OK so I measured 26 1/8" between the shock towers, on the flange where the shims rest. Clearly I'm 1/4" short of the desired mark. No cracks noted. Can I assume this is within range of the spreader bar solution, and would there be any local stress relief benefits to loosening the poly engine mounts during the "spreading"?

 

Did you order the SpeedDirect spreader bar whether direct or from Ecklers or other retailer? If so it is not meant to push the towers back to OEM position but to stop them from flexing in. There are a few excellent threads on this bar. I will be installing mine as soon as it warms up. Will taise the wheels up just off the ground install brackets and tighten bar by hand, lower and tighten maybe 1 turn.

https://www.corvetteforum.com/forums...justments.html

 

Thanks, I did read that thread before. It's a Sharkbite aluminum bar. I doubt it will want much preload either.

Steve

 

Yup, that's it. Mine is in the garage, when it arrives you'll see what I mean in that it is not meant to move the towers back into their original position if they've fatigued a bit.

 

it just prevents flexing, but they do a fantastic job. you will be pleased.

 

As GDH said, raise the side of the car to take the stess of the control arm.
Remove the nut (13/16" IIRC) put the mount on andr tighten up the nuts just enough to allow final "front/rear adjustment" of the mount.

Bolt in the bar on one side keeping in mind that each bar end should have a similar "range of adjustment" (ie dont bottom out one end of the bar and leave all the adjustment for the other end).

Get both ends mounted and turn the bar by hand until you cannot turn it any further. Slide the control arm mounts back and forth until the fan and shroud clear the bar. You may need a spacer for the mechanical fan (details in the other spreader bar thread). once the bar is aligned correctly tighten down the mounts and give the bar another 1/2 or 3/4 turn (preload). The manufactures instructions should give you an example of reasonable preload. You want it snug, not "pushing out" to attain a desired measurement.

On my '78 (mechanical fan) the control arm nuts were a bear to get tight. Air tools wouldnt fit, I ended up using a ratchet and a swivel and a couple extensions.

In a couple posts I read some people used a beefier bolt for where the bar mounts to the control arm bracket. I used the supplied bolts with no issues. Once it was in and tight I backed off the little nut and added a drop or two of loctite for the h3ll of it. Might not be needed with a nylock nut, but I did it anyway.

good luck.

dodosmike


EDIT: https://www.corvetteforum.com/forums...clearance.html

 

Thank you guys for these answers. Yes I could have waited for the install instructions to arrive with the bar, but the project is a complex series of interwoven systems and it helps me to learn everything as early as possible.

 

I have the instructions in front of me an nowhere do they mention that you should raise the wheels off the ground. Learned that one on this forum - makes sense just not sure why they didn't include that part.

 

It was quite a while ago that I installed a spreader bar, but IIRC if the wheel is off the ground the trailing arm mount will work its way off the studs as you loosen the nuts. With weight on the suspension you can loosen the nuts to install the spreader bar without anything moving.

Like I said, it's been a while since I did the install so I could be ***-backwards. I would try loosening the trailing arm nuts with the car sitting on the ground. If the upper control arm bar doesn't move then you are all set. If it does move raise the wheel and see if the upper bar slides back into place.



Rick B.

 

Trailing arm? Im not following. Maybe just the terminology.
Control arm maybe? I didn't have any issues with the control arm bushings moving at all.

dodosmike

 

Sorry. Meant to say Control Arm. The control arm shaft will start working it's way off the studs as the nuts are loosened if the car configuration is wrong. It's probably easiest to try loosening the control arm nuts a little while the car is sitting on the ground. If the shaft stays put you can go ahead and remove the nuts. If the shaft stays pressed against the nuts as they are loosened, tighten the nuts up, jack the wheel up and try again. You don't want the shaft loosening up because then alignment shims fall out and that makes a real mess.

See how many times I said control arm?



Rick B.

 

Spreader bar for the 68 from Dick Guildstrand. Guildstrand's Motor Sports.

 

I have had my speedirect spreader bar on my 78 L-82 4speed with Stock mechanical fan for several years now and had to remove and reinstall more than once last Spring 2014 again during the rebuild of the motor. I too have/had no instructions but figured out the best way to get the bar to fit on the initial install was to jack up one side to relieve the tension on the control arm to get the spreader bar in. Besides Poly upper and lower control arm bushings, one of the best and certainly one of the easiest ways to improve the handling, ride, and steering of a C3 for the money…I have Bilstein Hd shocks, the Spreader bar, poly upper and lower control arm bushings, a custom blueprinted/rebuilt OEM Steering box by Gary R, and 255/45/17 ZR tires-holy smokes…completely different feel from the gymkhana OEM front suspension...

 

Besides Poly upper and lower control arm bushings, one of the best and certainly one of the easiest ways to improve the handling, ride, and steering of a C3 for the money…I have Bilstein Hd shocks, the Spreader bar, poly upper and lower control arm bushings, a custom blueprinted/rebuilt OEM Steering box by Gary R, and 255/45/17 ZR tires-holy smokes…completely different feel from the gymkhana OEM front suspension...[/QUOTE]

Well thank you....you must be one of the bad influences in CF that have inspired my Spring 2015 selection. I've started taking arrival of the Bilstein HDs, spreader bar, poly sway bar bushings, 245/45/18 Coys with Potenza RE-11s, solid heim camber arms, and 8" rear spring bolts.

Now if it ever quits raining here, I can get some work done!

 

so which is the best spreader bar to get, is there a complete bolt in kit, thanks mine a small block.

 

Best? Define best. Engineered? Quality? Price? Availability? Ease of installation?

There are a few manufacturers. I bought a speed direct bar, bolt it, spun aluminum, decent mounts. Seems like decent quality to me. Was less than $100. Last summer.

I think most parts retailers carry them.

Dodosmike

 

Is there a group purchase going on? I want in on it if so....

 

I don't think that there is much to choose from from either of the 2 main vendors, VB&P or Speed Direct.
http://www.vbandp.com/auto-parts.htm...category_id=47

http://www.speeddirect.com/index.php...3-spreader-bar

 

These are the two vendors I am aware of that offer spreaders bars for C3's-I have had both…

The VBP bar is much better suited to C3's WITHOUT the stock mechanical fan-aftermarket electric fans-since the tabs for the control arms have to welded in the correct position by the user, for placement of the actual bar. The VBP bar is much beefier and heavier than the speedirect bar and I could never get mine to fit with the stock mechanical fan with proper clearance between the fan, pulleys, and water pump, plus the additional welding was a going to be a pain. Sold it to a forum member for 50$.

I currently have the speedirect aluminum bar that has pre welded tabs for C3's with mechanical fan. It is a smaller diameter bar and fits perfectly in the tight space…close by no issues in 4 years now and it works great eliminating frame flex. I would highly recommend this spreader bar for C3's with a stock mechanical fan.

 

Same for me, the SD bar has 1/4" to 1/8" between the mechanical fan blade and the shroud on my '78. 100% bolt in, no welding.

dodosmike