KONI Sports & KLA strut mounts

[onZedge]

I searched on this and other forums, but could not find a definite answer. The KLA mounts come with two big washers. One is supposed to go on top of the mono-ball and one on the bottom. The KONI struts come with a lock washer and a nut. When I did a test fit on my workbench, with all the supplied hardware, (WITHOUT THE FACTORY UPPER SPRING HAT), there doesn't appear to be enough available thread left on the strut rod to FULLY accommodate the supplied nut. The nut only threads down to about 70% of its bore - and the spring hat has not even been included in the test fit at this point yet. What have others done when installing this KONI/KLA combination? I am using 200# Weltmeister springs (stock diameter) with the factory upper spring hat.

Things I thought about doing:
-Skip the supplied lock washer & nut and use a nylock locknut instead, but there is still not enough thread to reach the nylock portion of the locknut.
-Skip the supplied lock washer and use Loctite 271 on the supplied nut.
-Skip the supplied nut and use a jam nut (shorter profile) instead.

A few years ago, our project engineering team did some research regarding bolted connections in the ASME standards manuals. The standard stated that at least 1 1/2 threads minimum are supposed to protrude past the top of the nut.

I did e-Mail KLA, but the response was ridiculous and contradictory. It's as if I got a response from Vijay at the Microsoft call center - if you know what I mean.

ALSO, can anyone tell me exactly what the size of the hole in the top of the factory upper spring hat is? A picture would be nice as well.

[Techno Duck]

Its been a few years since i did this, but im pretty sure this is the order i used. Spring perch, spacer washer (one provided with strut mounts), strut mount, spacer washer then nut. Are you using a spring compressor when trying to put this together?

[onZedge]

Originally Posted by Techno Duck

Its been a few years since i did this, but im pretty sure this is the order i used. Spring perch, spacer washer (one provided with strut mounts), strut mount, spacer washer then nut. Are you using a spring compressor when trying to put this together?

I am using an extra 2.5mm washer to "simulate" the spring hat thickness. The hardware sequence you suggest is still about 1.5mm too short of full thread engagement of the nut. I'll probably end up using what you suggested with Loctite on the nut - unless I can find some jam nuts or somebody else has a better idea.

I hate/love assembly issues. It keeps things interesting and the creative juices flowing...

Oh, and yes, I am using a spring compressor. Free rental at Advance Auto. You have to be an idiot to disassemble a strut off the car without one.

[Techno Duck]

Take some pictures if you can. That is strange. Mine have threaded down pretty far..

[onZedge]

Based on the fact that the strut tower brace is mounted behind the bracket, that is a picture of your '87 944 and not your '88 951. Right? I thought so. Well, both of our cars use the same KONI part number (8641-1038Sport) if, in fact, your car had non-sealed struts to begin with. All that being said, the picture you posted should reflect what I have on my workbench.

Not even close, but you have to remember that I haven't dissassembled the struts yet to examine the exact hardware pieces and parts I'll be reusing with the new installation.

I have 35mm available, to the top of the threads, to stack the topworks on:



I'm using one 2.5mm washer to duplicate the thickness of the upper spring hat, and the other 2.5mm washer under the monoball as required by the installation:



The bore of the monoball is 19mm flat-to-flat and the other 2.5mm washer over the monoball as required by the installation leaves me with 8.5mm for the nut. According to ASME, I need 11mm:



The nut is 10mm thick. ASME standards require 1 1/2 additional threads protruding past the nut face for proper tensioning of the bolt (the threaded end of the piston in this case). I am short exactly 2.5mm if I use the 10mm nut. It is important to note that the ASME standards do not exactly dictate the required nut thickness in the context of the referenced standard so a jam nut (5mm thick in this case) would certainly solve the problem AND I would also be able to use the lockwasher KONI supplied with the strut.



I don't think I am being too picky - rather, I'm being safety-concious. Some people would probably have said "ef it" and went with it without question. Producing an industrial standard such as ASME requires time, money and manpower and is produced for a reason. What good is a standard if it's not followed?

[flash968]

looks to me likt the shaft is not fully inserted into the bearing

[Techno Duck]

I was under the impression the spring hat went inbetween the threaded portion and the larger OD of the strut shaft. I cant remember though, its been a long time since ive put mine together.

See what i mean, the spring perch slides down fairly far. This is with the adjustable ride height setup though..the spring perch ID should be the same though.

[onZedge]

...The factory upper spring hat fits at the bottom of the threaded portion of the strut rod. The spring hat is 2.5mm thick. Like I said before, the strut in your first pic is should be the same part number I have. Peculiar.

Anyway, to maximize the pitch and roll of the monoball plate without anything interfering with anything else, I ended up with the following part sequence (from bottom up):

- strut housing
- 25CC light oil (KONI instructions say 50CC - big mess)
- strut
- strut housing nut
- bump rubber
- spring
- upper spring hat
- monoball strut mount
- two 2.5mm washers (supplied with monoball kit)
- Loctite 271
- nut

I'm short 2.5mm of strut rod thread to fully accommodate the 10mm thick nut.

I'll have all the installation pics and notes on the thread found below tomorrow.

