non-rebuildable Koni rebuild

[tadd]

I prostrate once more infront of the great pelican hive mind for answeres...

I was getting ready to order new inserts and had a 'what the hell moment' and chucked the 82R-1394 shock in the lathe and cut 80 thou off the top of the case to remove the three 'peened over' sections so the thing would come apart.

This is what I got, minus all the nasty grunge the oil had turned into... there was like almost nothing liquid to pour out.



Its clear the insides are a fixed length to the outside tube, so re-assembly will require the inside tube to be shortened by 80 thou too so as to allow a bit of material to 'peen over' again. It looks like all the load is carried by the threaded insert nut into the strut housing, so the insert length is not critical (ie rests on the bottom of the strut housing).



That said, everything inside looks pretty good. There is some very, very light scoring on the bearing surfaces and the main o-ring is toast (one viton oring via McMaster). This should be rebuildable...

So my question is how much oil goes in one of these things and what weight would be suggested? There wasn't poop to measure. My yamaha dealer has quite a selection of shock oils which I am sure are far better than the original stuff turned to goo that was in there.

Thanks in advance....

t

[Porboynz]

Maybe the weight difference between a good one and your disassembled shock would give an idea of the oil volume?

[Flieger]

He wants the viscosity, the inserts are filled until there is no air in them I would assume, since bubbles would compromise the damping.

[daniel911T]

I have an identical pair of those under the front of my car.

Subscribed!

...and good luck.

-Dan

[tadd]

Flieger:
Is that true... Filled full? Won't that just lock solid? There was always an air gap in bike forks. The oil has to have somewhere to go. Nothing wrong with an air/oil emulsion, hence the high pressure gas shocks.

The very early shocks didn't have inserts. I've looked for the fill volume on these but haven't found the value yet.

Thanks for the replies so far!

t

[Joe Bob]

Talk to Chuck Moreland, Elephant Racing

[tadd]

Looks like it's the twin tube design...

http://www.koni-na.com/pdf/tech.pdf

t

[RaceProEngineer]

Please do not accuse me of brilliance here, but Koni's telephone number is 800-922-2616, and Lee Grimes' extension is 316.

Or, I guess you could have Chuck call them and find out . . . . .

Ed LoPresti

[Flieger]

There are several designs for dampers. High pressure gas charged ones (always?) use a piston between the gas and oil. The pressure of the nitrogen on the piston eserts a pressure on the oil which keeps it from foaming and also allows the volume of oil to change as the piston rod goes in and out of the chamber, taking up space. A twin tube design has concentric cylinders with a restrictive valve between them so that the inner tube is full of fluid but the overflow when the piston rod enters the damper chamber can go through the restrictive valve and into the outer tube which has low pressure in it (atmospheric).

I am not exactly sure how these are constructed but I know it is not gas-charged.

[1-ev.com]

Subscribed!

Hey Guys,

Sorry for silly question,but I could not find how to adjust Koni front struts. Do I have to unbolt top from the car?

Also, how can I identify my Koni strut model?

Do I have non-rebuild one?

Also, if anyone can tell me what kind inserts are in there?

Thank you.
-Youri

[donald]

I am trying to rebuild the rear Koni's on my 72 (The part number is 82k 1756). I have emailed Koni on several occassions and received some support. I didn't get everything I needed, but I did get some useful info:

From "Jason - ITT Motion Technologies Harrison" "For what it would cost you in parts to rebuild that damper you may be able to just buy new ones. The problem when you get that apart is that most likely it is going to have a solid steel piston inside(we no longer use them)and the inner cylinder and piston are both going to be gouged and have scrape marks which is going to allow oil to flow past the piston and low forces. Also there is a plastic rebound stop inside that usually melts away over time and pieces get stuck in the foot valve which controls compression and the foot valve is no longer good(you can not take it apart and clean it). A lot of parts have been updated in our dampers and all our new dampers now have banded pistons, our new style guides have a rubber seal and wiper in the top instead of packing inside, new material for the rebound stop and different foot valve design.
With the damper being that old you are going to want to test it afterwards to make sure it is actually working before you reinstall it on the car."

I have 2 sets and I am looking at rebuilding one of the sets. One set has less than 60,000 original miles on them. The first set still has clean oil in it. I can measure the amount if you can't find the volume needed. Also, according to Jason: "We use a special fuchs shock oil. i will have to search out old books to find the amount that goes in that damper. " I never did get the volume from him.

Finally according to Jason "The o-ring dimension in the book says its 44.04X3.53 that is Millimeters the 44.04 will be the O.D and the 3.53 is the thickness. You may not be able to find that exact size but anything really close to that thickness will work. Check mcmaster they usually have a lot of the o-rings we use or use to replace the old ones we can not get from Holland any longer. I would buy either Viton or buna rubber."

I did find the orings locally for less than $1 each.

I will keep checking your post. I am hoping you find more info that I can also use.
GOOD LUCK

[RaceProEngineer]

Originally Posted by 1-ev.com

. . . . .Sorry for silly question,but I could not find how to adjust Koni front struts. Do I have to unbolt top from the car?

Also, how can I identify my Koni strut model?

Do I have non-rebuild one?

Also, if anyone can tell me what kind inserts are in there?

Thank you.
-Youri

Youri,

That photo looks more like a Bilstein to me than a Koni. But assuming it is, in fact, a Koni, then those are "Yellows" - track shocks.

Next, assuming that you actually mean adjust your front dampers, and not adjust your struts, there is a short blade in the center section on the very top of the damper. It is visable, and easily accessible under the hood of a 911. Turning that blade adjusts both bump and rebound resistance, in a 1-to-3 ratio, but it is counter-intuitive. Turning clockwise REDUCES both bump and rebound resistance, while turning counter-clockwise INCREASES resistance. Koni provides a handle which engages that little blade, but if you did not get one with your car, a pair of small vice-grips will work.

