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Coilover Question. How much to section & replacement for strut top bearing


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#1 MaygZ

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Posted 14 November 2012 - 09:56 AM


Before I start cutting struts; the bodies of the Z31 inserts are 363mm; the old fronts are 387mm and the old rears are 420mm.

My maths says fronts are 24mm longer and the rears are 57mm longer.  My question - does that directly translate as sectioning 24mm out of the front struts and 57mm out of the rears?  Will this make the rears too short?  I don't have a weighted car (ie a full car) to lower onto them to measure.

I was looking at putting the sleeves on 100mm from the ORIGINAL height top of the struts.  Is this what has worked with others?

Thanks guys

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#2 Lurch ™

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Posted 14 November 2012 - 04:37 PM

Before I start cutting struts; the bodies of the Z31 inserts are 363mm; the old fronts are 387mm and the old rears are 420mm.

My maths says fronts are 24mm longer and the rears are 57mm longer.  My question - does that directly translate as sectioning 24mm out of the front struts and 57mm out of the rears?  Will this make the rears too short?  I don't have a weighted car (ie a full car) to lower onto them to measure.

Take 24mm out of the fronts & 24mm out of the rears.
If you take 57mm out of the rears, you'll end up with the arse of your Zed dragging on the ground - i.e. the ratio is not equal front to back.
Don't forget to take into account the thickness of your cuts in the overall measurements.
You'll need to pack the bottom of the rear inserts up inside the tube as well, (use an appropriate length packer) to make the insert sit hard against the gland nut.

I was looking at putting the sleeves on 100mm from the ORIGINAL height top of the struts.  Is this what has worked with others?

Thanks guys

75mm for the front - 50mm to 75mm for the rear.
4 welds equally spaced apart top & bottom, 10-15mm long each.
DON'T fully weld them on...

#3 MaygZ

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Posted 14 November 2012 - 05:04 PM

75mm for the front - 50mm to 75mm for the rear.
4 welds equally spaced apart top & bottom, 10-15mm long each.
DON'T fully weld them on...


Thanks Lurchos.  I'm thinking of coming for a drive for the sleeve welds - you've seen my welding and it aint getting much better  :'(


I've sectioined the fronts and I'm a little surprised at how easy they were - when you take your time.

#4 nat0_240_chevZ

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Posted 16 November 2012 - 05:21 PM

leave them full height, and dont worry about that loss in bump height, as if you are running much stiffer springs i doubt youll need the bump stob at all.
use thos shock spacer rings ive shown in another thread, these pack up the cland nuts and also centr the strut cartride at the bottom if using 260z struts.
Only reason sectioning has come about is because not many people can have the gland nut thread machined easilly into the top of the strut housing/tube,
so cutting and welding appears to be the easiest option???? apearantly....
I did not section, cut or weld a thing, and im using the same inserts, gland nuts & strut tubes/housings, only some carefully measured packers/spacers which make this whole assy so, so easy.
You WILL get a few die hard peeps that say you need every once or inch of suspension travel, but this is crap,
what your allowing your car to do is actually bottom out the tyre on something it was not designed to touch, ie inner guard, outer guard or other,
the small (Very small) loss in travel does not effect handling, and unless your hitting spoon drains and speed humps at a million miles an hour, or plan to drive your Z off of platforms and gutters 1 foot high, DO NOT WORRY ABOUT IT.
My expert opinion, others feel happy to flame,
but lets just say, I think my designs and mods through completely before watching/following the americans, redneck version...
not meaning to be sinicle, but its the only way sometimes.
What you dont want to do is pack the insert/shock up, just pack above it so the gland nut holds it down, as you are trying to retain the same amount of 'drop/droop/max extension' without compromising where the stoke of the shock is attained, ie not at the bottom or top of the shockes range.
any q's please search for an old thread of mine.......
nat0

#5 Zedman240®

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Posted 16 November 2012 - 07:23 PM

I thought bottoming out was near impossible until I found out otherwise.... easy way to check is grab a cable tie and wrap it around the shock shaft. Slide it all the way down till it meets the shock at the bottom then go for a run. Mine ended up in the bump stop on just a small drive around and mind you I had 300lb springs and that wasn't even on the track. If you do have Koni's fitted, once they have been bottomed out without a stop, a full rebuild will be needed of the shock. Best insurance is a small lump of urethane that will save you many hours of labour and a few hundred dollars.

