Suspension struts with replaceable cartridges

Dr.Jeff

Dr.Jeff

True Classic
The earlier X1/9 suspension struts had a removable and replaceable insert or cartridge (the "shock" portion of the strut). At one time Koni offered inserts for them, but those are all long gone. KYB also offered some and that was back when KYB still used the high-pressure monotube design (aka Bilstein type), but they too are NLA. Seems like there were other choices also listed specifically for the X1/9 application as well, however like the rest of them you won't find any now.

I recall there had been a couple of options discovered involving the use of inserts from other makes/models. One that comes to mind was units for the old VW Rabbit. I never understood how that could possibly work as the Rabbit inserts are a couple of inches longer than the X1/9 ones (I have old Rabbits and compared them). Maybe someone knows how that was done. Or does anyone know what other inserts (for other vehicles) will work in the early style X1/9 struts? The goal would be something that is still available.

Thanks for any input.
 
You can review this thread. Somebody using your name was in there discussing. :)

Sadly, there are dead picture links. Maybe Doug still has the pictures and can edit and repost? Doug?? You out there??
 
JimD said:
You can review this thread.
Click to expand...
Thanks Jim, appreciate the link. :)

To be honest I'd forgotten about some of the content in that thread, so it was interesting to review it again. However it is a very different topic; that thread discusses modifying complete strut assemblies (housings and inserts) from another vehicle to fit the X1/9. My current question is about finding inserts (dampener cartridges) from another vehicle that will fit into the stock early style X1/9 housings. I know it sounds like the same thing but is actually very different. In the case of Doug's project, the inserts are from the same housings that were modified to be used as complete assemblies. So those inserts already fit those housings, all of which are from another donor car. In the current situation the housings will remain X1/9, with just a different insert installed from a donor car. So they have to fit the Fiat housing and not the ones from the donor car. And the housings from a Rabbit (in Doug's case) are not close enough to the X1/9 ones to use just the VW inserts.

Hope all of that made sense and explains why it is a different scenario. ;)

Another factor that is important to me is the overall length of the strut and insert. I will be lowering the car, so ideally a shorter insert can be sourced to allow the whole strut assembly to be shortened. That will facilitate lowering of the X without sacrificing too much suspension travel. It is easy to modify the housing (if needed) to be shorter. But it is very difficult (impossible?) to make a longer insert shorter. So finding a insert that is the same as or shorter than the original is the goal, not one that is longer (such as the Rabbit).
 
I did find another reference to this subject. It listed two Koni part numbers (front + rear) that are supposed to be direct fit replacements for the X's housings. The reference also said those P/N's were for a Mitsubishi Lancer application. However when I searched the P/N's themselves, the fronts came up as Mazda RX7 (Mk2) and the rears did not come up on the web at all. Furthermore, in another portion of the same reference it was noted that Mazda RX7 inserts are at least 2" too long to fit. So this leaves a lot to be desired with certainty of them working. But I'll continue to see what additional information I can find for any of those vehicle applications.

Hopefully someone else remembers something about this?
 
In that last post I neglected to mention that I could only find complete strut assemblies listed for any Mitsubishi Lancers, not just inserts, and they do not appear to be that similar to the X's. And on the Koni website they do not list any part numbers for that Mitsubishi model except the generic race universal inserts (which happen to be much larger diameter than the X housings). So I'm certain the Lancer reference is entirely incorrect.

As for the RX7 application, the rears are not even struts, but regular shocks. So the rear Koni P/N given does not make sense here either. The fronts were once available as the Koni part number fererenced, but Koni no longer has any RX7 listings available. I did find some vague dimensions for the old listing and will compare it to the X's. It may at least help to confirm the comment about them being a couple inches too long. But it looks like a dead end anyway since they are NLA. Although KYB lists inserts for the RX7 fronts, those aren't any better than the currently available KYB strut assemblies for the X. But if it happens that front RX7 inserts will fit, perhaps another performance shock company has inserts available.
 
