Joseph@TheZStore

KONI Sports for Classic Z's

Recommended Posts

5 hours ago, grannyknot said:

ZH, have you never had to pull a shock out of a strut tube that is rust welded in?  The oil may not be needed for the operation of the shock but it certainly is needed for our strut tubes.

@DangerBoy703, take mercy on the next guy who replaces those shocks, put some oil. 

If you assume that that is the purpose then you need to be sure it's filled to the top.  If it's halfway, you''ll still rust-bind the top of the tube.  Maybe KYB uses better paint that doesn't break down and let the shock body rust.  Are the people at KYB ignorant?  A thin coat of anti-seize might serve the same purpose.

The instructions should be more thorough.  Let's see what KONI has to say.  @KONI Lee  What is the purpose of the "fluid"?  What is the best fluid for the purpose?

  • Like 1

Share this post


Link to post
Share on other sites

On 4/19/2019 at 10:49 PM, Joseph@TheZStore said:

Actually gentlemen those numbers are correct. The KYB's have always been about 10mm shorter. The Koni's are actually the proper length. This is based on a cartridge Koni has used for 50 years.

We know of numerous installs already on 240Z fronts that have lined up correctly. Our test pilot Hector has the same strut housing numbers you mentioned on his 240Z and they installed correctly.

Even though it sounds as if you have the proper height struts in the front (based on the comparison to the KYB's), please confirm for us the numbers on the Koni cartridges you just received, as well as that measurement of the strut cartridge body. Please also include if you can read them any numbers on the KYB's, .

Greg has been dismantling 240Z's since the early 80's, and he added that in addition to the often occurrence of somebody putting a spacer at the bottom, that also he has seen numerous times where oil and dirt in the housing have combined over the years to literally make its own 'spacer' of sorts. He said he has had to at times in the past literally dig years of near solid junk out the bottom of the strut housing.

The only other possibility (assuming the numbers and height check out after you send that to us) would be strut housing modification, which sounds unlikely in your case, but just to be certain, if you can measure the height of the strut housing as well (outside), we'll confirm that too.

Sorry you're having an issue, we'll get it figured out!

 

Thanks for the replies gentlemen! For clarity, I've collected all info on my setup in this post.

Car: 05/71 HLS30-30267 US model. Two previous owners before me (1971-1979 / 1979-2013). To my knowledge, it's an unmodified/stock car. It came with original open-type struts, springs and strut housings. The struts were leaking so I replaced them with KYB Excel-G's and supplied gland nuts.

Strut housing part numbers: 54303-E4151 and 54302-E4151. I can't find any production date/number stamped on them.

Strut housing dimensions: Inside: Between 15" 1/16 and 15" 1/8. Outside: 16" (slightly difficult to measure precisely atm as they're assembled). It's difficult to see the inside bottom of the housing, but I did take a photo and it looks fairly clean. Can't see any sign of inside spacers being used.

Koni front shock part numbers: 8641 1031SPORT (1-2019)

Gland nut: I first tried with the supplied Koni nuts. I also tried with the original nuts and the two variants of KYB nuts (front / rear). As someone mentioned, the front KYB struts are shorter and therefore user a spacer inside the gland nut.

Strut lengths: The (yellow) housing part of the Konis are 387mm (15 1/4"). The KYBs are 377mm (14,84"). It's also worth noting that the two brands of struts have different bottom shapes - the Koni is convex while the KYB has a concave "cup" welded to the bottom. Depending on the shape of the bottom of the strut housing, ths might affect the fit.

Gap: I curently have a gap of around 8mm between the rim of the gland nut and the top of the strut housing. According to the Koni supplied instructions it should be between 1-4mm. On one side, the threads won't catch at all. On the other side, the threads enter but I only have a quarter turn before it's full stop.

 

Measured distance.jpg

Share this post


Link to post
Share on other sites

Look for witness marks on the paint at the bottom of the cartridge.  You should be able to tell if it's the edges like gundee shows or something else.

