threaded tube placement

[Guest Mr. Big Business]

OK, I searched through the archives and couldn't find an answer to this. How far down the strut tube should I place the threaded tube for my coilovers? They are 10 inch springs, 200 lb in the rear, 175 in the front. I sectioned about 2 inches out of the rear strut. The threaded tube (this is a GC setup) is 6" long. I thought about just placing it so the uncompressed spring is in at the bottom of the threaded tube, but I can't even lift the tube that high on the strut tube without it hitting the gland nut. help!

 

 

This is what it looks like right now. I put the threaded sleeve about where I've seen it on some other websites. Is this what it's supposed to look like?

 

If anybody has done this before and has the numbers handy, could you tell me which illumina (adjustable) strut insert is the rear, and which is the front?

 

Thanks,

Henry

[blueovalz]

Mine are 4.24" from the bottom of the threaded tube, to the top of the cast steel boss that holds the strut tube, on the FRONT. On the REAR, this same measurement is 5.5" (all tubes had about 2" removed from them). Now with that said, I am using 200 f/r, and at the above spacing, I am currently riding on the bottom most threads of the threaded tube (my car sits LOW). But, this set-up was designed for no rubber spacer at the top, as your picture does have them. My car only weighed about 2160 in race trim. The ratio of sprung/unsprung weight on these cars is not real good. With 200lb springs, I only had about 1.9" of compression on the springs (avg). Your car will probably be heavier. Just to get you in the ballpark, I'd assume a 2.5" compression with the 200 pounders and 3" with the 175's (I'm assuming your car will weigh several hundred pounds more than mine). Then find out the mid point of the strut movement range (if strut movement is 6", then midpoint is 3"). Now measure down the fully extended strut from the bottom of the upper spring locator, down 7.5" (front, and 7" rear)+ 1/2 the amount of strut movement (assuming 3" in the example above) possible + 1/2 of the length of the threaded tube. This will be where the bottom of the tube should be located. At this point, the suspension will be setting midpoint on the threaded tube, and midpoint in the strut movement range. Things that will change this, is weight of the car (mine is a stripped bare 71 240), and your intended ride height. Somebody double check my post here to make sure I did not leave anything out.

[Guest Anonymous]

Are we talkibng "280" Zee here???? Get your strut cartridges first to check fit before you do any more welding since the "fronts" will come with little room for mistakes. The "rears" will need a spacer placed at the bottom of the tube to get the z front cartridge to fit snug against the gland nut.I have worked on two sets of 10 inch coilovers on 280 Zees and took a one inch cut on either side of the the original spring perch welding bead, which would place the new joined strut tube bead in the same place as the original weld bead for the a two inch section.(this gives the car about a 4 inch drop with 5 inches to adjust up on the sleeve) A five inch adjusting sleeve will come out flush to the bottom of the gland nut on a two inch section of one inch on each side of the original weld bead on the "front strut tubes".. You will want your new spring perch washer just above the welded joined halves to weld all together for more strength. You may have to go to a shorter adjusting sleeve due to your "cut section" placement.The rear struts will require a spacer placed in the bottom of about 1 3/8 to take a front strut cartridge from the Zee . You will use an 80's VW GTI front strut cartridge for your front struts. Since these are GROUND CONTROL , did you get them from RossC. ?PS the new spring perch should come out at nine inches above the cast part of the rear strut tube.The rear coilovers will need a spring compresser to assemble while the fronts will not on my method on a two inch section on a 280 Z.

[Guest Anonymous]

Re read my long post since I have edited it twice.

[Guest Mr. Big Business]

Let me clarify a couple things here. This is for a '71. I already have the struts, which I ordered directly from Ground Control, along with the springs, threaded sleeves, etc. The reason I asked about the part numbers is because I wanted to make sure I didn't have the fronts and rears mixed up. The rear strut inserts are longer, right?

TZ, are you saying that you chopped 2 seperate one inch sections out of your strut tubes, just so you could use the factory weld bead to support your threaded sleeve? That seems like a lot of extra work.