Hey Jeff, I am planning on modding the stock strut housings kind of like what was done here

https://xwebforums.com/forum/index.php?threads/bilstein-shock-installation.13174/

These bilstein shocks are designed for lowered cars, and I believe they will work with the old style struts that are not sealed. Hussein used the same shocks on his project. That said, I haven't crossed this river yet but it is the next major step on my build to set suspension heights to get measurements for the driveshafts to the Subaru WRX transaxle.
 
JimD said:
You can review this thread. Somebody using your name was in there discussing. :)

Sadly, there are dead picture links. Maybe Doug still has the pictures and can edit and repost? Doug?? You out there??
Click to expand...

Hey Jim. Yeah I'm still here. No, I dont have those missing pics. They were on a computer that is now dead. But....look at page 2 of the thread. Lots of pics still there.

Dr.Jeff said:
The earlier X1/9 suspension struts had a removable and replaceable insert or cartridge (the "shock" portion of the strut). At one time Koni offered inserts for them, but those are all long gone. KYB also offered some and that was back when KYB still used the high-pressure monotube design (aka Bilstein type), but they too are NLA. Seems like there were other choices also listed specifically for the X1/9 application as well, however like the rest of them you won't find any now.

I recall there had been a couple of options discovered involving the use of inserts from other makes/models. One that comes to mind was units for the old VW Rabbit. I never understood how that could possibly work as the Rabbit inserts are a couple of inches longer than the X1/9 ones (I have old Rabbits and compared them). Maybe someone knows how that was done. Or does anyone know what other inserts (for other vehicles) will work in the early style X1/9 struts? The goal would be something that is still available.

Thanks for any input.
Click to expand...

Some incorrect statements here. Firstly early X1/9s never came with inserts - they came with a removable and rebuildable "wet leg". Which basically used the inside of the strut housing as the outer tube of the shock. But yes, you could chuck all the innards and replace with a strut insert or cartridge. An easy and quick repair. Yes, Koni offered an insert back then - yes NLA today but old new stock does appear at times. Or used ones. Yes, KYB offered inserts too, but only as I recall in an oil version but perhaps also in a twin tube gas charged. Both meant as stock type replacement - not really a performance version. Never in a high pressure monotube De Carbon type design. Back then KYB NEVER offered inserts in a high pressure monotube design for any car - something about a patent thing.

Yes, back then there were plenty of options in X1/9 inserts - like Gabriel, Monroe, Boge, etc. Mostly just stock-type stuff. Yeah, tough to find these days, but old stock pops up on Ebay, etc. And no - Bilstein never made an X1/9 insert - or complete strut for that matter.

As for you stating that Rabbit inserts could not possibly work - well that statement is just wrong. Rabbit inserts ARE almost identical in length to an X1/9 insert. well within 1/8" or so. Yes, there are difference between Rabbit inserts and X1/9 inserts, but length is NOT one of them. I know you dont believe me - but check this thread:
https://xwebforums.com/forum/index.php?threads/bilstein-shock-installation.13174/
where Paul uses Bilstein Rabbit inserts in stock X1/9 early strut housings.
And there is a thread in the Wiki somewhere here about someone ( Ulix i think ? ) using KYB Rabbit inserts in early X1/9 strut housings.

Look at those two threads to see how it was done. And it can be !!!

BUT....I CAN tell you that most - Rabbit inserts CANNOT be used in an X1/9 strut. The reason is simple - Rabbits strut housings - although the same ( well within fractions ) length - were also bigger in diameter. As I recall (although it has been a while and my memory is a bit shaky) the X1/9 housings were something like 40mm ID and the Rabbit housings were 42mm ID. Thus most Rabbit inserts - like Koni, Boge, Gabriel, etc, that are made to fit snugly inside the Rabbit housing are too large in diameter to slip inside an X1/9 housing. Trust me, I tried...

