KONI Sports for Classic Z's

[Zed Head]

2 minutes ago, DangerBoy703 said:

that is the same picture that came with the Koni yellows i just unpacked today. so do i, or do i not, put anything in the tube?

@KONI Lee should know.  I'd say it doesn't matter.  Maybe he knows why the instructions show 50 mL of mystery fluid poured from a coffee pot.

[Terrapin Z]

I rescind my advice, and concede with the experts here on the forum. I humbly offer this opinion though.

The ones without oil that I have run across, are rusted inside the tube. The opening at the gland nut, is in no way water tight. 

I would put some type of oil (or grease) in there, enough to fully cover the body of the strut but not spill out (50ml, 230cc, or 229cc or 233cc or 49.8 ml), no way to be exact. Some stays in the coffee pot when you tip it.

I am sure you will find a suitable answer and proceed with the upgrade.            

[Zed Head]

They might have a reason.  They just didn't explain it in the instructions.

Here's KYB's - https://www.kyb.com/knowledge-center/shock-tech-for-pros/installation-tips/strut-cartridge-installation/

[grannyknot]

10 hours ago, Zed Head said:

It serves no real purpose and just makes things messy. 

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. 

[Zed Head]

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?

[Nils]

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.

 

[gundee]

Here is photos of my front Konis from the 70's.

What we had to do was just grind a small taper at the bottom as shown for best fitment.

[Zed Head]

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.

[Nils]

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?

 

[Patcon]

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

[Nils]

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.

 

[KONI Lee]

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.