KONI Sports for Classic Z's

[Carl Beck]

2 hours ago, dutchzcarguy said:

Nice Carl, Thanks.. So the 240z has 2 different spring rates in the front.. i learned something! ?

The different positions could be either a spring rate difference - or a difference in Free Length. The corner weight could be 635 lbs on one side and 685 lbs on the other for example. So if the spring rate is the same, then you would use a slightly longer spring on the heavy side - so that both side would wind up with the same 'installed length". Most of the Factory Service Manuals give you the Spring Rate (constant), the Free Length and the Installed length.

 

Edited February 14, 2019 by Carl Beck

[KONI Lee]

14 hours ago, Lumens said:

Looking at one of my old Koni's and I do mean old, it shows 8641-1031

and underneath that it reads 8703.

I am going to call to see if I can send in all 4 to be tested. The adjustments seem to have quit working.

Looks like Week 3 (January) of 1987 production.  Being the 8641 prefix, they are the externally rebound adjustable, twin tube low pressure gas version that were made  for a few years in the 1980s.  I believe that the 8641 versions were likely made primarily (and maybe solely) for the North American market and likely even built in a US factory in Virginia that operated from about 1982 through 1989 or so.

If the adjusters are not turning (probably from jamming  by hand or impact tool or internal bottoming most likely), then dyno testing them will be of no value and wasted money and time. Additionally, whomever tests them will need to have a dyno with fixtures to hold the Z-car's uncommon spindle attached strut housing. They could likely be rebuilt but it would actually be much cheaper, faster and have a full warranty if you were to simply purchase the brand new ones from Motorsport Auto.  You would be much farther ahead to start with fresh ones than pay the labor and parts to fix the old ones which would still not be entirely new.   It is definitely less expensive per unit to build new in a large production batch than rebuil;d them onesy-twosy paying for labor and parts.

[gundee]

KONI. ?

[dutchzcarguy]

19 hours ago, KONI Lee said:

What is interesting to me is that the 1980 date code on the newer design means that they must have started that conversion earlier than I'd thought.

I also noticed a difference in color.. (They have been cept in a box in the dark and conditioned.) one day i'll install these as they are on my 240z (i hope) and we'll see what happens !!

[HS30-H]

22 hours ago, dutchzcarguy said:

As said earlyer, these Koni's are new old stock.

I've heard that these were the shocks that where used in the south african rally cars?

I don't know where you heard it from, but it's not correct.

None of the factory works rally team 240Zs used KONI shock absorbers.

[HS30-H]

Here's an old set of Made in Holland KONI conversion inserts for UK/European market '240Z' models which I used to own:

[gundee]

23 hours ago, KONI Lee said:

If the adjusters are not turning (probably from jamming  by hand or impact tool or internal bottoming most likely), then dyno testing them will be of no value and wasted money and time. Additionally, whomever tests them will need to have a dyno with fixtures to hold the Z-car's uncommon spindle attached strut housing. They could likely be rebuilt but it would actually be much cheaper, faster and have a full warranty if you were to simply purchase the brand new ones from Motorsport Auto.  You would be much farther ahead to start with fresh ones than pay the labor and parts to fix the old ones which would still not be entirely new.   It is definitely less expensive per unit to build new in a large production batch than rebuil;d them onesy-twosy paying for labor and parts.

 A. Why would not the US Koni rebuild and test facility no have fixtures to test a simple common design Koni?

B. Why buy new? These are a lifetime replacement warranty.

[Patcon]

1 hour ago, Lumens said:

 A. Why would not the US Koni rebuild and test facility no have fixtures to test a simple common design Koni?

B. Why buy new? These are a lifetime replacement warranty.

I suspect there are a lot of warranthy exceptions for damage or normal wear. Most of these warranties are for material defects

[KONI Lee]

2 hours ago, Lumens said:

 A. Why would not the US Koni rebuild and test facility no have fixtures to test a simple common design Koni?

B. Why buy new? These are a lifetime replacement warranty.

 

A.  There is no longer a KONI North America Automotive damper service facility as it was integrated into our Railway shock service facility several years ago.  There are 3 outside businesses that are authorized KONI Automotive rebuild facilities in the US and their info is listed in the right side column of this link that can do testing and service for you: http://www.koni-na.com/en-US/NorthAmerica/Locator/  but you will have to pay them for their work. The Datsun Z strut with the attached spindle (used sometimes on ‘70s cars like RX7, 2002, etc. but rarely used since) is neither common nor simple so most companies with shock dynos do not have proper fixtures for strut housings, much less ones with spindles attached.  We have a special dyno fixture for inserts which must be compressed within an outer structural shell for testing but that is very uncommon outside a company like ours.

B. If you bought them brand new and have a purchase receipt in your name, have a current vehicle proof of registration still in your name, and there is an identifiable internal manufacturing or materials defect in the damper that is causing the problem, then it certainly is a candidate for warranty replacement for as long as you own them.  Because those dampers were discontinued 25+ years ago, that causes some complications but they can be addressed.  The warranty does not transfer to a non-original KONI purchaser, if sold on the car to a new owner, does not cover non-defect damage caused by external means (bottoming damage inside from hitting something, incorrect installation or usage damage, etc.).  In my 20+ years of experience, stuck adjusters are almost always of external cause and not internal defect cause.  It could theoretically be stuck from a defect cause but that is extremely rare and also extremely unlikely to happen to all four of the dampers in a single car set.

