Commadore shocks in Sigma Struts

[DanTurboLancer]

As it says im looking at putting the Commadore front shocks into the Sigma struts.

Can someone give me some ideas on this, or direct me to an existing thread that gives a good discription of this??

[A112H]

I don't know if my case was normal or if I was just lucky buy,
I bought my GH struts coil over modded (don't know if they were shortened or not)
Bought some Monroe sensortrac inserts to suit VB-P
Slipped the inserts in and had to use the new retaining nut as the Commodore inserts are rounder and the old nut wouldn't fit over them
Had to drill out the coilover top plate to suit the shaft diameter as this was left small so I could match it to any insert I chose to use
Slipped the spring on, top plate, stock GC strut tops used the new nylock that came with the inserts, job done.
That is it, all pretty straight forward and even the retaining nut treads are the same

[DanTurboLancer]

Hmmm well mine are alittle different...

Id better check, but i dont think the shocks that came in the Purple Lancer struts are factory Sigma...??

They are Longer in the Shock body, aswell as longer in the shaft.
however they still had some spacers in the bottom of the strut...

Ill get the numbers of the shocks and chase that up.




Ok the problems im facing.

Yes the Commodore struts fit no problem.
But if i use the Sigma threaded shock retainer, there is play at the top, which means the strut can lay over abit,
which means that the shock rod leans against the Inside Diameter of the retainer, and will rub.

If i use the Commodore Shock retainer, which as you said, does screw into the Sigma Strut,
There is a couple of mm gap between the top of the shock and the retainer when fully screwed down...
So i would just use the spacers that were already in the bottom of the struts to lift the shocks...
Except i am trying to get the shocks as low as i can in the struts.. Even the 5mm will really mean stuff all.



The biggest problem im looking at at the moment, if the Strut top bearing is 15mm Inside diameter (Which suited the old shocks)
But the Commodore Strut is 14mm where it is located in that bearing.
So i have a half a mm play around it.

I am going to over come that by machining a shim.


Then the other problem is as you said the Spring top retaining plate does not fit over the shaft, so i will have to drill the hole out.

What i am wondering is,
the old shock has a flat section, as does the Spring retaining plate.
I am to believe that is to hold the retaing plate and stop it, and the spring from being able to spin.

So if i simply drill out the Retaining plate hole, will that cause an issue with the springs spinning and will that upset the suspension?

[C_Fernance]

I looked at this the other day as one of the inserts died in the Sigma. I'm running GH Scorp struts in it. Have some Commodore insert so decided to try and fit them.

The Commodore strut body is about 5mm longer, but the retaining nut still had plenty of thread to hold it in. Overall length is about 20mm shorter though. The Sigma top plate won't fit without mods though. The spring plate has a flat in it so it won't go over the Commodore insert as it doesn't have the matching flat machined on it like sigma inserts. The insert also has a smaller diameter top section so it could move around a couple of mm inside the Sigma strut top.

Easiest way i can see to fix it is to drill/file out the hole in the top spring plate so it is round, then have a sleeve made up that slips over the top of the insert and prevents it moving around in the top spring plate/strut top.

Edit: You pretty much figured out the same as what i have.

[DanTurboLancer]

Thanks Chris,
Good to hear that you have come to the same conclusions!
Check with that shock retaining nut (That screws in the top of the Strut)
If it holds the shock centred,
Mine doesnt have a Radius inside the nut that locates the shock in the centre,
and as i said it allows play, so the shock can move and the shaft will rub.


To stop the Spring top plate from spinning,
i was thinking of milling a keyway into the shock, and then filing the plate to suit the key...
Or machine a collar that will slip down onto the shaft and be held in place with Grub screws.
then have a bolt or pin up through the Spring plate...

Any other ideas anyone??

[Rally_2.6LC]

Like Galant_GTO said VB-VP shocks and ive been told a 20mm spacer at the bottom (washers or 20c pieces, or build a propper spacer on a lathe).
Not sure about height with the coil overs etc, but I know the shocks fit as thats what all the rally guys use in their lancers.


Cheers Matt

[mbrallying]

I didn't have to put spacers in mine they were the perfect length. I used gh sigma struts with coilover kits and commodore bilsteins. The only thing I had to do was make a sleeve for the bottom of the shock as the commodore legs have a taper at the bottom and the sigma ones don't. Just made it out of some exhaust tube and it was a perfect fit.
The 14mm shaft was right for the tops aswell.

[FUKRTA]

I MODIFIED VS COMMODORE COIL OVERS TO SUIT MY GE SIGMA