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The Strut thread - Koni / Illumina / Tokico / Carrera / Bilstein / Ground Control


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An interesting thing about the 3000gt bilstein inserts. They use the threaded rod and nut on the bottom of the strut to carry all of the rebound loads that the strut experiences. This is good news for the front insert, as the gland nut becomes non critical in terms of carrying loads. Its primary purpose then turns into a contaminant shield. I'm not sure what to do in the rear where you can't run the insert all the way to the bottom of the strut tube. Maybe lower the rear strut towers??

 

R36-5022-H0.jpg

 

Also, its standard practice for 3000gt owners to trim 1" to 1.5" off the internal bump stop. So that gets you upto 5"-5.5" of total travel.

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I'm not sure what to do in the rear where you can't run the insert all the way to the bottom of the strut tube. Maybe lower the rear strut towers??

 

Bore out the bottom of the strut tube and weld in an upsidedown cup that's the proper length of the spacer and has a mounting hole in the center.

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I'm not understanding the advantage to attaching the strut at the bottom vs with a gland nut. If you use a spacer made from a piece of tubing, and you'll need to have a spacer anyway because of the short body length, the post on the bottom won't hit anything. I don't see the advantage to having the strut screwed in at the bottom, so why bother with all the rest of it? What am I missing here?

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I feel from a simplicity standpoint it would be nice not to have to deal with the gland nut for load barring. Getting the spacers just right, keeping it tight, ect ect ect.

 

It looks like if I section the struts down 4.25" front and rear, I'd end up with a weld in spacer that is ~3.25" tall in the rear. It is designed as a 1.75" X 0.12 tube with a 10ga washer welded to the top of it. I'd then weld it into the bottom of the strut tube. The struts are fully compressed in these renderings.

 

modtubeassy.jpg

 

modtubeassy2.jpg

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Be very, very careful about shortening the strut too much. Lots of 280Z guys found out the hard way what happens when a 240Z strut is put in the back of their car.

 

No shorten then 15" in the rear and 13.25" in the front (measured inside the strut tube) for a 240Z.

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Do you guys run spacers under the P30-0032 insert in the front? From what I can tell, its not how much I I section the strut housing, but the total distance from the bottom of the strut tube, upto my camber plate that will set my spindle height. If you compare the R36-5022 to the P30-0032, there extended length is 18.89" vs 19.74". The middle of each inserts travel is 16.93" vs 16.75". If you remove 1.5" from the R36-5022 bump stop, these numbers become 16.18" vs 16.75". In this case, at static ride height, with the insert in the middle of its travel, the R36-5022 insert will lower your ride height 0.57".

 

Are the factory upper isolators the same thickness front and rear? I will be running TTT camber plates, so I have to take that into account as well.

 

As far as gland nuts go, they do work. They would just add $50 a corner to buy them as I'd need a female and male gland nut per strut. I may go that route if I can't get the strut in the correct part of its travel at my desired ride height.

 

Justin

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I made spacers for my P30-0032 struts, but that's because they were previously sectioned to fit Tokicos and I didn't want to do the work over again. I think you could probably run the front sectioned to fit the P30-0032s, but definitely not the rears.

 

If you were planning on running with no gland nuts at all, I'd suggest you rethink that idea. That bottom post is not going to deal well with the amount of side load you'd put on it without a gland nut functioning to hold the insert.

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I did tokicos on a friends 280. The insulators in the rear are much longer than a 240. In the front the insert touched the bottom no spacer, in the rear we had to cut and shorten the rear just a little and add a big spacer. this was because he was running camber plates of the same thickness front and rear. If we would have cut the rear struts short with no spacers the car would have had no droop travel in the rear. Now the Bilsteins are even shorter, so you may not even have to section the rear at all if you use thin camber plates. FYI I used no spacers on the front and long spacers on the rear for my 240 with the bilsteins

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I made spacers for my P30-0032 struts, but that's because they were previously sectioned to fit Tokicos and I didn't want to do the work over again. I think you could probably run the front sectioned to fit the P30-0032s, but definitely not the rears.

 

If you were planning on running with no gland nuts at all, I'd suggest you rethink that idea. That bottom post is not going to deal well with the amount of side load you'd put on it without a gland nut functioning to hold the insert.

 

The Z cars are pretty much the only car I've ever seen that uses gland nuts for strut inserts. Every other MacStrut car uses a bolt that goes through the bottom of the strut housing and up into the insert. The only Koni insert that does not come with a threaded boss on the bottom for a bolt is the 8610/8611 series. I have Koni 4th Gen Maxima front inserts that I'm thinking about using in the rear of my Z - they are a good 3" taller than the 8611's but I already have them so it wouldn't cost me anything to put them in.

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It doesn't make any sense at all to have a stud at the bottom of the strut insert take all the load from an engineering perspective. I've never seen and I would laugh my ass off if I did see someone design a strut that bolted straight through the bottom with no bushings or anything because that would be a threaded section SEVERELY loaded in bending. I suspect that the stud may be a way of attaching the bottom of the strut to the housing that some manufacturers feel is more secure and maybe it centers the insert in the housing or something like that, but there is NO WAY that manufacturers are relying on just a stud in the bottom to deal with all the side loading going into the insert. It makes NO SENSE to do it that way and it would be REALLY weak.

