Don't overlook that application specific gland nuts are supplied with the replacement shocks, of all brands.  The original Nissan gland nuts were meant to thread all the way down in to the strut tube and seal against the tube and the shaft to keep the oil in.  The replacement gland nuts are meant to center and clamp the new self-contained shock in to the strut tube.  The strut tubes themselves were not manufactured to accept a shock seating against the bottom where the welds are.  In a way it's just blind luck that so many of them have fit well.  Not a surprise that some finessing is needed in certain cases.

I used the gland nuts supplied by Koni.

madkaw has posted about having to grind the welds at the bottom of the strut tube.  I think it's in this thread, way back.

Here's his story.  It starts at post #188 on page 8 if you can't find the right thing to click on.

 

It's a different problem.

I have the same issue like av8ferg described here:
https://www.classiczcars.com/forums/topic/61542-koni-sports-for-classic-zs/?page=12#comment-628560

https://www.classiczcars.com/forums/topic/61542-koni-sports-for-classic-zs/?page=12#comment-628872

I am already in contact with MSA - I will disassemble everything tomorrow and get measurements so that we can find out if either the thread on the strut or the gland nut are out of spec.

Just FYI.
I had two wrong gland nuts in the package. M52 was required, but they were only M51. Without the damper centering the gland nut, it was a very loose fit and the nut popped out at around 50Nm.
The outer diameter of the gland nuts should be around 51.80mm to work correctly.
 

You're saying that the problem is fixed now?  Did you order the wrong product or did the wrong nuts get put in your package?

There were the wrong nuts in the package.

As there hasn't been a new post on Koni struts for some time, I'm hoping to get help. As is, I'm attempting to install new Koni struts (model; 23-1031 KONI Struts) on my Series I. The struts were back ordered and arrived in July. Fast forward, the new struts (yellow) are a little too long to fit as they should. I have spoken with 'Dave' at 'Motorsport Auto - The Z Store' the supplier, and he assured me that they sent the correct struts. Anyone else in this situation? Just wondering if the bolt at the bottom of the housing could be safely ground down without creating potential damage. Suggestions are welcomed...Thanks  

Yep, I went through that issue on an early Z.. see above.. 

after carefully grounding down the bottom nub on the struts.. they worked for me! 

This is not a new problem, any number of owners of early cars experienced the same issue, myself included. The problems lies with a thick weld bead at the bottom of the strut tube that prevents the KONI insert from fully seating. The problem is visible when the gland nut will not install to the correct depth. KONI and MSA worked on a solution in the form of revised gland nuts with a longer thread body. MSA supplied these modified gland nuts at no cost to customers reporting the problem. I recommend you reconnect with MSA and request the modified gland nuts. BTW, the problem seemed to be limited to the front struts as there were no reports of rear struts having the issue.

Edited October 12, 2024Oct 12 by jfa.series1

2 hours ago, Dr. 240Z said:

As there hasn't been a new post on Koni struts for some time, I'm hoping to get help. As is, I'm attempting to install new Koni struts (model; 23-1031 KONI Struts) on my Series I. The struts were back ordered and arrived in July. Fast forward, the new struts (yellow) are a little too long to fit as they should. I have spoken with 'Dave' at 'Motorsport Auto - The Z Store' the supplier, and he assured me that they sent the correct struts. Anyone else in this situation? Just wondering if the bolt at the bottom of the housing could be safely ground down without creating potential damage. Suggestions are welcomed...Thanks  

There's a discussion back around page 17 and earlier about the weld bead and the modified nut.  Suppsoedly there was a note on the MSA pages about it but I don't see it.  You might contact Jospeh or Koni Lee since they were in the conversation.

@Joseph@TheZStore

@KONI Lee

https://www.thezstore.com/product/4296/koni-sport-adjustable-gas-strut-rear-70-8-74-240z-260z-coupe