ls six

I figured I would use my old strut mounts to fabricate solid upper mounts, looking up what others have done and what the aftermarket and OE's have done it looks like everyone has used bearings for the mount/strut shaft interface.

On most struts (like my Mazda) there is a bearing between the spring and upper perch to allow smooth steering without spring popping noises but the strut shaft is bolted solid to the mount, the shaft rotates in the strut housing freely so this isnt a problem.

My Mazda came with squishy rubber filled mounts much like the 3rd gens and I replaced them with ones from a protege that are much stiffer, they simply have a small amount of rubber around the middle plate (where the strut rod attaches) held between two plates that bolt to the strut tower.



My question is dose anyone see any problem with me gutting my mounts and welding a plate inside the housing? A spacer, some washers and small bushings (think about the upper shock bushings used for the rear on our cars and countless others) would allow the shaft to move around as the suspension cycles and absorb a little noise and vibration.

gregsz-28

iTrader: (1)

If you want to use bushings, why not just use the stock mounts the way they are?

JamesC

iTrader: (5)

I'm using Spohn's version. I've not noticed an increase of noise and/or vibration.

JamesC

gregsz-28

iTrader: (1)

+1

ls six

Theres bound to be a huge difference between 20 year old stock rubber and brand new thane shock bushinge that are proabably less than a tenth of the size, they would only be there because the strut would need to move slightly with the LCA.

83 Crossfire TA

iTrader: (2)

Huh... interesting question, and I suspect that most people won't see what you're getting at or why... I also suspect that unless you find someone that knows about how the insides of the front struts are built you're not going to get a real useful answer.

My instinct is that they are probably designed similar macpherson struts used in a standard strut suspension where the strut body pivots on the strut piston and shaft seal area. I don't know if shocks, rear strut assemblies and struts used in modified macpherson strut setups like our cars use a different internal design or not. If they are the same then your setup would be a simple, cheap and more durable way to get a more responsive setup, just give it enough give to compensate for the slight angle changes with suspension action and make it totally rigid past that. In reality, if the internal design is the same this would increase the durability of the struts by not always wearing at exactly the same point, OTOH, if the piston and shaft seals aren't designed to tolerate rotational motion you're likely to destroy them quickly.

Do you have one of each type to cut apart and compare them?

ls six

Thankyou cross! I was afraind the whole time I wrote the original post the thread would be nothing but me trying to make my thoughts clear to a bunch of hostile responders lol.

Thats exactly what I was thinking, I might stash a strut or two from the shop and disect it along with one of my junkers to see but I really cant see there being an issue.

I mean struts, even ones like ours are designed not only to resist linier motion like normal shocks but they must resist significant loads from the sides because it needs to locate the wheel like a control arm would.

I would think this would require much more surface area aside from the seal it's self between the rod/piston and the housing than a shock.

The piston and tube are still round and everything will ofcourse be very well lubed so i cant imagine what would be dammaged unless the piston and rod seals are really designed to not seal well when being rotated.

I'll try it with the junk struts first to spare any high dollar parts and let everyone know what's up.

I'm also wondering if the bearings even rotate freely as the car sits now, inorder for it to spin the resistance of the strut rod to spinning would have to be greater than the resistance of the upper mount bearing. I'll check mine this morning.

83 Crossfire TA

iTrader: (2)

I used to work at a speed shop and did some checking about this. I was hoping to come up with some names but didn't, but did come up with who to try. I didn't have time to make the calls (sorry, real job now ) but if you get to it before me I'd appreciate if you post what you learn (I've had similar thoughts about this, just haven't had time to pursue it lately). Places I would try:

- Edelbrock- if you call the support number for the IAS shocks and ask around you used to be able to get through to one of the engineers there, I know that the shop had some luck with this with finding information about using one of their PN's in what wasn't an intended application. they were actually designed in house.

