir.

Always good to see your comments. Facts are good. Disscussions are good for development but I'm building a nice Z, not trying to re-invent the wheel.

My questions are.. the 5.25 dimension that you mention. Is that good for 8 inch spring, 10, 12? Are these dimensions published if they are different? Surely they are.

I have done the math but, with such a tight fit, I would like to have the threaded collar length right with little left to extend beyound the adjustment nut.

Minus the clearance gains, did you like the performance of your 8 inch springs? Im leaning towards the eights for wheel choice.

My struts are ready to cut, want to weld only one time.

 

Many thanks for all that you have already taught.

 

Twoeightnine.

[Twoeightnine]

Howdy to all.

 

The above post was in response to information on one of Johnc's FAQ pages concerning coil over questions. It was probably posted incorrectly and landed here. The questions still remain as I have not seen any specific dimensions published.

In basic, converting first generation struts to adjustable coil overs seems a fairly straight forward task. I have even seen photographs (Brians Garage) of it being performed. The method of locating the welded ring is another story.

 

Has any one published dimensions as to where the welded ring that the threaded collar rests on should be? If using a twelve inch spring, could one assume to move up the strut this dimension two inches for a ten inch spring? And four inch for the eight?

And most important, are all involved happy with the performance of an eight inch spring.

I have decided on the 245/45/17 tire option and feel that an eight inch spring will not be required. however if eights work fine at 225F 250R, It wouldn't hurt to have options for the future. Right?

Thanks to all,

 

Twoeightnine

[2126]

289,

 

Unless you want your Z to sit high or have your rear wheels sitting out further than necessary, you will want the 8" free length springs in the rear. The 10" units will be fine for the front but not the rear! Been there done that. I have 235-40 x 17's on 9" wide rear wheels and the 10" springs will be a problem...trust me! Also, if you contact Ground Control, they may provide you with the installation sheet for their coilover kit, that illustrates the required placement of the threaded collar. Of course tell them you lost the instructions...if you know what I mean!

[Twoeightnine]

2126

 

Thanks.

I take it that you have the 8 inch on the back?

Are you not running a 2.5 dia spring?

Are you happy with the rear spring?

Whats the rate?

Any bind?

lowered?

 

I have seen many a post claiming 245/45/17 with 12 inch spring.

Also i hear complaints about ground controls lack of instructions.

Have you tried it?

 

Any one?

 

Many thanks

[JMortensen]

I don't know if I did mine the "right" way, but on my first set I mounted the collar so that when the spring perch was all the way up, and the strut was fully extended, the spring was touching both the perch and the top hat. That's basically as high as you can put the collar before any further adjustment starts preloading the spring.

 

The second time around I realized through years of experience that I had been running the front 1" lower than the back, so I lowered the front spring perch 1" from where it had been on the first set of struts.

 

Like I say, I don't know if that is technically correct, but it worked fine and I was able to get the height I wanted. If you're really in doubt you can always mount the collar lower and get some longer threaded tubes.

[Twoeightnine]

jmortensen

 

Got to love it when one hears common sense!

 

Being that the stock tubes/springs have some preload, i assumed that the new coilovers would require some as well.

Being that I have significantly raised the spring rate, up to snug should be a great starting point! Good call!

Longer collars w/ about 2 inches or more below the adjustment nut?

Sounds like it may wind up landing pretty low on the strut, but not a bad thing.

I think that the long collars are eight inch which would "technically' allow for a change to a shorter spring later as well.

Good stuff.

I feel better already.

Any one else have a comment on eight inch rears at about 250 rate?

 

Thanks jmortensen. Bulls eye!

[JMortensen]

If you search I think you'll find that an 8" 250 in/lb spring coil binds before the strut hits the bumpstop. Obviously that wouldn't be the case with the car lowered, but I think with 250's you should technically have a 10" spring.

 

Your coilovers don't require any preloading whatsoever. The obvious next question is what if I go over a bump and the spring falls off the perch. Well, most manufacturers drill holes in the top hat. Run a zip tie or some safety wire through the hole and around the spring and that will prevent the spring coming off the top hat (which in realitywould take a Dukes of Hazzard style jump, BTW). If the spring comes of the bottom perch it will seat itself as soon as you hit a bump. I've experienced that when I jacked the front end up and wasn't paying attention when I set it back down. Drove down the street a ways and "BONG!" the spring set itself...