Share this post


Link to post
Share on other sites

I tried Gundee’s technique and the gap is now 6mm (should be between 1 and 4). Not sure if it’s sufficient, but I don’t dare to remove more material.

I managed to take a better photo of the bottom of the housing. Is that a spacer in there or does the bottom look like that?

If there is a spacer, how do I remove it? Is it possible to knock it out from the bottom side, or is the bottom «cap» welded in?

 

08A494AD-D052-4757-9846-2F58B037A2B3.jpeg

Share this post


Link to post
Share on other sites

I dont remember a step in the bottom of the strut tube

Share this post


Link to post
Share on other sites

On closer inspection the step seems to be the actual bottom «cap». It is shaped like this, and welded to the bottom.

 

So now the Konis are in. I managed to reduce the gap to 5,3mm, by tapering the bottom cap and the top ring of the Koni, as well as the inside of the gland nut.

My gland nut looked like in (A). I tapered them by hand like in (B). If I had access to a lathe I would shape them like in (C). This alone would have done the trick, no modification of the strut itself would have been necessary.

 

28AB91AD-BA40-47B1-8FDC-DD65D1F564FD.jpeg

Share this post


Link to post
Share on other sites

Hello All, sorry for the late response.  I was away from the internet and emails for most of three day Easter holiday with family so I am just getting caught up to a flurry of activity here.  Issues of the last few days:

 

  1. Oil in the strut housing around the insert is always a good idea but it does not really matter what type oil it is.  The benefits are twofold, although one is real world and the other a bit more theoretical. As mentioned in posts above, some type of oil between the raw steel inside of the strut tube and the outside of the insert can reduce or eliminate the chance of rust forming between the two and making it very difficult to remove the strut insert from the housing many years down the road if any service or replacement is ever needed.  Any kind of spare oil will do just fine so leftover used engine oil, any gear or motor oil left at the bottom of an open bottle, etc. will do just fine.  Anything to fill the void so that water or moist air cannot accumulate and start to rust the internal surfaces.  I do not recommend anti-freeze as it is water based and will very likely start to rust and make insert removal much more difficult.  The more theoretical benefit is potentially improved from inside to outside heat transfer but honestly unless you are trying to race off-road with extreme sustained piston speeds and heat generation, there is no need for cooling the insert for its own function.  When we had the KONI Challenge road racing series, we found that there was more wheel well heat generated from the brakes and hubs that might spread into the strut than there was heat inside the strut that needed to dissipate out.

  2. Regarding the fitment concern on Nils’ front struts, I think there may be an internal lip or edge that it is catching on and not letting it drop all the way to the bottom. These inserts are exact dimensional matches to the earliest KONI 86 series red strut inserts that were offered from the beginning.  I checked old ‘70s KONI catalogs that simply state “1970-1974”so there was no exclusion for super early production strut housings or a later start-up date.  I think Nils’ situation is an anomaly and exception and not the rule so they can get a deeper look on a case by case basis.  If someone does have an issue, please let Joseph or KONI know.

  • Thanks 1

Share this post


Link to post
Share on other sites

Thanks for the clear reply KONI Lee.  You covered all of the bases.

Since the factory struts were designed to be sealed and full of fluid, maybe, for the guys that like to go the extra step, cleaning, priming and painting the inside of the tube would be worthwhile when converting to replaceable cartridges.  Rustproofing via coating, instead of oil.

Oil is kind of messy and can slosh up and cause a grimy strut tube top.  Sometimes people think that their strut is blown when it's just had a cartridge swapped for the old internals.  Just adding a little more to think about.  The old Nissan fishy-smelling oil is what typically ends up back in there.

Share this post


Link to post
Share on other sites

can i trouble anyone to tell me if i have this done correctly. i followed the directions as best as i could make them out. i was unable to finish because i needed a spring compressor for the Eibach's so i figured i would double check. gland nut gap is 3.3mm

strut.jpg

Share this post


Link to post
Share on other sites

i dont know what its purpose is. it was in the package with the gland nut and other small parts. that placement is what i took the instructions to say.

