Koni woes

Chuck Branscomb · **Posted:** Mon Jan 17, 2011 3:34 pm

23k miles of use over the past 3 years and both rear Konis on the E46 are knocking pretty loudly over high frequency bump inputs. I've seen others here complain about Konis recently, but my experience with them over the past 30+ years has been fine until now. FWIW, I never ran these at the extremes of adjustment -- on street they were set to 3/4 turns off full soft, and at autox usually 2 turns off full soft.

It's interesting that they both started knocking within about 3k miles of each other. The right side was not nearly as loud as the left though.

These are custom built Konis for TC Kline for the E46 with top adjust knobs. TCK will process a warranty claim with Koni, but they say that the backlog at Koni right now is 8-12 weeks. They have offered to send me some new ones in place of these on return, but they won't have those in stock until mid-March or so.

Anyway, shipped off the shocks today. Thankfully I kept the oem shocks as they're back on the car now (and have way too much compression damping btw).

So I've been had by the Koni curse I guess...

JamesShort · **Posted:** Mon Jan 17, 2011 3:43 pm

Well, at least you only have 1 out of the 3 bad signs that Lee told me during my problems:

1. noisy
2. leaky
3. adjusters don't work properly

Mine had ALL 3 issues at once

.

Sorry Chuck. They had a wicked backlog when mine had problems, but I got squeezed into the queue given the circumstances.

Chuck Branscomb · **Posted:** Mon Jan 17, 2011 3:48 pm

What was the outcome? Did you get them repaired and all is fine now?

JamesShort · **Posted:** Mon Jan 17, 2011 4:01 pm

Chuck Branscomb wrote:

What was the outcome? Did you get them repaired and all is fine now?

Front driver insert: leaking, 1.25 turn of adjustment instead of 2.25, and noisy -> replaced with new one
Front pass insert: Adjuster jammed to 0.5 turn of adjustment, noisy ->replaced with new one
Rear driver: clunking in compression due to debris jammed in a compression valve but rebound was fine which causes an abrupt dynamic and a lot of noise -> rebuilt and sent back to me in 1 week along with a dyno plot

The other rear damper was fine and still is. It was a real bitch of a time, but I'm very satisfied with the shocks and the way I was treated. Maybe the name dropping of Karl helped me out. But now I have Lee's personal cell number in my phone due to all the calls I had with him

.

Donnie Barnes · **Posted:** Mon Jan 17, 2011 8:07 pm

First, Koni-NA is ALWAYS backed up like that. Never expect anything different. And I know of no other shop I'd trust with those shocks. Sucks.

Second, you sure it is the shock? I only ask because mine were making a noise (Koni singles on the 330i ZHP I recently got) that sounded like that old-school "your door is ajar and clunking over a bump" kind of noise. Both sides, but it started at different times, rear only. My guys looked into it (one of whom is kind of a BMW expert) and while I don't even remember or claim to know exactly what was up, it had to do with shock mounts and some "bushing" that always wears out in the BMW mounting. They replaced it with an upgraded part from Turner, I think, and life is good now. I've got no idea how many miles the Konis on my car have, though.

You're obviously a BMW expert, so I'm guessing you know what you're doing on this, but I thought I'd mention it. My guys had literally *just* reinstalled those shocks a few weeks prior (Keith had taken them off thinking he'd need to return the car to stock to get it sold easier when I bought the whole package from him), so I assumed they did something wrong at first. You probably know what I'm talking about better than I do, though, and have already ruled that out. But just in case...

--Donnie

JamesShort · **Posted:** Mon Jan 17, 2011 8:19 pm

When my rear was clunking Lee told me he'd bet every dollar in his wallet that it wasn't the shock which implied I installed it wrong. After taking apart and putting it back together 8 times including swapping sides it turned out to be the shock

.

However bushes on bimmers are generally problem points so Donnie's idea seems quite probable.

Chuck Branscomb · **Posted:** Mon Jan 17, 2011 9:04 pm

Good point Donnie -- I inspected the top mounts, removed them from the shocks, etc, and couldn't tell any difference compared to new. They look great. However, I suppose that obviously doesn't totally rule them out.

Here's the ones on the Konis:

http://www.tcklineracing.com/webdocs/Items/Details390.cfm

They literally look and feel brand new but of course that doesn't mean their dynamic properties under load aren't degraded. Sigh...

