69427

Quick simple question. Are all the model year parts (both C2 and C3) the same design (same arm lengths and angles)?

My guess is Yes, but I'm open to correction.

Thanks for any constructive input.

69ttop502

ignatz

For what it's worth, I've been able to break the welds and move the clutch fork arm around and reweld it.

buns

buns

gkull

Mine came with 2 holes from Keisler Engineering. I drilled another one down lower, so it moves the lower arm faster for less pedal travel to disengage the clutch.

are you going to be at the 24 hours of daytona race on Saturday. We were thinking about flying in

69427

Lotsa good information here, gentlemen. I do appreciate it.

I'm currently cutting up some aluminum tubing and plate to make a slightly lighter z-bar (I'm running out of ideas to get additional weight off the front of the car). I have a "spare" z-bar on the shelf to use while I make the welding jig, but I don't know the actual vehicle it came off of. I'll do some measurements of this bar, and then see if it's better to just pull the current one off the car to use when making the welding jig.

Thanks again.

pauldana

Hardness on the Z bar....

I also put in an extra hole so as to have a quicker and shorter clutch throw.. BUT,,,,,,,,,,,,,,,,,,,,,................ .............

the mettle is friggen hard!!!! I could NOT drill this mettle... so I had to have my Zbar water jetted to get the third hole..

Big2Bird

Your now in that $100@lb zone.

Big2Bird

Mike. Do this one. My son bought me the strut kit from speed direct. $160.
It weighs nothing. Make your own brackets out of alum, and buy the cylinder. Takes 3 lbs off up high. And, it works far better. Even Doug likes it, and he is NCRS crazy.

69427

Well, I hope the zone I'm in isn't quite that expensive.

To be honest, half the reason I've been on this path is just for the pure engineering enjoyment of it (most hobbies are money pits of some sort). I spent most of my adult life doing circuit design, and now I'm finally getting to get some return on my money for all the tuition dollars I spent wading through the mechanical engineering classes my freshman and sophomore years.

Oh, I agree on changing the hood prop (the weight's up front and up high). I did the hood prop/bracket setup in aluminum several years back. I did have to change the (version 1 aluminum) prop rod to a steel piece, as the aluminum rod was either too flexible or too big aesthetically.

Big2Bird

How about bumper brackets? They weigh a bunch.(I should have known about the hood thing).
The 81 has this massive battering ram that must weigh 40lbs.

69427

The rears are aluminum. The front supports are stock, as I haven't come up with a combo that I'm comfortable with yet.

derekderek

I think you will find why the Z-bar metal is too hard to drill as soon as you step on the clutch with that aluminum Z-bar. The big heavy bumper brackets are a safety issue and there are many arguments when people wanna convert to 68-72 bumpers.

69427

Is it your thought that I'm unaware of material strengths, forces and torques, and possible non-engineering reasons why Chevy put boatloads of steel and cast iron in our cars instead of aluminum, titanium, and magnesium?

Just curious.

derekderek

they used boat loads of cheap soft steel because, like every other 60's to 80's car it was designed to last about 5 minutes longer than the warranty period. fed govt mandated better crash safety so they used more. once cars cost 50 to 60k new and fed govt mandates certain fuel economy standards, out comes the Aluminum, Magnesium and composites... they used hard steel in the z-bar cuz the cheap soft stuff didn't hold up. do I know you personally and think you have no idea what you are doing? no. do i think the AL pivot will hold up? i hope i am wrong... but there are MANY more people on this forum that can fab a z-bar than can design one.

69427

That's right, sport, you don't know me. You have no clue what my educational/technical background is. You also did not have the common courtesy to ask me any details on the construction of this part, nor any of the calculations I went through to pick out the pieces I intend to use before you pronounced that this endeavor would be a surprise/failure.

Did I at least get this side part of the project correct?

69427

I measured the arm angle on my spare bracket. It's the early small block version. So, looks like I'll just pull the present shaft off of the car to weld up the jig. My thanks to buns for the information here.

BLUE1972

If the AL fails , you could go to Dupont Vespel Bearings and Hemi rod ends. It may help. You would have to machine a step in the tube or insert another tube to make the step.

Experimenting is always fun .. Best of luck..

Corvettes White

Made this for fun. But forgot how it went together. Came across this post. George