One exception is Bilstein. For some strange reason the Bilstein Rabbit inserts - and there are several flavours ( sport, race, comfort, HD ) are all about 38mm OD and thus will slip easily into an X1/9 housing. Dunno why bilstein made them so small diameter. They even had to give you spacer rings to locate them centered in the VW housing. But yes, they ARE almost the perfect length for an X1/9 housing. And are still to this day readily available. But no, they are certainly not a direct-in to an X1/9 housing. Paul had to mess around with the gland nuts and make spacers, etc. He is obviously more clever than I am - not to mention wealthier (those Bilstein inserts are pricey ) LOL...

The other exception is the KYB Rabbit insert. Like the Bilstein, for some reason they too are small enough diameter to fit inside an X1/9 housing. But....legend has it they are valved weaker than a stock X1/9 shock. So really why bother....

There may well be other Rabbit inserts slender enough to slip into an X1/9 housing, but none that I am aware of....

As for other inserts from other cars that may work....well none that I have found !! I've poked around catalogs and gone through every insert we have in stock. Some internet chatter that early MR2 inserts would fit, but as far as I could tell, they are too long. Some sources suggest early RX7, but nope i checked. Late 80's Mazda 323 are pretty short, but good luck finding some performance options still around.

Generally, as time has gone on, cars have gotten bigger and heavier, and suspension travels have increased. And virtually nobody uses inserts any more - just all sealed struts. And Fiat used a very small diameter strut -smaller than almost anyone else. And really short on an X1/9 to make the car low. Going to make your search pretty tough. Yeah....maybe a 1972 Daihutsa Bongo used suitable inserts, but what good does that do you.....

Most importantly... most car manufactures worldwide stopped producing cars with serviceable ( ie ones that could take an insert ) struts by the mid 80's. and went with sealed struts instead.

Good luck.....
 
rx1900 said:
check this thread:
https://xwebforums.com/forum/index.php?threads/bilstein-shock-installation.13174/
where Paul uses Bilstein Rabbit inserts in stock X1/9 early strut housings.

.....
Click to expand...

An update on my Bilstein installation. Use of the sport shocks with stock springs gives a solid comfortable ride. The valving gives a sense of a stiff car. If I bounce on the bumper the car hardly moves at all. However, on the track the car still has a fair amount of body roll. It still gets around nicely though, and is competitive in the corners. The balance is good.

In reviewing the description, I see that I did not mention that I had to machine the top of the shock shafts. It was minor, and I cannot remember what I did those years ago.

Paul
 
Dr.Jeff said:
The earlier X1/9 suspension struts had a removable and replaceable insert or cartridge (the "shock" portion of the strut). At one time Koni offered inserts for them, but those are all long gone. KYB also offered some and that was back when KYB still used the high-pressure monotube design (aka Bilstein type), but they too are NLA. Seems like there were other choices also listed specifically for the X1/9 application as well, however like the rest of them you won't find any now.

I recall there had been a couple of options discovered involving the use of inserts from other makes/models. One that comes to mind was units for the old VW Rabbit. I never understood how that could possibly work as the Rabbit inserts are a couple of inches longer than the X1/9 ones (I have old Rabbits and compared them). Maybe someone knows how that was done. Or does anyone know what other inserts (for other vehicles) will work in the early style X1/9 struts? The goal would be something that is still available.

Thanks for any input.
Click to expand...
Actually, the earlier (at least 1974) cars did not use inserts. The strut housings were also the cylinder that a piston and rod moved in and they were filled with oil. At about 40K mine were totally shot. I bought a set of the KYB high pressure strut inserts and installed them after removing the stock guts. If you can find similarly sized inserts today it could work. There is probably some latitude in the exact dimensions as the KYB inserts didn't exactly fit like a glove either. I would imagine you would want something with a similar stroke length but the OD (as long as it fits inside) and overall length could be negotiable. I had to wrap the KYBs with bare #12 copper wire to keep them centered in the tube so there was definitely some slop to deal with.
 
