LD85

I am about to install coilovers on my 85 and someone mentioned that the 84-87 shock towers can crack or people have had them crack at the welds.

Anyone with experience that has coilovers on their 84-87?

0Vector Vette

I have coil overs on my 89 frame. I ran some support rails from the top of the shock tower to the frame. Only makes sense, the original design isn't supporting the whole weight of the car, now it is.

LD85

Many thanks, I hate to bug you but could you send or post a pic please?

BrianCunningham

I'd run a camber brace as well.

LD85

No problem, seems like an easy install from its appearance and they seem to be reasonably priced

Also, I will add some weld to the vertical mount sides,, and add some 1/4" thick CRS to the tower for support.

Right after I finish pulling the engine and putting he new crank in!

LD85

Anybody got pics of their supports?

Zip Corvettes

89 shock towers are different than an 84-87. Coils will not fit the earlier towers without cutting which will weaken an already weak shock tower. You will need to buy a set of 88-96 shock towers and then reinforce them and you will be fine. you have to remeber even the 88-96 towers were never designed to handle the entire weight of the car which is what they are doing with coilovers. You should be fine in the rear as long as the shocks you are buying are for an 85. The 85-87 uses a bracket with a bolt that goes through it instead of a bracket that bolts to the frame.
Justin A.

LD85

Awesome, I plan on cutting ht towers and welding side an top supports using 1/8 or 3/16" (or 1/4 if necessary ) thick CRS.


I did not realize that the 88-96 towers should be reinforced also.

BrianCunningham

Some vendors use a shorter spring and a spacer
early

late

LD85

OK, someone needs to make this a sticky.

1985 Shock Towers are too narrow for the QA1 coil spring to fit into the tower, even with cutting and "flaring" the towers outward, the back of the coil spring shock hits the tower.

Options are;
1. Cut the top off of the Tower and weld a new top onto the tower after flaring the towers outward, and also, move the stud mount hole away from the engine by 1/2" ,,, then weld vertical supports to the outside of the tower,, my concern is that this will change the angle of the shock and make it become more vertical by @ 5-7 degrees

2. Cut the Towers off and weld on 1989-1996 Shock towers, but from what I understand, they need to have reinforcements welded onto them too.

The only way coilovers will work with the stock tower, (IMHO) is to have a smaller diameter spring such as an Exotic Muscle's Coilover , which is 2-7/8" OD according to EM.

Too be continued.....................

BrianCunningham

Where are you getting this information?

Did you read my last post?

LD85

[QUOTE=BrianCunningham;1559851412]Where are you getting this information?

Did you read my last post?[/QUOTE}

Thanks for the info but,,,,

I have my car apart and I am relaying what I see, I have already cut my tower and ,,,,a smaller spring diameter and a shorter spring "might" barely clear, I figure that a 1/2" gap fromthe tower to the spring would be ideal so the spring overall diameter would need to be smaller by 1.0" OA, and to do it right, the options I listed are what I see to be possible solutions.

No offense but have you put CO's on an 85? I cant find anyone that seems to have done this so far.

NUckINg FuTS

I have the EM coilovers on my '86. Had to flare out the towers a bit. Everything fits fine. No problems as of yet. Here's a pic of the modification done to the towers. (No extra supports added).

LD85

Wow, so it appears that the QA1 Coil diameters must be way too large, I know that the EM's re 2-7/8" diameter from what Merle told me.

LD85

Since the 1985 shock towers are wimpy and narrow, I cut them as seen in the pic below.

Then I machined some 1/4" thick 1018 CRS to match the same angles as the stock towers and ol'RJ welded them up.

The last pic is just the mock up of the new QA1 in the new tower.

We will weld the towers on tomorrow and i will post some new pics in a few days, once the wheel well area is cleaned and repainted,.





welded on, will wire brush and paint this week

Zip Corvettes

That looks good, but you may have one small problem. When you are welding 1/4" to 2/32" you have a problem with weld cracking. What I mean by this is it take allot of heat to penetrate the 1/4, but that amount of heat can thin the 2/32 to where it can cause a crack on the edge of a weld. You might want to TIG this bracket in instead of MIG welding it. An alternative is like I stated before, use the 88-96 bracket and just reinforce it. It you are set on using those 1/4" brackets then why don't you C channel it so you have some of the bracke actually go under the frame. You will get a ton of support from it like that. Also when they go to weld the heat of the weld needs to be concentrated on the 1/4 and let it fill or melt into the frame, that way you don't have to worry about thining the frame and the weld still penetrates.

LD85

We already welded to the existing 1/8 thick brace on the top and onto the existing 1/8" pieces of old shock tower and the frame which were spot welded to the frame.

No doubt there was heat but we welded to the old brackets that were attached to the frame already.

I hope its not an issue, we'll see.

I had hoped to get some pics or ideas from others but no one offered up any pics.

VanSpeed

Thanks for posting this picture of your front coil over install on an early C4. A question for you, did you have to relocate your front sway bar forward any so the end links clear the coilovers ? I have seen that this was needed on front coilover conversions for the later C4 and can not tell from you picture if it was necessary on with the EM conversion.

Thanks,

Brian

BrianCunningham

Nice mod LD85

LD85

Thanks BC, the good part is that I could always go back to stock if desired