Why would you need a spacer for the rear strut insert? According the the instructions included with the GC stuff, one just measures how much one needs to cut out of the strut to make the insert fit, then cut that much out and weld it back together. That's what those two pieces of tape are for on the shaft of the strut insert in my picture above - to accurately measure how much shorter the strut needed to be. If that's wrong, then Ground Control can look forward to an angry phone call on Tuesday morning.

 

Thanks again,

Henry

[Guest Anonymous]

The struts are longer for the rear. I did not cut two sections out but cut the original weld bead out by cutting one inch below and one inch above the original weld bead discarding the two inch section with the original weld bead in the center (of the 2 inch discarded section). You are working on 240 tubes and the 280 tubes are bigger. I would not section no more than 2 inches.You want your 2 inch section cut directly below your new spring perch (large washer)and where your threaded adjustment sleeve comes directly under your fully threaded in gland nut. Trial fit your strut cartridge into the unwelded strut tube pieces and estimate if you have a tight secure fit for the gland nut to hold the cartridge firmly in the tube. now see if the 6 inch sleeve will fit where your new perch will be and under the gland nut.You can always weld the tube pieces together and smooth down the weld to get the sleeve over the weld to lower the adjusting sleeve further down but I am not that good of a welder to make that strong of a weld to grind the bead off to fit a sleeve over the weld. You can go for 4 or 5 inch adjusting sleeves if the six (6) inch is too long for your cut location..I could never make heads or tales out of the G Control website so I skipped them as a source. Let me point out, (Excuse me but) we have two excellant vendors/members: SCCA (Mike) and Ross C that sell quality coilovers and probably lower than Ground Control who will walk you thru the conversion and Like Dan Juday sez: "treat you like a brother" Ross C sells the ground control adjusting nut which is about the best.If my directions are not clear shoot back. and my little lecture is for every one's information "Patronize our guys" PS>>> I have studied your picture enough to see your spring is upside down (Hehe) and it appears your gland nut is tightend down. Is the strut cartridge in there good and Tight? If so just move your sleeve and spring perch up to the gland nut and tack weld ever so gently to hold in place for a trial fit.You should have some o rings to secure the sleeve to the strut tube for adjustment purposes You have six inches to go nowhere but up which should put you about any level you want.

[Guest Mr. Big Business]

TZ, BlueOval,

Thanks for the advice. It looks like by using BlueOvals calculations, my threaded sleeve will end up pretty much where TZ advised to put it.

TZ, I'm running a TIG setup so I can get pretty decent looking welds. I actually ended up with no weld bead on the outside of the strut tube, but I did get so much penetration that I had to grind off some weld from the inside of the tube (that was no fun, 7 inches down the tube) On the next 3, I will probably do my cutting and welding closer to the top, so that the cut and welded area will be under the threaded sleeve. That way the unmolested factory section of the tube will be supporting the weight.

I wondered if anyone would point out my upside-down spring. I did get the little o-ring with my tubes, so I'll make sure to slip it on there first.

 

Thanks again,

Henry

[blueovalz]

I'd like to add one more comment about my approach to where the section should be removed from the OEM strut tube (when shortening the tubes). My approach or thoughts on this is that the section should be as high up on tube as possible, or at least above the new spring perch location. This is because the weight of the car then rides on a spring that sits pretty much on unmodified strut tubes. With the weld under the tube, then the weight of the car rests on what is hopefully a competent welding job.

[Guest Anonymous]

Why did you have to section your strut housings if you're using 10" springs? The rear threaded perch should be about 7.5" from where the strut tube enters the casting. The front about 5.375" is where the brake line hose attachment is.

 

Hope it works out for you.

 

Jon

[Guest Anonymous]

Henry..... Blue Oval is right about running the cut high up for strength. TIG welding is great for struts.The strut thickness is ideal for hot MIG welding without blowing through. I wove my MIG weld from the the joined strut bead to the metal washer spring perch which really reinforced the joined strut tube sections to the new perch.. My reason for the 2 inch section is to severally lower the "Fatboy" Tomahawk Z "three" inches to look right. Nezzie 76 has a Vello Rossa and also needs a severe drop because both of our cars are over 300 #s lighter than stock 280 Z's. If you are going to have adjustable coilovers you might as well have a full adjustment of 4 inches or better since the sectioning is not supposed to limit the strut travel that much from stock.