These are for the larger diameter top adjust shocks, so I didn't even think of trying them on the stock shocks (don't think they'd work) (not that that would necessarily conclude anything since the dynamic force input from the stock shocks would be different, but if they did clunk on the stock shocks...).

I guess if/when I get a new/rebuilt set back and they clunk right away I'll know it is these low mileage top mounts, but TCK didn't even bring up the subject.

I think Keith had enlarged the stock bushings maybe as opposed to using something like these TCKs? I don't think these are stock class legal per se (but we've been autoxing in STX for a while now anyway -- hope they are legal there).

Chuck

Donnie Barnes · **Posted:** Mon Jan 17, 2011 10:39 pm

Well, if they had looked or felt bad my guys would have noticed it at install time, but didn't. Then when I pointed it out one of my guys said "shoot, yeah, that's the sound those top mounts make when they wear out, and on the E46's they don't last very long at all." Then they replaced them and the clunk was gone.

I don't recall for sure, but I think Keith said he realized later that what he had done may not technically be stock legal. *shrug* I never cared since I'm not going to autocross it anyway...

--Donnie

JamesShort · **Posted:** Mon Jan 17, 2011 11:12 pm

Drilling out stock top hats is stock legal so long the hole is concentric to the original.

Arthur McDonald · **Joined:** Fri Aug 29, 2003 1:54 am **Posts:** 2052

Dumb question #23 -- are you running stock ride height? If not, were the shocks shortened to match? (I know this can be death on struts, not sure about shocks)

Donnie Barnes · **Posted:** Mon Jan 17, 2011 11:43 pm

JamesShort wrote:

Drilling out stock top hats is stock legal so long the hole is concentric to the original.

This much, I know. BTDT on many occasions. I think there was something else, though.

I do recall Keith saying these were *not* the "normal" Koni singles, but some special ones that had the adjuster on top. Apparently the normal singles would have the adjuster where you can't actually adjust it with them on the car or something. But that's all from bad memory in talking to him and never having actually seen how ANY of this goes together myself. So I may not be helping at all.

--Donnie

Chuck Branscomb · **Posted:** Tue Jan 18, 2011 7:11 am

Arthur McDonald wrote:

Dumb question #23 -- are you running stock ride height? If not, were the shocks shortened to match? (I know this can be death on struts, not sure about shocks)

Yep, stock springs/height.

Re stock class -- I'm pretty sure Keith drilled stock bushings to remain stock class legal. Stock bushings are pretty much wasted in short order when used with shocks that are significantly stiffer than stock -- heck, they're usually done for by 50k miles or so with stock shocks. I think on the 135i that Keith was co-driving the stock rear shock bushings die even faster when you install Konis and run them very stiff as the newer cars have a large bushing on the bottom side that can't handle load inputs that are probably a multiple of the factor of safety of the design.

We'll find out the answer in a couple of months I guess when I get the shocks back. The fortunate thing is that these are really easy to remove/replace -- just three bolts. The hardest part is the 10 min you have to spend removing coverings and panels in the trunk. With my wife helping, it took less than 45min start to finish to put the stock ones back in.

Re "not normal Konis" -- that's right Donnie. These are the top adjust Konis for the rear, and apparently they're only available through TC Kline. The shock bodies have a TC Kline Racing marking on them along with the rest of the manufacturing info. They have a 12mm top shaft diameter (where the large shock shaft necks down the mounting diameter) as opposed to a 10mm one like the "normal" Konis and the stock shocks.

JamesShort · **Posted:** Tue Jan 18, 2011 10:11 am

Yeah, normal e36/e46 Koni's are adjustable only by compressing the damper shaft all the way and then spinning it......given how easy it is to install on the rear of bimmer suspension, I don't think this is terrible. But externally adjustables sure are nice

.

MarcusMcRae · **Posted:** Tue Jan 18, 2011 10:40 am

Ground control also sells the top adj. The rear shocks I got from them for my M3 had a part number that also fit the NSX.

DickRasmussen · **Posted:** Tue Jan 18, 2011 11:59 am

Questions for my engineering education since I'm hoping these "issues" are mostly due to engineering tradeoffs and packaging constraints:

1) Koni shock failure: What actually fails and "why" other than totally unacceptable "out of the box" failures? Is this a design or manufacturing "weakness" or a result of the constraints of the available shock construction conflicting with durability with the required "stiff" valving/adjustment ability?

2) BWM shock mount failure: What is so special about these parts that they have limited life "before noise" when used with stiff shocks? Are these "rubber" failures or "metal" failures, or something else?

Thanks,

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