[Twoeightnine]

Thank you jmortensen.

 

I had noticed, in what I believe was one of your posts, the tie wrap mod and the "do not concern yourself with the loose spring" issue. I agree that with the right insert, and not going completly airborn, that the spring will never see itself flop about unless jacked up.

In my time asa NASCAR crew member I do remember seeing many a flopping spring when they were on the jacks. Tight spring rates though!

Dont think I want to push a spring rate to 300 just to hang an eight inch spring.

Am looking for the elusive "balanced" street brawler/cruiser.

Shes apart, want to suspend first and then move on with the rest.

Thanks for the heads up. I'll search for the happy factor on the eights but see that a tight tail is probably required.

 

Much apreciated,

 

Twoeightnine

[DaleMX]

I am going to be installing my coilovers soon. 10" 225 lb per in. I figure that the car is about 2800 so about 700 lbs on each spring. So 700 / 225 = 3.11" of spring compression at rest. I have the 5" threaded shafts so I was going to place rest position at about 2" down on the threaded shaft from the calculated top of the threaded shaft. That should give me enough room to lower the car an inch or so.

 

Does that sound right?

[Twoeightnine]

DaleMX

 

Sounds like what I have learned, as long as your two inch dimension that you spoke of is with the spring at rest?

Doing yours anytime soon?

The 10 inch length seems to be the pick in the mid 200 rates. is that what I am gathering?

My car is sitting there staring at me waiting for the springs.

If I beat you to it I'll let you know how it goes.

Unless I hear otherwise by monday, it will be 10 inch 225F/250R with an extra long collar kit set at approx 2.5 inches below the adjustment collar snug on the perches at rest.

Any objections?

 

Thanks to all.

 

Twoeightnine.

[2126]

I believe the deciding factor will be the width of your wheel. If you plan to use a wheel no wider than 7" or 8" you probably can use the 10" springs!!? Mine happen to be 9" wide rear and 8" wide front. Yes I have the narrower coilover springs and yes I have the 8" springs in the rear (275 lbs rear and 200 lbs front). I'm very happy with my setup and no I have no binding issues. Yes my Z is lowered.....probably as low as anyone would care to lower an early Z. I have just under 4" clearance at the front cross member. No going over speed bumps in my Z...that's for sure. You can see my pics on this site or on Classic Zcar Club site (under 240ZX).

 

2126

 

Thanks.

I take it that you have the 8 inch on the back?

Are you not running a 2.5 dia spring?

Are you happy with the rear spring?

Whats the rate?

Any bind?

lowered?

 

I have seen many a post claiming 245/45/17 with 12 inch spring.

Also i hear complaints about ground controls lack of instructions.

Have you tried it?

 

Any one?

 

Many thanks

[Twoeightnine]

2126

 

Thanks for the shout!Agressive set up. I'll take a look at the pics in a moment.

 

The lowering does take care of the bind issue. Yes?Glad to see you chim in in the happy zone with the eight inch.

I want only one inch down, old school, sports rod.

Still, offset dependent, 245/45/17 has been hung on the 12 inch coilover.

Wheel style is the deal. Yes? Thats for another thread.

I very much apreciate your input. I just want to begin very soon and want room to grow. Looking for balance, bang for the buck, and a quick build.

Have the budget, not so much the time.

I'll give you a shout back after I check out you pics.

 

Many thanks for your time. Greatly apreciated.

[440man]

Man, This is great stuff. I was just getting ready to post a question regarding measurements between the top inside of the tire and the coil spring on stock setups as well as with coilovers but it sounds like there aren't any clearance issues with 7 or 8" wide wheels with coilovers, correct?

 

Hey twoeightnine, I'm right there with you on the desired set up. I may want to go 2" lowered. I have the same problem with time. Would you do me a big favor? When you have your setup complete, would you share your parts list with me and maybe a couple of pics? I would greatly appreciate it as I'm ready to start mine as well!

 

Thanks again Jmortensen, DaleMX, 2126 & twoeightnine for some great info.!

 

440MAN

[Twoeightnine]

Howdy 440Man.

 

I have built a few rods in the past but not a Z. I can certainly thank jmortensen for tossing out the required info. Info good.

Knowing that the spring required little or no preload made the task a breez.