Wow, lots of great input. Thanks to everyone.
A couple of thoughts after reviewing these posts....

I really appreciate the links to other related threads. I recalled some of it existed but as usual it seemed to elude me when searching. But others are ones I'd never seen, excellent.

Perhaps I was not clear in the definition of my interest with this subject.
First, I am only interested in finding possible inserts that will fit the stock X1/9 housings with removable internals (what I refer to as "inserts"). I have made custom or modified housings in the past but have no intention of doing it this time. For the same reason, some of the options presented are simply too involved with extensive modifications to make them work.
Second, I am interested in finding inserts that will allow me to lower the ride height (struts) considerably. So stock length inserts would be the longest I'd consider, and maybe not even that. Anything longer than stock will not work (for my needs).

So with that clarified, I can rule out a couple of the suggestions given.
I currently have a set of Bilstein Rabbit inserts. Today I measured them and the stock X housings, and they simply will not work. They are about 1.5" longer, both compressed and extended. If the housings were modified as was done by the others (e.g. reposition the lower mounts to compensate for the added length of the insert), and the shafts were modified (shortened to match the extended X length), then they could be used as a stock replacement (as the others did). But they do not allow the needed room for lowering or shortening...there would be almost no travel left. However from experience I know that Bilstein once offered a shorter version of their Rabbit struts. Commonly referred to as "Ultra Lows". I do not have the old part numbers handy, but possibly those are what some individuals used when they found them to be the same length as stock X's? They are in fact about 1.5" shorter than the standard Bilstein Rabbit model. If you could find a old set of the Ultra Lows then you will be competing with the VW guys for them, as they are highly sought after in that camp (with prices set accordingly). Otherwise the stock Rabbits are longer.

Regarding the previous reference to Mazda RX7 inserts. Based on the dimensions I found online for them, and the measurements I made of my housings, they very well might fit. The diameter is bigger than the stock internals but looks like it will still fit inside the housing. The compressed length is stated to be almost identical to the stock X units. But the extended length is about 2" longer (which could account for the report that they are 2" too long). So the shafts will need to be shortened to prevent overextension. The thing that concerns me is the length of the body itself. That dimension is not given online. And considering the extra extended length for the same compressed length, I'm guessing the body must be longer than the X housing. Frankly I'm not confident about the data given for them online. Without having them in hand it is difficult to say. And they are only for the fronts so the rears will need to be converted to use the same inserts as the fronts. Unfortunately Koni no longer produces them but given the popularity of the RX7 I'm guessing something decent could be found from other manufacturers.

I was once connected with the KYB US importer (back when they were introduced to America) and they did in fact make the monotube high-pressure design of inserts for some applications. But they were not a standard replacement listing.

Yet another interesting possibility. One of the current offerings in coilover units for the X has a replaceable insert that is very similar to the dimensions of the X housings. That item is available with a choice of inserts. Possibly one of those inserts could work in the X housing? Determining the part number for those inserts might be difficult though.

In general, it appears that at one time there were some possible options for using inserts from other applications in the X housings. I will continue to search.
 
