64 Vette….Rebuild 2.0

[folkenheath]

There will come a point where the pressure doesn't push on the center enough so you start to lose traction instead of gaining from lengthening the contact patch, every tire and rim combo is different. I wouldn't jump 5 psi. Maybe try 18, if it likes it, you can try 17, or maybe 16. But with a radial and your tire size my guess is 15 might be too low, but you can try it and see.

 

[shady]

Any lower than 20 I'd mark the tire and verify that your not spinning the wheel under hard launch.

 

[76zimmer]

Well no more passes this year. This was to be the last weekend of TNT and its been raining alot. Better luck next year I guess.

I pulled the plugs last week and lashed the valves a bit tighter (.022 to .015) these plugs have a couple hundred miles and many full throttle blasts on them. mostly 90 octane alcohol free fuel, 36* timing and 71/77 jets. Closer magnification inspection shows no sign of detonation (no aluminum sparkles on the plug porcelain).

 

[76zimmer]

Ive been watching this car in the FAST series….560 c.i. THM400, still running the IRS with 12 bolt internals and 31 spline axles w 1480 joints. He just ended the year w a 9.10 @ 148. Amazing to do on a 7” polyglas tire.

 

[76zimmer]

I cut up the frame from that crashed 79, and will be using it for mocking up a few parts for the new suspension and axle upgrades.
A traction bar from spring mounting pad to front differential mounting crossmember.
And some upper control rods that will keep the trailing arm in position in case of a ujoint/halfshaft failure.
And some safety loops for the driveshaft and halfshafts.
Headed to Iron Monger racing in a few weeks for some fab work.

 

[ZooMad75]

Awesome. Though I don't have clue how the traction bar would even get installed on the IRS. I just can't picture the placement. But great idea on using the chassis chunk for the mock up.

 

[folkenheath]

Is this traction bar basically a brace for the differential housing Dave?

 

[76zimmer]

The original GM engineering was to use the rear diff cover as the mounting point for the diff assy. That cover bolts to an overhead crossmember (red circles) and that crossmember bolts to the frame (outer red circles). The lower part of the diff housing has a bolt on bracket, that extends forward and bolts to a frame crossmember tab and has a “cushion” mounted to reduce vibrations, also allowing some flex. That tab has been known to be a weak point, especially if rusted at all. Mine is in great condition, but it can be improved upon.

A traction bar will bolt to the transverse mounted spring plate (the green circle), and also the diff housing (replacing the factory bracket) and will bolt to the frame tab in the factory location. It also has a snubber that will contact the stout main crossmember providing zero movement of the diff if desired.

 

[ZooMad75]

Thanks for the visual. Makes more sense for my brain. I can totally see how the nose of the pinion would possibly rise up under acceleration and with the mount coming only off the rear cover I can see why it could twist pretty hard right there.

 

[82355]

You should hear the noise it makes if you do a burn out without that lower front support!

Martin

 

[folkenheath]

The original GM engineering was to use the rear diff cover as the mounting point for the diff assy. That cover bolts to an overhead crossmember (red circles) and that crossmember bolts to the frame (outer red circles). The lower part of the diff housing has a bolt on bracket, that extends forward and bolts to a frame crossmember tab and has a “cushion” mounted to reduce vibrations, also allowing some flex. That tab has been known to be a weak point, especially if rusted at all. Mine is in great condition, but it can be improved upon.

A traction bar will bolt to the transverse mounted spring plate (the green circle), and also the diff housing (replacing the factory bracket) and will bolt to the frame tab in the factory location. It also has a snubber that will contact the stout main crossmember providing zero movement of the diff if desired.

That might be the shortest traction bar discussion ever...

And some upper control rods that will keep the trailing arm in position in case of a ujoint/halfshaft failure.

I like the idea of adding an upper control link, I've always thought it crazy the half shaft is the upper link through u joints...

 

[76zimmer]

Had a shoulder issue kept me out several days, gotta play easy with it for a while. Trying to hold off surgery if possible.
I finally got the parts on the mock-up frame to start some fab ideas and measurements for the upper control links. Made a few sketches for measurements and upcoming fab work at Iron Monger racing. Still have more preliminary work to do in the next week.

 

[folkenheath]

So is the halfshaft center to center distance and the lower link center to center all 13.5"? They have to be the same so the arc doesn't bind up the half shaft correct? