Project Scope Creep - '74 Nova Spirit of America

[cornfedbill]

This is how the control arm sits relative to the bump stop at the desired ride height. As you can see, the bump stop is contacting the frame. I will be modifying the outer loop of the spring bucket and bump stop on the frame.

I am debating replacing the rubber bumper on the control arm with an OEM part so it has a progressive rate. I will just have to move the frame mounted stop more to compensate.

Any thoughts?

[cornfedbill]

I removed the bump stop from the frame and trimmed the frame around the spring pocket so the control arms can move through the full jounce freely. I will need to brace the frame where I trimmed it.



The 9-1/2 inch spring fits well. It will need a spacer to get the ride height correct. It is about one inch low. The adjustable AFCO spring spacers will need some modification to work properly. I think I will need to modify the upper spring seat also so everything will fit and sit squarely.

[cornfedbill]

Here is a photo of how I clearanced lower control arms. They look pretty stock still. I did not remove very much, only about 3/8 inch. I think it will work well. Now the control arms can droop fully with no contact with the crossmember until well beyond the normal range. I will now be able to lower the control arms enough to comfortably install the springs and adjusters.

[cornfedbill]

More work today. I put the driver side bump stop on the frame after trimming the spring bucket for clearance. The rubber stop will hit at 3" jounce, just where I wanted it. It's just roughed in right now. I need to finish welding and bracing it all. But it is progress.

[cornfedbill]

More work tonight. The driver side is almost complete. It looks pretty good. The bump stop is so low it is lower than the spring bucket, as can be seen in the pictures. The outside of the bucket has been lowered quite a bit also.

I am getting eager to assemble the suspension and check for tire clearance.

[Zanie]

Hey Bill,
Very ambitious and cool project, my brother had a hatch when I was a kid...only for a little while before it was totaled parked right in front of our house.

OK, I get the lower control arm pick up point move being the Gulstrand mod......the hard way! I understand the subframe mount moves down to move the subframe up into the car, but what about the mounts moving back? what's going on with that?

[cornfedbill]

Hey Bill,Very ambitious and cool project, my brother had a hatch when I was a kid...only for a little while before it was totaled parked right in front of our house.OK, I get the lower control arm pick up point move being the Gulstrand mod......the hard way! I understand the subframe mount moves down to move the subframe up into the car, but what about the mounts moving back? what's going on with that?

Dan,Sorry for the delayed reply. Moving the mounts 2 inches rearward changes the center of mass rearward about 1 percent. That is not much, but every bit counts. It also gives me more clearance for big tires in the front. As the tire turns outward, it gets closer to the firewall. This will eliminate that clearance problem.

[cornfedbill]

I finally got back to this project this week. I have been buried all summer with other stuff.

I finished the passenger side bump stop and spring bucket. I need to weld he seams on the bottom of the frame before I flip it over and move the upper shock mount upwards so I do not bottom out the shocks before I hit the bump stop.

I also need to move the engine mounts rearward to keep the engine in the stock location and cover the holes I cut in the cross members for A-arm clearance.

[cornfedbill]

The completed right side spring bucket and bump stop.

[cornfedbill]

I made brackets for a brace between the frame rails in front of the engine. Because the engine is two inches back in the subframe relative to the crossmember, I have more room for the brace. It will reduce flex caused by my 700 lb./inch springs.





As you can see, I am just beginning to patch the frame where I cut holes to make clearance for the raised lower control arms. They would contact the inside of the crossmembers otherwise. GM did not build in much extra clearance.

I suppose I could have used aftermarket control arms. But that would have defeated my design to make the suspension appear stock.

After I finish the brace and the frame patches, I need to make new motor mount pads behind the rear crossmember. It will be two inches rearward of the stock location.

[Ben@SpeedTech]

With the lowers moved upwards I imagine in my head bumpsteer and sway bar issues. What are you doing to compensate for the outer pick up points for the steering arm/ tie rod end and sway bar link being raised up? Will you be checking for lower ball joint bind at full droop? Just trying to imagine it all in my head...

If you need a template for the upper control arm mount Guldstrand mod I have one I can send copy to you.

[Build-It-Break-It]

I respect your drive to do things yourself but those welds scare me. Flux core at that. Those spring pockets and lower control arms take a beating and you don't want ANY of those welds to start to give on any road. I'd consider mocking everything up and taking it to a shop to get it done safely.

[cornfedbill]

With the lowers moved upwards I imagine in my head bumpsteer and sway bar issues. What are you doing to compensate for the outer pick up points for the steering arm/ tie rod end and sway bar link being raised up? Will you be checking for lower ball joint bind at full droop? Just trying to imagine it all in my head...If you need a template for the upper control arm mount Guldstrand mod I have one I can send copy to you.

Ben,

I have a copy of the Guldstrand mod. This is kind of like doing it upside down. Instead of moving the top pivot down, I moved the bottom one up.For bump steer, I plan to modify the drag link like one of the early iterations of the One Lap Camaro to move the inner tie rod points up. I may also use long outer tie rods that move the outer pivot downward.I think the angles will be okay.

I will check everything statically before I get too far.It is interesting how much work it took to move the pivots up only one inch. The benefit is that I can lower the car without making my lower control arms work at such an extreme angle. They will be nearly flat at ride height due to the mods I have made.So far it is going well. I am sure there are more challenges ahead of me.

The sway bar will be an issue. I haven't solved that yet.

[cornfedbill]

I respect your drive to do things yourself but those welds scare me. Flux core at that. Those spring pockets and lower control arms take a beating and you don't want ANY of those welds to start to give on any road. I'd consider mocking everything up and taking it to a shop to get it done safely.

Actually I have not made any welds on the greatest load bearing parts of the subframe. All of the critical contact points for the control arms are the original metal just redrilled. I am not worried.Flux core may not be pretty, but still can create a weld that will bond. 100,000 farmers cannot all be wrong...I have even seen brazed frames in the past that held up under racing conditions. Not everything must be welded with TIG or MIG welders.

[cornfedbill]

I cut the right frame horn off to move it back and down. I moved the subframe mounts back 2 inches, so I moved the frame horn back 2 inches also. I moved the frame mounts down only 1 inch. I lowered the frame horn 2 inches so I can droop the nose a bit.



The square bar with markings is to help me realign the frame horn once it was cut off.





The flange is for a cross-brace to stiffen the frame like is often seen on C3 Corvettes. It passes in front of the motor.


Sorry, this one was rotated. If you tilt your head you can see the difference between the two sides.

[cornfedbill]

I finished the driver side frame horn.

Now I need to decide how to mount the motor. I will use solid mounts, but want to move it right 2 inches and back 4 inches to help balance the car.

It seems easier to shift and reduce weight on the car than to reduce weight from the loose nut behind the wheel...

[cornfedbill]

I finished disassembling my Muncie. It's an M21 from a '68-'70 Corvette or Camaro I bought from a friend. He had a stash of good old Chevy parts. It was in need of a refresh.

I bought a rebuild kit from www.thegearbox.org. It has all I need.

I had to visit Harbor Freight to get a press though. It made it so much easier.

[cornfedbill]

I started mocking up the front suspension. With the lower control arm raised and the top control arm in the stock location, the movement is similar to the Guldstrand modification. The upper control arm looks very high. However, the ball joint is only about one inch above the pivot when lower arm is level (ride height).

[Centerforce]

This is really coming along! Glad that our products could be part of the build.

[cornfedbill]

This is really coming along! Glad that our products could be part of the build.

Thanks. Your products come highly recommended.