The fact that I intend to lower the Z only one inch makes it even better.

No tubes to cut, no insert procurment issues.

I'll tell you , however, when it comes to wheels it gets real interesting. Basicly the offset of the wheel makes all the difference. That is for another thread as well. "Search" and you will see what I mean. There are a gazillon posts, mostly containing theology, on the subject. Some want their tires in the well, some out. one thing for sure is most folks want as much rubber as possible. If you are staying with a modest tire and install 2.5 inch coil overs, you would be hard pressed (barring a radical wheel design) to hit anything. The stock springs are the problem. Their big!

I will order on monday and be more than happy to share. The parts that I will start with are readily avalible. Should not be a problem. Do some searches on your lowering issue. It's straight forward as well but very specfic.

 

Thanks to all.

 

Twoeightnine

[Twoeightnine]

Hey 440Man.

 

Check out Brians Garage.

The part list is in there.

I'll let you know how it goes.

 

http://www.geocities.com/bry593/coilover/coilover.htm

[440man]

Thanks 289, I look forward to hearing from you!

 

440Man

[Twoeightnine]

Guess I didn't say which monday!

 

Suspension on the way, Z on the stands.

 

If you beat me to it, let me know if had any specific problems.

 

I'll photo the process and pm them if you would like.

 

good luck.

 

 

 

Twoeightnine

[440man]

Sounds great 289. I'd appreciate pictures of the process. You can send to lbo730@bvunet.net

 

By the way, I don't remember if you were working on a 240 or 280, but as you may see on some of the other posts that the Brians Garage parts list won't work for the 280. The 280 requires the 2.17 i.d. sleeves.

 

Look forward to hearing from you.

[Guest 73LT1Z]

I need to fix my front suspension (struts/springs) and have searched, read this thread, & also the Brian's garage link. Looks like the only 280 procurement issue is the stop with the 2.17" ID. Any thoughts on exhaust pipe here swaged out a little or does the stop need to be larger in diameter than exhaust tubing?

 

I also noted some of his parts links were not valid part numbers, and by searching here, our member Here Comes Trouble linked this stuff at A1 racing.

 

COK12452-H

5" COIL OVER SLEEVE, SPECIAL ORDER, FITS STRUT HOUSINGS, SLEEVE I.D. IS 2.170"

 

List Price $24.44

 

Your Price $18.80

 

In the thread, Trouble advised someone had bought all 100 they had made and he was trying to get in touch with him. He also posted a link to Held Motorsports for 2.170 parts.

 

COK12462

COIL OVER NUT FOR 2 1/2" I.D. SPRING, FITS COK12442/48/49 COIL OVER KITS AND COK12453/59 COIL OVER SLEEVES

 

List Price $16.73

 

Your Price $12.87

 

COK12470

COIL OVER TOP, NON-SLOTTED FOR 2 1/2" I.D. SPRING, FITS PRO SHOCKS and MOST STRUT APPLICATIONS

 

List Price $16.30

 

Your Price $12.54

 

 

Summit seems to have the best deal for 2.5" springs as listed on Brian's page.

 

I'm planning on running 10" springs front & rear, no desire to radically lower the car beyond stock ride height (my problem is I curently have 6" between the 14" tire & fender lip, no idea what the rate is for these springs but it must be up there or from another car).

 

EDIT

I took the struts apart & the springs that were in there are 15" uncompressed.

[Twoeightnine]

Howdy

After researching a bit it seems that if one cops all the parts from the various sources listed in the forum, minus taking a chance on E-Bay discount springs, the price savings is not a great deal verses purchasing a complete kit from Modern Motorsports or Ground Controul. Since I was buying other stuff as well I went ahead and bought a complete MMS coil over set.

As for the installation, it took me so long to decide that my window to install them has passed for the moment. I will be waiting untill the car returns from paint to do the mod. It may be best for me any how as I can put the suspension bushing kit in on reassembly and basicly have the suspension out only one time. Not to mention the overspray concerns that I had concerning the install.

As for the install situation, look above at jmortensen's suggestions. And coupled with one that I saw that 440Man started that mentioned "mock up". In otherwords dont commit to the collar placement if one has concerns. Hose clamp (maybe two) lower it to the ground and check.

Sounds fair to me!

I'll still take pic's but it will have to wait un till I get er back.

 

Let me know!