Project C4, 85 Corvette

[JustinG]

it was in 02 Jayray

[Steve85]

hope you get it resolved with as little cost to you as possible

it was in 02 Jayray

They did do good job on the repair. I was very surprised it wasn't totaled..I mean, a C4 with a flat tire is practically totaled.

I started my first home alignment. Took almost all the shims out of the top control arm mount to get -1.25* of camber. Left a few shims just to maintain caster and adjusted toe. Toe is close but I need to work on a better setup to measure. Just in taking some s turns on local roads I can tell it reallllly likes the additional camber. Need to put some csmber in the rear now. I'm going off this chart http://www.vettebrakes.com/align.htm

Been a great spring/summer so far with it. Driving it every weekend here and there. Took it out tonight for the first time in 3 weeks though...I freakin love it. Rowing through the gears as it pulls hard all the way to felony speeds. As it falls off at the top end there is an excitement that comes with anticipating the next shift into the torque peak, All without any of the refinement to rob me of any of the experience. Is it something I would want everyday, no, is it what I need to overwhelm me, yes.

[WRXtranceformed]

Awesome man those wheels look sick on your car!! That's one of the nicest C4s I've seen around in a while, really since Dave's old built Dart C4.

I know what you mean about being overwhelmed....I miss having a fast car to blast away the stress in

[Steve85]

Awesome man those wheels look sick on your car!! That's one of the nicest C4s I've seen around in a while, really since Dave's old built Dart C4.

I know what you mean about being overwhelmed....I miss having a fast car to blast away the stress in

Thanks Lee!

And speaking of Dave, he finally sold his last Saturday, he just posted to CF about it today. Such a shame, always loved his car.

[WRXtranceformed]

Ahh man that's a shame, that car was cool. He let me drive it once and it was a handful! I will say though that he was always having problems with getting it to run right, so it's probably a blessing.

[TorinoCobra070]

I don't think I've ever seen those wheels on a C4 before, but I really like it :thumbup:

[Steve85]

This shot was a real motivator to get my rear camber rods unfrozen..


C4s like-need as much camber as you can throw at them, negative that is. I recently did the front and will probably pick up some offset bushings to allow more up front.

Here is the camber rod position in the setup - black rod with blue tape. It bolts to the differential and to the bottom of the knuckle.


Here is the stock rod on top and the Vette Brakes and Products rod below.


The aftermarket rods are about 6-7 years old and I don't think I put anti-sieze on the rod end threads. I took the rod out and flipped it to the side so I could get pipe wrench + jack handle + my fat ass standing on it to break each rod end loose.



Butchered the rod. I did end up sanding it down and throwing some new paint on it.


Threads cleaned readied for GM anti-seize. Thank you "shop charges".


Back in with blue tape marked with an arrow to remind me which way to rotate to increase negative camber.


They spin real easy now so I'm at least another step closer to being able to get more out of this thing.

[Steve85]

Project Front Suspension

This is one of those restoration upgrade projects. All the bushings and ball joints are original. The bushings are clearly shot and will be replaced poly units and probably offset lower control arm bushings to get more camber. Stock setup is limited to about -1.25, offset bushings should allow -2.5+.

I tested the ball joints tonight and they seem tight but I'm going to replace them with some quality Moog units anyway. Once I can really push the car I would expect the old ones to give out soon.

Some before shots and tonights progress:

[V1GiLaNtE]

Nice! Glad so see some updates on this!

[ScottyB]

yikes, those are indeed dead bushings, good deal saying goodbye to them. do you happen to know the durometer increase on the offset ones you're looking at? or is it just basically "freaking stiff" :lol:

[Steve85]

Just freaking stiff :lol:

Tonight's update.

Got the other side off and started removing the upper ball joints and upper arm end bolts.

Cut the rivet head


Air hammer the now two pieces off


Air hammer the rivets down to allow next step


Air hammer the ball joint up and out then finish hammering rivets out


The threadlocker GM used is some heavy duty stuff, you have to melt it before hitting the nut with a 1/2" impact


So that's it for tonight. The next steps all require the use of a press, except the upper ball joint install.

And DO NOT open your detail cabinet when trying to get race car stuff done. Damn the temptation of pretty aluminum suspension parts that are clearly visible when your hood is up. These things clean up pretty well... (Before on the right of course)

[D_Eclipse9916]

Steve,

I have a press and you are more than welcome to borrow it instead of paying to have someone do it.

[Steve85]

Thanks DJ, appreciate it. I need to do some research to make sure I get it right and make a tool for the upper arm. The way you press the bar/bushings into the a-arm you have to be careful not to bend the arm. Also just ordered the offset bushings for the lower arm so when they come in I'll be ready.

[Steve85]

Thanks to DJ and Jason (NTIman) for access to shop press'.

This job was a BITCH! All because one of the bushing has to push all the way through the hole rather than half from each side.