#6 Riceburner

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Posted 16 November 2012 - 07:44 PM

What you dont want to do is pack the insert/shock up, just pack above it so the gland nut holds it down, as you are trying to retain the same amount of 'drop/droop/max extension' without compromising where the stoke of the shock is attained, ie not at the bottom or top of the shockes range.
any q's please search for an old thread of mine.......
nat0


+1 Well said Nat0. Also, If you pack below with lowered springs you won't have any spring retention at full drop allowing them to move on'off the perch. Definately pack ABOVE and use new bump stops, you'll still hit them.

#7 luvemfast

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Posted 16 November 2012 - 08:10 PM

Different series. But mechanical principles are the same.
I have spacers on the top of mine and bump stops on the rods.

#8 nat0_240_chevZ

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Posted 19 November 2012 - 04:56 PM

I thought bottoming out was near impossible until I found out otherwise.... easy way to check is grab a cable tie and wrap it around the shock shaft. Slide it all the way down till it meets the shock at the bottom then go for a run. Mine ended up in the bump stop on just a small drive around and mind you I had 300lb springs and that wasn't even on the track. If you do have Koni's fitted, once they have been bottomed out without a stop, a full rebuild will be needed of the shock. Best insurance is a small lump of urethane that will save you many hours of labour and a few hundred dollars.


Dimitri, cause you will be effectively pack above the shock, the gland nut is effectively a mech stop to limit any way of bottoming out the shocker, this is why I wentdown this route, as the shocker is working in its ideal range, and now way possible of bottoming out the shocker, I did not use any urethane or stop whatsoever, although i am thinking about putting a rubber/urethane disc just 5-10mm thick. but id prefer to bottom out the gland nut to the upper perch than the shock itself.
Nat0

#9 MaygZ

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Posted 27 November 2012 - 04:40 PM

OK.  I've got another coilover question.  Please don't roll your eyes.

Focusing on the fronts:- I've trimmed down the rubber and steel hat tops and they've come up well.  I need to open the centre hole of the hat to accept the larger Koni insert shaft - Lurchos has guided me on that one.

There is a bearing in this hat that allows the strut to turn - for steering.  My bearings are not very well so have looked for new ones.  They are no longer made but japan has some.  6 weeks and a bit over $90.  Then add the $100+ for the camber kits on the lower arm to allow some adjustment.  This got my thinking about weld in camber plates  ;D

My question - for anyone who has fitted or held these items - how do they allow for the need to turn the struts?  The need to steer?  Is the whole strut only supported in the rose joint in the camber plate?  How does the coil-over top plate hold pressure on the spring.  It seems to me that that plate needs to pressed hard against something solid.  Do these plates have a bearing similar to standard to allow for steering?

The Z Store ones  http://www.thezstore...PSDC15/23-4188  seem to have some roller bearings to deal with a need to change direction.

I can't see how the AZC or the K-Mac ones deal with it.

#10 luvemfast

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Posted 27 November 2012 - 09:13 PM

Basically. Between the top spring perch and the camber plate is a thrust bearing.
I'd put a pic up, but I'm not by the computer.
I'd walk to the study. But I'm dizzy from rolling my eyes.  :P

#11 RB30X

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Posted 28 November 2012 - 09:33 AM

T110 is the part number for the strut top bearing. From my thread: http://www.viczcar.c...c,6875.135.html
Make them search the part number rather than search your model etc.

#12 MaygZ

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Posted 30 November 2012 - 06:30 PM

T110 is the part number for the strut top bearing. From my thread: http://www.viczcar.c...c,6875.135.html
Make them search the part number rather than search your model etc.


You are a bloody legend!!!!!  $20 each and in stock!!  The bloke at the bearing shop was a bit red faced that I was able to tell him a different one.

Thank you very much.

#13 RB30X

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Posted 30 November 2012 - 06:39 PM

My pleasure mate.

I spent an hour going through books and measuring bearings at my shop before we found that.




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