 

Your comment about having them tested and possibly serviced made no reference to defects or warranty so I commented based on that.  If someone is going to pay for service to be performed, the labor and parts cost will almost always cost more than a brand new one if an off-the-shelf modern replacement is available and you do not need a customized unit for racing, special needs, etc.  If the above warranty info fits your situation, then KONI North America will be happy to address it that way.  Most people 30 years later likely don’t fit that so a modern updated version is often the cheaper, faster, and better route for the future.

[Carl Beck]

On 2/13/2019 at 3:48 PM, KONI Lee said:

The new MSA Sports are twin-tube low pressure nitrogen gas charged (8641 prefix with the 4 indicating low pressure gas charge) and the Classics are 86 (twin-tube hydraulic non-gas charged).  Generally an increase in internal gas charge can have a pretty minor if any increase in static ride height and can vary from car design to car design, I think your 1 inch comment might be overestimated as most cars are more likely to see 1/4-1/2" difference with several variables involved.  Any static height changes are going to be related to a mix of things including the amount of gas charge itself (from zero gas charge to low pressure gas charged (3-5 Bar usually) to a mono-tube high pressure gas charge (10-20 Bar usually) in addition to vehicle weight, spring rates, damper piston rod diameter (effect is more on a large rod diamete, less on a small rod diameter), suspension geometry, etc.  How well and consistently you make your before and after measurements and do the installation may likely have a greater impact on a  height change than actual internal gas pressure difference. 

KONI is one of the few companies who makes all three different shock designs  (T-T non-gas, T-T LPG & M-T HPG).  Very few people understand what internal nitrogen gas really does or doesn't do in a damper however the gerenal public's limited info perception (mostly old ads from mass market, commodity shock brands) is usually that gas charged is better than not gas charged so often we will include a small gas charge to satisfy that "Is it a gas shock?" question if we don't have the abulity to discuss it technically.  In fact, we are working on a KONI video script now addressing the very common misconceptions of gas charging  or not.

Hi Lee: Great to have you here for this discussion. A further comment about our experience with gas pressure shocks several years ago.  Front corner weights on the 240Z’s were 562 lbs and 604 lbs for 1972 as an example. (and varied a little 70/71).

 

We measured the load it took to compress the Tokico Gas Pressure Shocks (non adjustable) at 80 psi. at a local machine shop.  So it was easy to see that a 240Z with a spring constant of 83 lbs/in wound up sitting about 1” higher after installation. As for taking accurate and comparable measurements - a lot of the people involved are Engineers and pretty picky about accuracy. So lets hope your new offering are closer to the 3 Bar than the 5 Bar. At any rate better to know in advance of installation, so any necessary adjustments to spring rates or installed length can be made ahead of time.

[gundee]

9 hours ago, KONI Lee said:

Your comment about having them tested and possibly serviced made no reference to defects or warranty so I commented based on that.  If someone is going to pay for service to be performed, the labor and parts cost will almost always cost more than a brand new one if an off-the-shelf modern replacement is available and you do not need a customized unit for racing, special needs, etc.  If the above warranty info fits your situation, then KONI North America will be happy to address it that way.  Most people 30 years later likely don’t fit that so a modern updated version is often the cheaper, faster, and better route for the future.

Was not aware Koni outsourced their services. I did in fact buy them new in 1978 and I still have the receipt.

I am in no way going to pay someone else $400 plus to check them. I will chalk it up to another lesson learned.

Thanks anyway.

[KONI Lee]

On ‎2‎/‎15‎/‎2019 at 11:11 PM, Lumens said:

Was not aware Koni outsourced their services. I did in fact buy them new in 1978 and I still have the receipt.

I am in no way going to pay someone else $400 plus to check them. I will chalk it up to another lesson learned.

Thanks anyway.

KONI is not outsourcing any services.  We handle our warranties internally (replacement with brand new dampers when possible) and we still build our own prototypes and our own internal damper work as needed.  We no longer offer automotive damper rebuild/revalve services to consumers directly ourselves because far less than 0.1% of KONI dampers ever get serviced and there are three independent outside companies who have decades of experience at it.  It's just like an independent auto mechanic shop servicing someone's car except that we first require significant  training, tools and component parts for them to be authorized.  

When we offered it, complete dyno testing was usually about $30 each to cover the time required for testing and that was waived if the there proved to be an issue that required internal service work.  Since your stated that your adjusters are stuck, I would see no use to dyno test  them because we already know that some internal service would be needed to get them fully functional.  If the adjusters are stuck because the damper bottomed internally (similar to bending engine valves by hitting piston tops if you break a timing belt in an "interference" engine), then the ends of the piston rods will be bent and the compression valve cartridges will be damaged.  Replacing those parts would further raise service costs far above the price of brand new.  Its all about the best balance of time and money to get to your desireed end result.

Making a KONI warranty claim is something completely different and not connected to having your existing dampers serviced by one of the outside shops.  If you meet the warranty criteria (which it sounds like you do since you bought them new and still have the car), then we can start a warranty claim by using that link  posted above to get the shocks inspected to see if the issue is warrantable or not.  Once inspected and the trouble root issue is identified, then we follow the best path for resolution from there.