One possibility may be KONI insert 8610-1343
image_29174.jpg
image_29176.jpg
One possability may be Koni 8610-1343 SPORT for the front of a 93-02 Mitsubishi Lancer/Mirage/Colt, they seem to be available still. Adjustable for rebound only, from the top. These are 39.2 OD, tapering out to 42.8 OD at the top, with 3 locating bumps 41.2 dia 46mm down from the top, so they will fit in an X1/9 housing that has the larger diameter near the top. Length is similar too at 527mm ext. overall. These bolt in from the bottom, so you have to drill a 12mm hole in the bottom of the X1/9 strut housing, the good news is that you don't need housings with replaceable inserts, you just cut the top of the strut off about 30mm from the top, drain the oil and pull the shaft out. The bolt in the bottom holds the insert in without the need for a locking collar at the top (there is a rubber sleeve provided to seal the top). The only problem is the ID of the X1/9 housing must be slightly larger than the lancer housing at the same point and the 3 location bumps are a loose fit, so you need to cut the housing at exactly the right distance from the top to locate firmly on the tapered part of the Koni insert. (Either that, or wrap some shim around the insert at the bumps to make it a tight fit). This is also complicated by the thin 50mm dia locking ring on the Koni insert, this needs to be above the top of the housing. In my case I had housings with removable inserts that I didn't want to cut up, so I ground that 50mm ring down to the insert OD of 42.8mm so it would fit inside the housing. The shaft diameter at the top, just below the thread is o.8 mm bigger than the X1/9 shaft, so you will need to enlarge the hole slightly in the top mount. And you may want to file some flats on the top of the thread, because the Konis have the flats on the 14.8mm section just below.
If you want to run with lowered springs, and keep the springs retained you would have to have the shaft shortened by the amount you are lowering it. You can gain an extra bit of length by cutting 10mm from the bottom of the Koni mounting point, and shorten the screw also so it doesn't bottom out in the hole. The Koni body is only 317mm long, compared to the X1/9 strut housing 340mm before cutting it. I have these inserts in the front of my X1/9 track car, with slightly stiffer than normal springs and are happy with them.
 
kmead said:
https://www.tirerack.com/suspension..._kwcid=AL!3756!3!76743398893!!!g!130303973053!
Click to expand...

Hey Karl. Just to be clear.....when I said that Bilstein Rabbit inserts could be persuaded to fit inside an early X1/9 strut housing, I was referring to their performance monotube inserts (which come in several versions ). I was not aware that Bilstein now offer a line of OE type twin tube inserts. - like the one you linked to. Whether or not that twin tube insert would fit I could not say. It would depend on the diameter of the insert. As I said, most Rabbit replacement inserts are too large in diameter to fit inside an early X housing. Caveat emptor on this one...
 
GregS said:
One possibility may be KONI insert 8610-1343
Click to expand...
Greg, thank you for this. Excellent detail work. I will have to look at it in closer detail to see for sure, but it appears to be a good candidate for my goals (a shorter insert to allow additional lowering). When I looked at Lancer applications previously I did not find this listing. I see you are in Australia and sometimes the availability and specific part numbers differ for the US market. So it might be more elusive here...or more likely I just missed it. I'll report what I find. ;)

EDIT: Just took a quick look at the specific Koni part number. In the US the listing is for a Dodge Colt, which is a related model. But that explains why my previous "Lancer" search did not get the result. Having the actual part number makes all the difference. And they do seem to be available here. Thanks again, I'll continue to research this option.
 
Jeff,
What do you mean exactly when you talk about length of the shock?
The body? The shaft?
The body needs to be short enough to fit inside the x1/9 tube.
The shaft short enough to not lose preload pn the spring when fully extended and even shorter when you use very low springs so that the piston is at a reasonable position within the cylinder.
The piston rod could be shortened, so mainly the length of the shock body is important, isn‘t it?
 
Ulix said:
What do you mean exactly when you talk about length of the shock?
Click to expand...
Actually this question might be the root of the conflicting views about some inserts fitting or not. The data online for the part numbers I was looking at only gave the collapsed and extended length, and diameter. Not the body length. And I totally agree, that is a critical dimension but I could not find it anywhere. So the total length is what I was mainly referring to (in addition to the diameter). As you say, it has a major role in the insert working with the particular springs, ride height, suspension travel, etc. So if the total length was not within a usable range - for my needs - then I ruled out that option. With the exception that I could shorten the end of the shaft if everything but the extended length was good. Obviously the less modifications needed the better, but I expect there will be some alterations required regardless. But just because a insert will fit into the strut housing does not mean it will "work". Especially for my particular definition of requirements.

