After reading up on what constitutes a good suspension for handling, I opted to keep the stock spring rates to maintain height and softness, but upgrade the anti-roll bar to increase stiffness and steering response. Ninety percent of my driving is commuter or back roads touring, so handling and comfort are primary. I don't want the suspension so stiff it's like riding in an ox cart.
FRONT SPRINGS: The 79 Stingrays were delivered with one of two possible spring rates: one for cars with a/c and one for cars without. Since my car originally had no a/c, the softer spring was installed. I plan to install a modified factory a/c, which normally calls for the stiffer springs. However, I'm also installing aluminum heads, intake, and radiator, so this should offset the a/c weight gain. I decided to keep the stock springs and see whether I like them in the new set-up. Fortunately they are fairly inexpensive and easy to replace.
COIL SPRING ISOLATORS: I was intrigued by rubber coil spring isolators I found during a parts search. I dug around to see if anyone had used them, and of course there were folks that had. Some liked them, some didn't, and some couldn't tell a difference. They were not standard equipment on Stingrays, but I thought they might be worth a try. To my thinking, the front suspension is isolated from the frame except where the spring sits in the shock tower. They are inexpensive and at worst will do nothing.
SWAY BAR: To increase stiffness and handling, I went with the 1.125" factory anti-sway bar from the Gymkhana suspension option. I chose this because I knew it would provide the best fit for the stock suspension geometry while providing adequate stiffness for my needs. Factory sway bars have a bend and twist at the ends to line the bushings and linkage up with the lower control arm bushing pocket. Some aftermarket bars do not have this bend, and the result is reduced bushing life.
BUSHINGS: I'm installing polyurethane bushings. I have experience with these in the past and like the extra stiffness and response they impart to the front end.
SHOCKS: I'm still researching this. Of course, the QA-1s are very attractive, but also very expensive and probably more than I need. I'm leaning towards Koni, and Bilstein gets good reviews also. Either way, I need a shock that has good adjustable rebound to keep the rear end out of the air.
COATING: I decided to powder coat the suspension parts, where applicable. It's easier than painting and the parts can be completely coated. I like that powder coat is very durable, chemically resistant to nearly everything but acetone, flexible, and generally easy to apply. I am a novice at powder coating and painting, and I learned a lot in the process. I think the parts turned out better than if I had painted them.
Modifications: None
Upgrades: Four
- Replaced stock anti-sway bar with the heavy duty 1.125" sway bar from the factory optional Gymkhana suspension package (E-bay)
- Replaced stock rubber bushings with polyurethane bushings for more responsive handling (Energy Suspension 3.3108 - Control arms; 9.5112 - sway bar bracket; and 9.812 - sway bar end linkage)
- Installed coil spring isolators to reduce noise and vibration transfer (Metro BN-110)
- Installed performance adjustable shocks (TBD)
Upper Control Arms
I didn't take any "before" upper control arm pictures, but this lower control arm picture gives a general idea of the condition the control arms were in. Fortunately they were in good shape. Rebuilding them was strictly a remove, clean, paint, and install / replace job. This walk through shows a way to insert polyurethane bushings. These bushings come in three pieces: outer bushing sleeve, polyurethane bushing, and inner sleeve. The stock rubber bushings are a single piece. If you have those, this walk through will not work.
Getting the old hardware off can be a challenge. I used a 2 lb hammer and cold chisel to remove the rivet heads from the ball joint rivets, and an electric impact hammer to remove the old bushings from the control arms. An air chisel would've worked better but didn't have my air compressor at the time.
As you can see in this picture, I taped off the bushing seat before powder coating.
My first attempt at bushing installation involved the misguided use of a 4 lb dead blow hammer. I cold soaked the bushing sleeves in the freezer for a week and had to beat the crap out of them to get them seated.