Share this post


Link to post
Share on other sites

i had googled lots before attempting the install but didnt find any Z specific links other than this thread and i do not know enough to know what info i can take from other applications

 

Share this post


Link to post
Share on other sites

ok. the reason they gave in that post is the same idea my customer thought of when i was asking him at his garage earlier. thank you for the link.

Share this post


Link to post
Share on other sites

Those white plastic rings are called "bump plates" and they are intended as an extra layer of protection for the piston rod seals for when the car compresses fast enough for the bump rubber to make contact with the end of the damper body.  The bump plates have two different designs, one a closed ring with a somewhat waffle shape and the other are flat and C shaped with a gap in one side.  Because bump rubbers are round, fast moving, and soft to compress, it is defintiely possible for a bump rubber impact to the top of the strut to drive a puff of compressed air and possibly some road grit into and past the seal lip and into the damper.  The waffle or C shape gives a path for this to just blow out to the side and help protect the seal that much more.  Because KONI dampers are expected to last a very long time, some extra seal protection can be helpful for longevity.

After tightening the gland nut, the first step of reassembly is to just drop the bump plate ove rthe piston rod then reinstall your bump rubber, dust cover, etc.  The Miata forum thread calls the bump plates "packers" which is a relatively common name from the Oval Track Racing world where you might stack several of them to make bump rubber contact happen sooner for a number of possible reasons but you also risk handling and tire grip issues as well.   The comment about them being related to an old, multi-piece style of piston rod seal is something that the poster has made up themselves.  Yes, in the early to mid '80s there was a change in the seal design (I talked about ti earlier in this thread) but bump plates having some involvement with that is just someone interjecting their own assumptions.  I have explained the bump plate installation and usage many times over 23 years but never heard that one before.

  

 

  • Like 2

Share this post


Link to post
Share on other sites

Our apologies to all of the patient 280ZX owners, sorry for the delay, as Koni had to spend some extra time on the more-difficult-to-create rear units to make sure they were right. As far as we can tell, they went into production in mid-July. After that, sea freight generally takes about 6 weeks to arrive to Koni in the U.S., and then from Koni U.S. to our warehouse about another week or so. If all goes according to plan... then hopefully that means we'll have them in stock sometime after mid-September.

We hope to have images soon, and of course will announce it here when they arrive.

280ZX's are awesome!

spacer.png

Why add this in the early forum? First, just in case anybody missed it, all of 70-78 Koni Sports are in stock and ready to ship! And, we know many 280ZX owners in this forum also have earlier Z's. Gotta love Z enthusiasts!

Share this post


Link to post
Share on other sites

On 7/31/2019 at 12:59 PM, Joseph@TheZStore said:

Our apologies to all of the patient 280ZX owners, sorry for the delay, as Koni had to spend some extra time on the more-difficult-to-create rear units to make sure they were right. As far as we can tell, they went into production in mid-July. After that, sea freight generally takes about 6 weeks to arrive to Koni in the U.S., and then from Koni U.S. to our warehouse about another week or so. If all goes according to plan... then hopefully that means we'll have them in stock sometime after mid-September.

We hope to have images soon, and of course will announce it here when they arrive.

Oops... Guess what arrived in September just like we said? Our apologies for saying we'd announce it when they arrive, and then neglecting to... Since I had to apologize for my error on the ZX forum, figured I'd do it here as well. Besides, maybe there is a 280ZX in your future?

spacer.png

Here they are! The front 280ZX cartridges look and function basically the same as the 70-78. However the rear shock/spring seat version features a little extra. Note that these are designed with a 3 position spring seat perch. So if you know you will be touring often with lots of luggage and want a bit more ride height, you can set them to the top position. If you want them to ride a little lower, set them to the bottom position (they are set during installation, to change the position later, the struts must be removed). Nice little option to have available, thanks Koni!