 

Since it is the 3000GT that we're talking about here, I looked this up: http://www.stealth316.com/2-shockremoval.htm

 

You can see that the strut housing bolts to the spindle in double shear through two mount holes spaced out from the bottom, just like on a Porsche, Mustang, etc. I haven't changed struts on too many different types of cars, but they either had gland nuts (Z, 510, etc), or they had a strut that bolted to the spindle and were not an insert like the 3000GT parts. You can see that there is in fact a gland nut on the Mitsu strut housing, but it appears to be crimped on not screwed on.

 

I would assume that the insert that Justin is looking at can be changed out on a part like is shown here:

 

http://www.streetperformance.com/part/bilstein/strut/1079195-f4-r36-5022-h0.html

 

http://www.allshocks.com/productimages/R36-5022-H0.jpg

 

Actually, I just noticed when cutting and pasting the image location that the part number for the above and the part number for Justin's insert match. Coincidence??? I think that insert does fit the housing above. See the gland nuts in the picture? They're there for a reason...

 

That strut insert (and more specifically that stud on the bottom) is not the part that takes the side loading through the suspension. It screws into a sturdier housing which takes the load, and uses the stud on the bottom and a gland nut on the top (so as not to isolate the insert from the strut housing) to do so. The most I think you could say is that by virtue of being attached to the strut housing the insert shares the load, but it's clear to me that the housing is what is doing the work, and the strut insert is there to damp the oscillations of the spring, not to absorb the side loads in the suspension system.

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The gland nut that I will be using is a press fit on the strut tube. On the bilstein install for the 3000gt, you cut the top of the strut tube off (including the threads for the gland nut). You then use the bilstein press fit gland nut and the bolt on the bottom. They work together to secure the insert in the strut tube.

 

Here is a install pictorial:

 

http://www.cardomain.com/ride/348632/3T

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I wonder if this will work without further mods for those of us who have welded the female carrier onto the housing to fit the P30 damper? It would seem to be the case given this

 

The M52 X 1.5p gland nut part number is B4-B36-U242-B2

 

And the fact that the female carrier whose PN is lost somwhere in the preceeding 18 pages I think is M52x1.5 as well?

 

Obviously a little more reaming out the inside of the carrier like this would be required:

http://album.hybridz.org/data/500/medium/step14-file-out-carrier.jpg

http://album.hybridz.org/data/500/medium/step14-damper-through-carrier.jpg

 

Thoughts?

 

Dave

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Every other MacStrut car uses a bolt that goes through the bottom of the strut housing and up into the insert.

 

These are some cars that I know use gland nuts:

 

Toyota AE86 Corolla

Toyota MR2

Nissan Sentra/240SX

BMW 320is

Scion Xd

Most Rabbits, Golfs, Scirrocos, Polos, etc.

 

Gland nuts are common on Mac and Chapman strut cars.

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These are some cars that I know use gland nuts:

 

Toyota AE86 Corolla

Toyota MR2

Nissan Sentra/240SX

BMW 320is

Scion Xd

Most Rabbits, Golfs, Scirrocos, Polos, etc.

 

Gland nuts are common on Mac and Chapman strut cars.

 

The Sentra most definitely does not use gland nuts.

 

2580396695_3ce8d7f50b.jpg?v=0

 

2580394883_a3a0dab048.jpg?v=0

 

2574693355_d46c4d3ddf.jpg?v=0

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The Sentra most definitely does not use gland nuts.

 

2580396695_3ce8d7f50b.jpg?v=0

 

2580394883_a3a0dab048.jpg?v=0

 

2574693355_d46c4d3ddf.jpg?v=0

You are right, there is no gland nut there, but you missed the point of the gland nut completely. The strut insert on the Sentra is captured in the stronger housing by the bolt on bottom and the lip on the top which functions just like a gland nut. Regardless of whether the nut is on top or a bolt on the bottom or what, the bolt on the bottom doesn't take the side loading from the strut (although it does take rebound forces). The housing it is inserted into takes the big loads. So when you step on the brakes, that stud at the bottom isn't getting worked. The housing that it installs into is doing the work, because that strut insert is firmly held in the housing at both ends.

 

In Z terms, the strut insert that Justin is looking at doesn't have a lip on the top so that it can be held tightly in the housing without a gland nut. The Z absolutely needs one. Without it the strut insert would wobble in the housing, and the side loads WOULD transfer to the stud at the bottom, and this would be bad, not to mention it would clunk like hell as you drove around. The Z struts are firmly held at both ends too. The gland nut holds the top, and compression against the bottom of the strut tube holds the bottom.

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Jon, we are talking about 0.020" clearance per side on these. I'd be surprised if these inserts slip right into the strut tube really. IDK if they are going to "clunk" around. I do plan on using the press fit gland nut provided. I'll have more measurements and pictures when these arrive.

 

Justin

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Jon, we are talking about 0.020" clearance per side on these. I'd be surprised if these inserts slip right into the strut tube really. IDK if they are going to "clunk" around. I do plan on using the press fit gland nut provided. I'll have more measurements and pictures when these arrive.

I'd bet money on it. I've had monoballs with less slop than that that were very easy to hear clunking. If you're using the gland nuts it's a non-issue.

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