If these are Koni Yellows, thousands are rebuilt each year - no problem. (Likewise if they are actually Bilstein.)

Ed

[bulitt]

"Its clear the insides are a fixed length to the outside tube, so re-assembly will require the inside tube to be shortened by 80 thou too so as to allow a bit of material to 'peen over' again."

I find the older I get the chance of my repair outliving me becomes a real possibility. Tack weld the tops.

[1-ev.com]

Originally Posted by RaceProEngineer

Youri,

That photo looks more like a Bilstein to me than a Koni. But assuming it is, in fact, a Koni, then those are "Yellows" - track shocks.

Next, assuming that you actually mean adjust your front dampers, and not adjust your struts, there is a short blade in the center section on the very top of the damper. It is visable, and easily accessible under the hood of a 911. Turning that blade adjusts both bump and rebound resistance, in a 1-to-3 ratio, but it is counter-intuitive. Turning clockwise REDUCES both bump and rebound resistance, while turning counter-clockwise INCREASES resistance. Koni provides a handle which engages that little blade, but if you did not get one with your car, a pair of small vice-grips will work.

If these are Koni Yellows, thousands are rebuilt each year - no problem. (Likewise if they are actually Bilstein.)

Ed

Ed, Very Big Thank You for your input.

I think this is Koni, if you look at the pic, very left on the strut it said "NI" before "SENS" as part of Koni word, it just was on the edge and did not get to the pic

Also, they are red color, are they could be yellow design?

Also, question... My car is 68 and on those struts it said 10-69, but previous owner clams those are original...

How it could be? The car has S-Calipers, I think those were started in 69.

Unless, they bought it in 1969 then installed struts and Calipers right before the purchase, or they just upgraded front end to 1969 recently all together...

One, more question about the Rust, do you think this could be removed by sand blaster or other rust removal or they should be replaced all together.

I will post upper Pics later today, to see if it has a short blade in the center section. I know it has round metal cover over top of the strut.

Quick searches show this links:
ID this strut housing please.

http://www.early911sregistry.org/forums/archive/index.php/t-51170.html

Thank you again in advance.
-Youri

[RaceProEngineer]

Well, Youri, I guess I was wrong on all counts! Brand, AND color!

If these are Koni "Reds", then please do not bother looking for any blades on the tops of the shocks - there are none. In order to adjust these, one must disconnect one end or the other, so that one may rotate the shaft inside the shock body.

Koni Reds were a great damper in their day. While shock technology has come a long way in the past forty years, many racers STILL do not yet understand the huge advantages of dampers that are adjustable, as yours are.

I am uncertain whether Koni still rebuilds the older-style (1970s) Reds, and even if they do, whether it makes economic sense to do so. Here again, a quick telephone call to Lee Grimes at 800-922-2616, extension 316, will give you all the info you need.

If the rust is just surface, then sand paper or paint remover will work, being careful to not get either on the shaft or in the internals of the body. I would sand or peanut blast ONLY IF they were completely dismantled, because either process would ruin those shafts and sleeves! You probably already know this, but it is a good idea to use very high-temp paint on racing shocks, again ensuring that none comes in contact with the shafts or body internals.

Sorry for the MISinformation the first time through.
Ed

[1-ev.com]

Originally Posted by RaceProEngineer

Well, Youri, I guess I was wrong on all counts! Brand, AND color!

If these are Koni "Reds", then please do not bother looking for any blades on the tops of the shocks - there are none. In order to adjust these, one must disconnect one end or the other, so that one may rotate the shaft inside the shock body.

Koni Reds were a great damper in their day. While shock technology has come a long way in the past forty years, many racers STILL do not yet understand the huge advantages of dampers that are adjustable, as yours are.

I am uncertain whether Koni still rebuilds the older-style (1970s) Reds, and even if they do, whether it makes economic sense to do so. Here again, a quick telephone call to Lee Grimes at 800-922-2616, extension 316, will give you all the info you need.

If the rust is just surface, then sand paper or paint remover will work, being careful to not get either on the shaft or in the internals of the body. I would sand or peanut blast ONLY IF they were completely dismantled, because either process would ruin those shafts and sleeves! You probably already know this, but it is a good idea to use very high-temp paint on racing shocks, again ensuring that none comes in contact with the shafts or body internals.

Sorry for the MISinformation the first time through.
Ed

Ed, NO NO NO no need for apology at all !!!

I am very appreciated for any info I can get

I just wanted to ask if my Koni-Red containing an inserts or not.

I have seen that 86--1308 struts has been listed as for 65-68 911's fits ...

Thank you.
-Y.

[tadd]

1-ev.com
The date code is 69 so i'm going to go out on a limb and say that they are 'non-rebuildable' inserts. The early konis that are 'user' rebuildable are very early (pre 66 IIRC).

From what I have gleened trading a few emails is that Koni cuts off the outer body (as I did), cleans, inspects, then reassembles but uses a new outer body.

While they are in there, they replace the foot with a new teflon coated one along with replacing the upper leather packing disks with a new o-ring design.

They can also tweak the shim stack/springs in the foot valve to change the compression/rebound damping curve.

I've had no luck on anyone telling me the actual fluid volume, but have read on several other early car forums to fill, try stroking several times, feeling for dead spots. Repeat until success. ATF was suggested several times as the working fluid, but given that specific weight shock oils are avaiable ill use those.

t

[1-ev.com]

Thank you guys !!!

[ajwans]

Tadd, can you comment on whether this was a success longer term? Any problems since you put these back together?

andy

[Jagshund]

^^^^^ What he said. Times two.