So now the Koni Adjustable Sport Yellow Struts/Shocks have been completed for all of 70-83 240Z, 260Z, 280Z, and now 280ZX. We've heard some good reports so far where people like how they function, especially with Eibach Springs.

Thanks again to Koni and Lee Grimes (KONI Lee) for all the great work!

 

Share this post


Link to post
Share on other sites
On 4/21/2019 at 4:41 AM, Nils said:

 

Thanks for the replies gentlemen! For clarity, I've collected all info on my setup in this post.

Car: 05/71 HLS30-30267 US model. Two previous owners before me (1971-1979 / 1979-2013). To my knowledge, it's an unmodified/stock car. It came with original open-type struts, springs and strut housings. The struts were leaking so I replaced them with KYB Excel-G's and supplied gland nuts.

Strut housing part numbers: 54303-E4151 and 54302-E4151. I can't find any production date/number stamped on them.

Strut housing dimensions: Inside: Between 15" 1/16 and 15" 1/8. Outside: 16" (slightly difficult to measure precisely atm as they're assembled). It's difficult to see the inside bottom of the housing, but I did take a photo and it looks fairly clean. Can't see any sign of inside spacers being used.

Koni front shock part numbers: 8641 1031SPORT (1-2019)

Gland nut: I first tried with the supplied Koni nuts. I also tried with the original nuts and the two variants of KYB nuts (front / rear). As someone mentioned, the front KYB struts are shorter and therefore user a spacer inside the gland nut.

Strut lengths: The (yellow) housing part of the Konis are 387mm (15 1/4"). The KYBs are 377mm (14,84"). It's also worth noting that the two brands of struts have different bottom shapes - the Koni is convex while the KYB has a concave "cup" welded to the bottom. Depending on the shape of the bottom of the strut housing, ths might affect the fit.

Gap: I curently have a gap of around 8mm between the rim of the gland nut and the top of the strut housing. According to the Koni supplied instructions it should be between 1-4mm. On one side, the threads won't catch at all. On the other side, the threads enter but I only have a quarter turn before it's full stop.

 

Measured distance.jpg

FWIW, I bought a pair of new 240Z front Konis to replace a blown Tokico in my rear Ground Control sectioned coilovers. I had the same gap as shown above and had to return the pair. The Konis are taller than the Tokicos and the struts were sectioned to fit Tokicos. Many thanks to my friend  Jim Karst for selling me some nice used Tokicos, or I would have had to add a section to my strut (PITA). In the future, I would suggest shock tubes err on the side of too short, not too long (much easier to add a spacer to center the shock in the strut).

Share this post


Link to post
Share on other sites
On ‎12‎/‎1‎/‎2019 at 12:31 AM, bingo said:

Does anybody know if these are digressive or progressive?

As with pretty much all KONI dampers, these are digressive valvings on the Z cars. This means that as they initially begin to move, they build damping forces at a pretty steep rate to give very low piston speed, subtle body motion control but the rate of climb continues at a decreasing or digressing rate at target piston speeds across their working piston speed range so that they do not get too firm and causing handling, tire grip, and ride comfort issues once the suspension and body get into significant motion.

A progressive damping curve would normally be a bad thing as it would have very little damping force and control in subtle suspension motions but it would rapidly increase the rate of climb becoming overdamped and harsh over big motions and bumps.  A progressive damping curve on a car would be an extreme rarity and I can't say that I have ever seen such in my nearly 25 years in the business.  

Some cars and specific suspension designs (typically not struts) prefer a more linear damping curve meaning that that the rate of climb is relatively even across the piston speed range and typically have pretty limited initial low speed damping forces.  Some relatively linear damping examples are a number of BMW rear shocks that are mounted well behind the axle and trailing arm with an overdriving or more than 1:1 motion ratio. 

Progressive rates can very often be a very good thing for performance car springs but would be a bad thing for performance car damping. Progressive springs and digressive damper valvings can be very well matched, especially when adjustable.

  • Like 3

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now