Well, in short, it looks like the 1985 Rear Upper Mount is not the same as the later years, so I can't weld a washer onto the mount plate and move it, I am not surprised really.
And to top it all off you can see that the mount hole is offset towards the edge of the frame (towards teh car center) and there is a rolled up edge there that prevents you from mounting anything flat on that edge.
It looks like I will have to weld up a mount bracket that replicates the factory mount,, then cut the factory mount off, and weld the new bracket on becasue I can't see how you can get into the boxed frame to put a nut on the mount bolts.
Spoke with QA1 tech today, their big issue with C4's and Coilovers is they say the mounting bracketsare flimsy,, well, I can take care of that, probably will use .250" thick CRS like I did on the front CO tower.
For you guys that have done this mod on later years,,,, do the pics look similar to the later years, except for the shock mount?
ALL PICS BELOW ARE OF THE PASS SIDE SHOCK
Here is a pic of the new spherical bearings that came today, this will help with the apparent misalignment on the shock loop.
You press out the Poly bushing, then press the bearing in and install a snap ring on the ID of the loop on both sides of the bearing. Part # QA1 EMB8-102pk
I cut the Towers off both sides. They are only @ .110" thick so we'll heli-arc weld .125" thick SS to the sides of each tower which will make them @ .245" thick,, then stick weld them back to the car hopefully tmorrow night.
Well, we welded 1/8 thick SS to the side of the stock mount, it ain't pretty, but its pretty strong, it was .105" thick before, now its .235" thick afte rthe SS was added
We also welded a larger base to the mount in an effort to spread out the load, the base is 1/4" thick 1018 CRS
RJ welding the mount on last night @ midnight
Welded on and moved forward 1.250"
Painted and since I kept the factory mount in an effort to make this reversible in the future,, I put a rubber bushing in between the Spherical bushing and the mount wall, I will search out a better solution for this but with teh tires on, you dont see it.
Nice thanks for the info. Do you think the 87 differs from the 85? Coilovers are my next mod after my LS swap. I've been intreested in this for some time now.
Nice thanks for the info. Do you think the 87 differs from the 85? Coilovers are my next mod after my LS swap. I've been intreested in this for some time now.
84-87 are the same,, for the rear is not a huge deal really, you cold bolt a U-bracket to the rear upper and be OK, and Ghoffman is making a rear lower that will replace the rear lower shaft that sticks out
Its the front that scare me, because the towers are so thin, they are only .105" thick and I cut mine off and used 1/4" thick CRS>
HOWEVER, Exotic Muscle makes a Bolt on kit with smaller OD springs that takes all of what I had to do out of the picture
But EM does not use QA1's which have 12-way adjustability for the shock action
Has anyone used the Guldstrand coilover setup? You guys have made me have to do this mod so now I have to try to research. What is the advantage to using QA1s or is there any?
The later are different. They have a flat plate. The top mounts similar to the front shock.
I see you used the QA1's springs..if by chance you dont like the spring try Hyperco. Their spring rates have better tolerances than most +/- 2% compaired to others at 10-15%. Good choice on QA1's.
I am doing a coilover on mine and just started making parts. I am putting the coilover where the org spring is and moving the rearend up a inch, changing the camber bar location along with the location of the toe bars.
My 85 is exactly as LD85's. The thing that made te biggest difference for the fit of my coilovers was making up a lower mount that moved the coilover body away from the knuckle. It completely did away with having to space out the coilover on the shock stud and eliminated the shock stud.
The thing that made te biggest difference for the fit of my coilovers was making up a lower mount that moved the coilover body away from the knuckle. .
You can set ride height at the desired height if the shocks are the rite lenght. Can change springs in a matter of mins. Most coilovers offer adjustable compression/rebound...some offer double adjustable on compression and rebound. Ride is so much better and performance is top notch. Corvettes should have come with them. When you get coilovers dailed in the tire stays glued to the road more than reg shocks and glass springs.
vetteoz, I made up a bracket that bolts in place of the shock stud. This allowed me to shift the coilover away from the knuckle. Without doing this you have to grind down the head of the mount bolt and even then you have to space the spring out to the end of the shock stud which i was never comfortable with. The only thing with the bracket is to fab up a way to keep it from rotating since it is only attached with a single bolt. I simply included tabs in the bottom that registered on the bottom of the knuckle. The total cost front and rear was the same or a litle less than the cost of replacement OEM springs. What you gain is significant adjustability both with the shock settings and the stiffness of the springs. QA1 springs are about $60 a set so it isn't that costly to have a couple sets around. Going QA1 is a lot more work because as LD85 said, the front spring housings on the 85 have to be replaced due to the size of the spring.
how does it ride compared to the stock set up?the reason i ask is because i read that one of the members on another forum runs 170#rears.but his car also looked like a dedicated drag car.and ill assume they run much softer spring rates for better weight transfer.
At this point i couldn't tell you. I'm still putting things together with the engine and haven't had it on the road for much more than around the block trips
FWIW, I am going to put 325's on my rear, it's a little too soft for me.
c-4lhozwalte ,, I can not imagine 170's on the rear unless it is a dedicated drag car, you could stiffen the shocks if you have QA1 adjustable, but IMO the car would bottom out constantly.
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