I found several posts on the forum discussing a tool folks had made to get the bushing sleeves pressed in. I fashioned upper and lower control arm bushing tools from 1.5" and 2" conduit pipe. I measured the inner distance between the control arm forks and cut the pipe to that length, then cut it in half lengthwise. For the lower control arms you will also need to make a spacer that fits between the inner and outer bushing seats. I covered mine with tape to protect the powder coat and help keep the tool from popping out.
This picture shows the tool in action. I didn't think to take a picture while I was pressing the bushings, so I borrowed one from the forum.
Generally, the pivot shaft must be placed in the arm after the first outer bushing sleeve is in place. Before assembly, clean the pivot shaft ends with fine grit sandpaper so the inner sleeve goes on smoothly. Here is an upper control arm with outer bushings and pivot rod. It's ready for the bushings and final assembly.
Polyurethane bushings squeak if not lubricated. I ordered and extra container of the lubricant and slathered it on. Be sure to wear rubber gloves because that stuff is thick, messy, and sticks to everything. Here's the bushing lubed and inserted over the inner bushing sleeve. It's ready for the end cap.
After seating the bushing by hand, I noticed the pivot shaft seemed off center at the other end, indicating the control arm could be bent. I inspected them before inserting the sleeves and they seemed fine. I went went ahead and placed the bolt and end cap on and tightened it up. This straightened out the pivot shaft. I put the other bushing in and tightened the end caps to torque spec.
Since polyurethane bushings rotate freely in their sleeves, the pivot shaft end caps can be torqued on the bench. I clamped the pivot shafts in a bench vise, put red Loc-Tite on the end bolts, and torqued them to 35 ft-lbs each. The completed upper control arm bushing installation is shown at right.
The final step was installing the ball joint. The original ones were riveted, but I'm not going for NACRS points, so I went with a MOOG replacement that bolts in. I used red Loc-Tite on those as well and torqued them to 25 ft-lbs per the installation instructions.
Lower Control Arm
After I disassembled the lower control arms, I discovered the pivot shaft on the passenger side was drilled off-center. I had previously installed polyurethane bushings and had the retaining bolt back out twice on the passenger side lower control arm. While I'm sure these cars had tolerances, this was pretty pronounced.
My theory is that for rubber bushings mated to the sleeve, this is OK. However, polyurethane bushings are much harder, don't compress well, and aren't mated to the sleeve. The off-center end cap bolt hole caused the end cap to be off-center as well. Because the end caps are slightly curved, a pinch point was formed on the bushing between the cap and outer sleeve opposite the off-set. Since these bushings rotate in the sleeve, rotational motion was transferred at the pinch point and started working the bolt loose. Once that happened, the bushing backed out and kept pressure on the end cap further loosening the bolt until it came out of the hole. It's just a theory, but since I'm reinstalling polyurethane and planning to occasionally auto-cross, I'm not taking any chances. I found a NOS replacement shaft on E-bay for $40.
The lower control arm bushing installation is practically the same with one important exception: The pivot shaft must be installed correctly and before either outer bushing sleeve. When the pivot shaft is correctly installed, the T end is on the same side as the sway bar pocket. When using the bushing tool, don't forget the spacer between the bushing seats or you will deform the control arm.
To complete the job, add a new bumper and ball joint.
Front Suspension Installation
Before I could put the front suspension together, I had to complete the spindle and rotor rebuild. The first thing I did was install the upper control arm bump stops, then the spreader bar and upper control arms together, and then the lower control arms. Then I attached the spindle to the lower control arm With assistance, I attached the isolator to the spring and compressed it until the spindle could be attached to the upper control arm. The last step was installing the larger sway bar. I used a polyurethane bushing set for the end links and the frame mount. These were liberally lubricated to guard against squeaking. I will wait until the car is resting on the ground with full weight before tightening the end link bolts.
SUMMARY: This job was probably a 6 out of 10. Getting the old hardware removed can be difficult, especially the bushing sleeves. Also, pressing the new bushings in with a homemade tool was a little hair raising. The tool has to be fairly accurately made or else the control arms will be deformed and it must also be able to withstand the forces needed to get the bushings installed.
Front Suspension