It starts with making a brace for the A-arm, I used angle iron with a little notch cutout, so you can press out the crossbar that has the bushings. Out wasn't so bad, pressing the cross bar back in with the poly bushings took hours of lubing, resetting the stuff in the press, grinding a bit on the arm, hose clamps to keep the bushing from ballooning out while being pressed in, and so on....I wanted to get more pics but just didn't have it in me to try and document it very well. Didn't help that it took 90 minutes from Chantilly to Tysons Corner just to start the job.

It was getting late so I got both lower arms done and one upper done at DJs before I quit. Live to fight another day. A few days later, I contacted Jason who works at Kern Toyota in Winchester and he was gracious enough to sneak me in the back door after hours and help me use their press. He also managed to answer 1,472,569 questions from two little boys. Thanks for the tip to flip the assembly over and re-try!



Pressing out the lower control arm bushings was very straight forward.



I went with offset bushings here that push the lower control out 1/8". The set screws make sure they maintain the position.



You just drill and tap two holes, press in the bushings, align properly and put the screws in.





With some timely nice weather for garage work and the distractions visiting grandma and grandpa, I took my time cleaning everything and putting it all back together. It was very difficult not to get carried away trying to polish this stuff.



I think I am now ready for a complete alignment that will be somewhat aggressive.

[ScottyB]

bushing work is always a PITA, good on you for making it happen. what alignment specs are you shooting for?

[Steve85]

Starting point:
Front
Toe 1/16 out
Camber -2.5┬░
Caster 6┬░
Rear
Toe 1/8 in
Camber -1.7┬░

Max front camber w/out the offset bushings is about -1.5┬░, most are in the -1.25┬░, I think I was at -1.25┬░.

My car pushed real bad at autox and the track days I've done. Everything a C4 is sensitive to in terms of causing a push, I had. Monster rear tires relative to front (335rr vs 285fr), no camber (was 0 at last alignment check before I took out all the shims), limited caster, big front bar with poly bushings.

Oh yeah - I also cut my roll bar out this weekend.

My initial roll bar install was a disappointment. It's a 6 point done to NHRA specs. Turns out the guy who did it never did a Corvette before and said he'd never do one again. My fault for not checking him out more.

When I got the interior back together I could not move the seat all the way back. Seating position was pretty poor for me at 6'2". Bad enough that Mike Sarver even commented on it in my log book after an HPDE at Summit. I decided to cut out the cross bar behind the seat to have a new one put in.

New problem...the roll hoop is too far forward. Here it was in relation to the seat/headrest. When sitting in the car with helmet on, the helmet hits the roll hoop. If looking at the helmet from the side with the face to the right (at 3 o'clock) the helmet hits at the 11 o'clock position. So, back of the helmet but pretty high up on the back.

(Intentions are safe HPDE car, safety in accordance with performance, unlikely to ever to be full race car)

OUCH!!!



Bar was mounted to the floor just behind the seats and couldn't be laid back enough to allow the seat to go all the way back. New bar will mount where the frame rises up over rear wheel well as pictured below.



Took it for a spin w/out the roll bar, MUCH more comfortable. No real track days on the horizon for this car (an autox or two though) so the regular belts are back in while the I work on getting the hoop right.

[D_Eclipse9916]

Or get it all out and have Carlos with Autodynamix ro someone else put in a nice one. Roll bar/cage is mighty important to safety, get it done right (which it sounds like your goal is).

[Steve85]

It's pretty much all out, the hoop and rear down bars all came out as one piece and the door bars are removable swing outs that have not been in the car for a long time.

Yeah, and a cage is the right-right thing to do...dammit.

[NTIman]

A few days later, I contacted Jason who works at Kern Toyota in Winchester and he was gracious enough to sneak me in the back door after hours and help me use their press. He also managed to answer 1,472,569 questions from two little boys. Thanks for the tip to flip the assembly over and re-try!

Glad I could help! I knew we'd get that bushing in there, just didn't know how long we'd be. All in all it wasn't too bad.

[Steve85]

I'm really having a great time going "backwards" with this car.

I came to a fork in the road, when I removed the roll bar. A lot of the interior came out and it was decision time, what kind of car do I want? I want a fun reliable street car that feels and sounds like a racin car. I will do autox and HPDE on occasion for fun. I do not have the resources to make and use a race car. A cheaper car maybe? Well, a cheap car doesn't the add hours to the day or days to the weekend I would need to devote.

So, because not racecar, I spent the last two days gathering, cleaning and installing the AC components. Flushed it out, cleaned all the threads, cleaned the connections, all new O-rings (found a nice little car specific kit in stock at local Carquest). I bought an R134a retrofit kit that comes with a few cans, a gauge, and new service fittings but might not be the way to go. I'll see if AZ has a vac pump and gauges to rent since I need to pull the vacuum first anyway. I have very little AC experience so I might farm this out.

Other things I want to do:
Try Dynomax VT mufflers (90 day return policy) to quiet it down some
Install better roll bar (still a good idea, but won't be doing a cage with gutted interior)
Alignment - more street friendly, still solid camber but prolly 0 out toe
Blow up current engine, sell the good stuff and remaining parts from 434
Install LS based engine - this is looking a lot easier after some recent research, shouldn't need a new transmission :thumbup:

Looking forward to lots of driving time.