[flash968]

something is wrong - either the shaft or the ball are not the right size - have you put calipers on them both? - the larger shoulder of the shaft should bottom out on the bearing, and it does not sound like it is - the threads should be nearly fully exposed when the shaft is in the bearing - no threads should be touching the sides of the inside diameter of the bearing

do not run it like this

[onZedge]

The KONI strut has 35mm available for the topworks (see pic in reply above). The factory strut has 40mm available for the topworks:



The KLA strut mount fits fine (barely) on the factory strut:



The factory strut mount fits fine on the KONI strut:



When you put the KONI and KLA together, that's when you have a problem:



The other issue I have is that with only one washer on top of the monoball and then the nut, the mount housing gets very close to the nut. Too close for me:



Two washers on top gives maximum clearance. The monoball in this pic is mounted directly on top of the spring hat with no washer - I have > 3mm clearance all around, between the monoball and spring hat, no matter what orientation I have the mounting plate in. The maximum limit is dictated by the washer/nut on the top of the monoball due to the design. However, there is not much meat on the 11mm flats to grab on to when tightening the 22mm nut:



The only "warm and fuzzy" solution I can see, is a special nut, like a jam nut, to comply with ASME standard recommendations. Fasenal only lists a Class 4 jam nut on their website (I would like at least a Class 10) - so I have more research to do.

[Techno Duck]

I am taking my front suspension apart later today and will take a few pictures of what i see. I have a feeling something is wrong, likely a wrong part. Have a picture of the underside / spring perch with the KLA mount in place?

[flash968]

the kla mount does not look fine on the factory strut in that picture - it looks like you have the same problem - at no time should any vertically loaded bearing have threads touching the bearing surface - they should be fully exposed

can you take shots of the bottom side? if that 15mm long non-threaded portion of the strut shaft is not fully inserted into the bearing and bottoming out against the bottom side of the bearing, you have found your problem

[onZedge]

Jon, I hope you're not taking your car apart just for me! As you can see in this pic, with the monoball mounted on top of the spring hat and no washer, I have plenty of clearance no matter how far I "wobble" the mounting plate. With the factory setup, the inner bearing race rests directly on top of the spring hat with no spacer or washer. I have no issues with mounting the KLA monoball directly on top of the spring hat with no washer:



Not the greatest pic, but the spring hat and monoball ARE fully seated on the top of the strut rod. Bob, regarding your comment, both the KONI and factory strut have 15mm of unthreaded length available. The end-to-end bore dimension of the monoball is 19mm.



I've seen this monoball hardware question come up on this and two other Porsche bulletin boards. Everyone had lot of questions, but nobody offered a real solution. I hope somebody learns something from this exercise.

[flash968]

hmmm - have you taken a measurement of the thickness of the oem bearing and the kla, and compared them? it seems then that the kla unit must be a lot thicker than oem

[onZedge]

KLA monoball is 19mm thick; two washers @ 2.5mm each; total is 24mm
OEM strut mount is 17.5mm (compressed) including the conical washer on top

KONI strut - shoulder to top of threads is 35mm
OEM strut - shoulder to top of threads is 40mm

So that's the problem. The KONI strut threads are 5mm shorter than the OEM strut. The KLA monoball is 6.5mm thicker than the OEM strut mount. Things just happened to add up the wrong way.

Class 8 M14X1.5 jam nuts have been ordered from Fastenal. It's the only final solution to meet ASME recommendations that I can see. Period.

Attention to little details like this, with the two 280Z racecars we built, were contributing factors to our three consecutive regional championships (SCCA NER GT-2). I'm sure of it.

[flash968]

but that also may not meet the thread tension spec - there is a minimum number of thread engagement you must have, based on the diameter of the shaft, whether it is course or fine threads, and the material of the shaft and the nut

based on what i am seeing, i don't think you can safely run those monoballs on those struts

serious bummer, because i was thinking about changing to those myself

i would call scott at kla and find out what is going on there - he is great at resolving issues, and very easy to deal with

[onZedge]

I am aware of these issues as well. Our engineering team had a similar issue with poppet valves mounted on top of a baghouse at a power plant. The mounting flanges were much thicker than the architectural drawings showed, so the previously installed weld studs were too short for complete thread engagement of standard nuts. Based on factors such as stud and nut material, expected wind loads, required fastener assembly tension etc., the jam nut solution I came up with was deemed suitable for that application by our mechanical engineer (I was the electrical/I&C engineer). Saved big bucks too: 4 studs per poppet X 5 poppets per baghouse compartment X 16 compartments per baghouse X 4 baghouses is a LOT of R&R for new longer studs. Like I said, I have more research to do. The jam nuts I'll be using on the KONI struts are a solution, but not the solution until I can verify the loads. A bolt must be fully engaged by a nut for proper tensioning. The jam nut solves this. Now I wish I didn't sleep through the "Strength Of Materials" class in engineering school!!

After sleeping on it, a Class 8 or better flanged nut used without the extra top washer is the ideal and final solution. Finding this particular fastener however, will not be easy.

[toolboy62]

I replied earlier but it appears to have been munched - can you machine a little "pocket" in the monoball's housing around the nut so that there is space for the nut to move a little bit as the suspension works? then you can get rid of the washers altogether assuming that there's nothing that I'm not seeing...

nate

[flash968]

the rule of thumb is the length of threads should be the same as the diameter of the screw - a jam nut won't hold full torque for long in this application - the pounding on the threads will most certainly wear them - the good news is that you will probably hear it or feel it when they get loose

eliminating the washer is a problem because then the nut is on the bearing itself, this means that as you tighten the nut, the bearing will turn too, thereby limiting the ability to tighten the nut to the correct torque without the shaft turning

i think the better solution is to find a higher grade, thinner washer - the trick will be finding one that is the right diameter

if it makes you feel any better, bilsteins are worse

[toolboy62]

it looks from the pics like the Koni shaft has flats on it for a "shock wrench" to hold the shaft from turning while torquing the nut... haven't installed a set of Konis for quite a while tho so I can't remember if this is true or you need a tappet wrench

nate