That is one factor that I really like about the 'Dodge Colt' listing. Greg gives all of the needed dimensions and it is actually shorter than the stock unit, which is what I'd ideally like to find. I haven't had a chance to check out everything about it yet, but I'm considering making the hole in the bottom of the housing (for the insert's mounting bolt) big enough for the entire lower "post" (threaded projection or lug) to pass through. Then add a collar to the bottom of the housing for the mounting bolt to secure the insert to the housing. That would get the total length much shorter than stock...I'm looking at a ride height drop of at least 3" and still have some travel. My current set-up has very little travel (about 1.5") at that ride height. Which is the whole reason for this project with the inserts/early housings. ;)
 
Jeff, you can't have the entire 20mm post poking thru the bottom of the strut housing as it will interfere with suspension or drive shaft. Lowering 3 inches sounds pretty radical, have you looked into the adverse effects on suspension geometry?
Also, if you shorten the shaft you will want bump stops on it so the shoulder of the 20mm shaft can never go below the top seal in the strut insert.
 
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GregS said:
it will interfere with suspension or drive shaft
Click to expand...
Thanks Greg. I'll have to double check on the car, but previously I looked at the possibility of relocating the mounting plates for the bottom of the strut housing as a means of lowering the strut relative to the car (by raising the mounts). I recall there is some room to go below the stock strut before interfering with the suspension (front) and axle (rear), at least on my later 1500 X's. At the moment I'm not sure what the measurement was, but that would be how much the bottom of the Koni insert could protrude through the housing. Perhaps a combination of cutting 10mm of the lug and protruding them through the bottom, so only 10mm is below the housing. Even if not, the shorter length of the Koni, especially if the lower lug is shortened as you did, will go a long way to allowing the lower ride height I'm after. And yes it is low and does require other mods to make it work, but that has already been worked out. The biggest factor has been the lack of suspension travel at that ride height, with the existing struts. But these Koni inserts seems to be the answer.

I have no problem cutting my housings so these Koni inserts would be very easy to install. And I've already converted the housings to coilovers so the ride height can be lowered without having extremely short springs, plus helper "take up" springs are used. So I might not have to modify the shaft length (will have to see when everything is built). The only downside is the price of any Koni product isn't cheap.

I came across your previous post on the "T124" forum about this. At the bottom your links to the photos still work, so I was able to view the related pics. That also was very helpful. You did a great job of researching this and documenting your findings, thanks. These inserts are the only thing I've found that come even close to working, especially with a lowered setup.

By the way, somewhere on the "T124" forum discussions about VW Rabbit inserts for the X housings confirmed that the shorter versions were the model number being referred to when it was said they will fit. Basically there were three options for the Rabbit at one time; standard length (which is what I have, and is way too long), a shorter one (which is what others have been talking about), and a really short one. That third shortest one would be ideal for my needs however it has not been produced for a very long time. And even when it was, there were not many out there, with much fewer still remaining. So finding them will be extremely difficult and prohibitively costly.

Thanks again for sharing your info.
 
Ulix said:
a little less than an inch in the front
Click to expand...
That sounds about what I recall. And we are only talking about 20mm of the insert's mounting lug, minus any that is cut off, plus the head of the retaining bolt (so probably ~ 20mm / < 1" total). I also thought there was a little room at the rear, but really do not remember. The rear housings are a little longer to begin with, and with these inserts the top of the strut housing is cut off. Therefore the rears will already be shortened more than the fronts (using the same inserts for both front and rear). So even if there is no room below the rear struts that is fine, plus the front is always where the most lowering is needed.

I'm kind of surprised this mod has not been done more. The fact that any X strut housing can be used with them makes it a easy upgrade. Maybe the $150/each cost is an issue. But you are getting adjustable Koni's, with the ability to lower the ride height (especially in the front) while retaining plenty of travel. And these Koni's are rebuildable, which makes them a lifetime unit, and means they can easily be tuned if you want to make a custom suspension with really heavy springs, etc.
 
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