- Koni- they have a rebuild service, check with them

- there's a couple of companies that will rebuild/revalve many performance shocks out there, 4th gen guys used to run custom valved bilstines all the time, same deal with Konis... I didn't get a chance to do any digging for #'s.

laiky

I've wondered about this my self, most mechanics carelessly spin the shafts when installing but i never saw a failure. The deflection of the shaft is the problem (I think)

ls six

I think you brought another point to mind crossfire, I'll likely be doing koni's or bilsteins anyway since I dont really wana skimp on shocks/struts on this caw when it can easily bite me in the *** if I get it wrong.

I used some adjustable KYB's on the mazda and they have a good rep in the mazda world but they seem to be considered just average in the 3rd gen world so i'll swing with popular opinion this time.

But yeah, with konis/bilsteins or any aftermarket strut really I shouldnt be concerned with what the OE,s intended.

Infact it seems likely that the aftermarket suppliers would be using hardware designed for the 99% of typical coilover struts in 3rd gen struts just because it's available and not especialy cost effective to design a strut that's NOT able to rotate freely.

Manufacturers typicaly will use their own parts assembled to fit the app at hand rather than trying to mimic the factory to the last detail.


EDIT: I did go ahead and look at the strut rods while cranking the wheel back and forth and the bearings definitely rotate along with the strut rods and housings.

ls six

Got a response from Koni today...

Heres my email.


And heres the response.

Quote:

Shouldn't be, but they are made in use w/oe mounting.

Paul McLaughlin
Koni Shock Absorbers
ITT Corporation
Racing Technical Sales Rep.
1961A International Way
Hebron, Ky. 41048
800-922-2616 option 6

racer7x

iTrader: (1)

My thought is that it will be fine just driving down the road but you may find some bind in your steering under high wheel load situations, as in braking and/or hard cornering.
May also induce accelerated wear of internal strut parts?
Just thinking out loud....

6speedIROC

iTrader: (3)

The strut rod wil rotate no problem in the housing, you won't hurt anything...but racer7x is right in that when steering, you'll notice higher effort due to the internal friction for rotation vs the spinning of the bearing. The bending moment on the stuts is very large!

ls six

Thanks for the input, I'll compare the resistance of a 3rd gen strut to what I know a typical strut feels like then make my decision.

JeremyNYR

iTrader: (2)

Does anyone else find it rude when you go through the trouble of thoroughly describing your situation only to get a one sentence reply? It makes me wonder if the person read what I wrote, understood it and knows what the hell they're talking about when just giving what amounts to just a yes or no answer. In this case it was even worse, it was more like "i think it's okay". You can't tell if they thought it out or if their response might as well be followed by "durrr"

83 Crossfire TA

iTrader: (2)

Yea, I'm with you, that answer basically amounts to a guess and a cop out in to cover his *** if he's wrong. Nothing useful and too damned lazy to go and talk to someone with a clue and get the right answer.

BS like that is often enough for me to say **** them and find another source of parts or whatever it is that I'm doing at the time. Too bad that in this case there isn't really any competition at the same level.

ls six

Lol, I didnt take offense at the response, infact I'm supprised I got one at all. Or that it didnt include the person pimping some other part as a solution.

I'll give it a shot and let the world know whats up after a while, with GM's hyper boosted steering in place I dont expect much in the way of resistance, the major issue that I'm hung up on is potential dammage to the strut seals. Like the man in the email said "shouldnt be" but I dont claim to know all and there very well could be something I dont know here.

85TransAm406

iTrader: (1)

I guess it would depend on the construction of the strut internally. I would think different brands/product lines might be designed differently. For instance, the rear shock on 3rd/4th gen Koni yellows is adjusted by turning the shaft, so it spinning it while driving would be bad. I know the fronts on most others aren't adjusted this way, but just an example of how it could be bad without knowing the inner construction.

Primetime91

iTrader: (15)

Did you ever end up doing this, or still plan to?

Just thinking out loud right now, but is there any reason the stock rubber couldn't be replaced with polyurethane, to do pretty much what you'rer describing? I.E. just enough "give" to compensate for the change in angle as it moves with the control arm. Obviously not practical now since no company makes them, but seems like it would be an affordable alternative to aftermarket solid mounts?