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Strut insulator question?


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I understand some people have gone from the strut insulator to a mono ball setup. Does this lower the car at all? Is it useable with the stock spring setup vs coilovers? I did something similar years ago on my 510, where I removed the rubber and using a steel plate moved the bearing cup against the bolts. Lowering the car significantly and it made the steering easier and more precise. So I guess I am also wondering if anyone has done this and what the effects were :shock: ??? Thanks!!!

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Hey Joe,

I made some non-ajustable offset camber plates out of some 1/8 inch steel.

It eliminated the rubber shock mounts and lowered the car WITHOUT messing with supension geometry(other than camber which I ajust with ajustable camber bushings).

 

I do not recommend using ajustable shocks with this kind of setup due to the shafts not being solid. I have been told stories of shock shafts breaking.

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Joe,

I`m going to say 1.5".(the thickness of the stock insulators)

I had some other modified insulators on before these(which also lowered the car)so I did not take a measurment.

I dont have any pics at this time, but I`m going to be doing some suspension work shortly and will document these an other mods.

 

I used 1/8 plate 3.5 OD, used a holesaw to open center of the plate.

I burned a regular shock insulator to get the center core out(part that the strut shaft mounts to with the D shaped whole), then welded the two pieces.

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  • 3 years later...

New life into an older thread!

 

I'm very interested in this. I know that to keep the suspension from self destructing, some form of flex has to be built into the upper section of the strut assembly.

 

I want to upgrade my suspension, but I don't want to go all out at this point because my 280z is just my daily driver.

 

I was planning on getting AZ z car springs (don't lower too much, but very stiff) and Illuminas, but from what I've seen this won't lower the car very much.

 

I was wondering how to somehow eliminate or modify the upper insulators to reduce the size of them, but still keep some of the insulating/flex qualities using a monoball setup or something similer.

 

At this point (as a poor student) I'm not in the budget for EMI camber plates, nor similer bolt-in equlivelents. I was simply trying to figure out a way to lower the car by taking advantage of the parts which seem to alow me to do so: the large strut insulators.

 

Would you reccomend picking up a set of OEM insulators and modifying them to make them shorter? Or starting from scratch and fabricating some sort of monoball insulator eliminator?

 

Thanks!

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The isolators are two peices of metal with rubber vulcanized inbetween them. You can't make them shorter. However, if you were to burn out the rubber, weld the two pieces of metal together, then figure out a way to mount a monoball in there, you might be able to lower your ride height by at least 1/2" or so. Not much.

 

EDIT: If you were to mount the monoball on top of the isolator, that would drop it even more.

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I found this thread http://forums.hybridz.org/showthread.php?t=96762&highlight=strut+isolator

and I want to do the same thing. I guess the only difference between the front and rear upper assemblies is the bearing in the front needed for smooth steering action, while the rear simply has a spacer.

 

I wonder if there would be some way to modify this while still using the stock (or a modified) OEM spring perch...

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I read somewhere on another site a while back that the stock mounts can be modified by heating the mount and removing/modifying the center section and then reinstalling. No pictures were included so I don't know if this is possible.

 

This is an option I'm considering but I have yet to hear if someone has tried these:

 

http://www.thezstore.com/page/TZS/CTGY/PSDC08

 

They are supposed to lower post 74 Z's by 3/4", are used with stock springs, and you get some camber adjustment.

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Polyurethane is a bad choice of material for this part. The insulator doesn't just insulate road noise from the chassis. It also allows the strut angle to change when the suspension goes through its travel. If you use poly, that's a much stiffer material that doesn't want to flex to let the strut move. What's worse, there is less of it. This would put a lot of side load onto the strut shaft, which would wear struts out quickly and cause failures, not to mention it would add a ton of stiction to the strut. It's an all around bad idea.

 

This is kind of like the poly TC bushings. The poly has to flex in order for the suspension to move. Side load on the TC rods has caused them to snap off, as has been discussed here: http://forums.hybridz.org/showthread.php?t=87758

 

If you want to get rid of the insulator get a camber plate or make a monoball plate like Tom Holt did: http://sth2.com/Z-car/shocks.htm. I'd just go with the camber plate. It also holds the monoball, but you get the added adjustment as well.

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The whole idea behind this mod I think, is to keep suspension travel while eliminating the large size of the insulator. In order to do this, you cannot move the upper spring perch upward, because with the load of the car on it, this would in fact reduce suspension travel!

 

So you have to keep the upper spring perch in the same location or lower, and by lowering the spring perch you move the tip of the strut shaft upward, which won't work because the top is threaded only so much, and you still need to get that upper retaining nut on it to keep the assembly together.

 

The only other solution I could figure was this: Let's take the front end as the example. Pry off those plastic strut hole caps and look in. The retaining nut is recessed into that hole. If you could shorten the insulator so that the retaining nut came out of the hole and was flush with the 3 strut assembly bolts, you'd lower the car by that much without affecting anything else!

 

Only problem is: I measured this distance, its a whimpy 20mm. Any more and you'd have to drill a hole in your hood bracing for the tip of the strut to go into when you close the hood. But for the rear it should work, there's no hood to hit there, it would just protrude into the interior.

 

Sorry if this is a little vauge to understand...

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The whole idea behind this mod I think, is to keep suspension travel while eliminating the large size of the insulator. In order to do this, you cannot move the upper spring perch upward, because with the load of the car on it, this would in fact reduce suspension travel!

 

The spring length stays the same, so everything else being equal, the shock is going to be compressed the same. What in fact you are doing by decreasing the height of the insulator, is you are lowering the body in relation to the suspension.

 

If you take a front insulator and move it to the back (on a post 74 Z) you will drop the rear body about an inch. If you measure the available travel of the shock before and after you will see that it remains the same with no loss in travel.

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The spring length stays the same' date=' so everything else being equal, the shock is going to be compressed the same. What in fact you are doing by decreasing the height of the insulator, is you are lowering the body in relation to the suspension.

 

If you take a front insulator and move it to the back (on a post 74 Z) you will drop the rear body about an inch. If you measure the available travel of the shock before and after you will see that it remains the same with no loss in travel.[/quote']

 

You're correct. I mentioned moving the spring perch because usually aftermarket springs are much shorter than OEM ones. But with the use of OEM parts, you're absolutely correct.

 

Infact, the way Nissan made the insulator on 280z's larger was simply by making the top larger, making a deeper recess where the large center nut resided. If there were some way to make the insulator small enough to the point where the center nut was moved up (by decreasing the size of this recess to zero) you would lower the car even more. Of course this amount is limited (to about 20mm as stated in my last post) in the front by the hood bracing, damn.

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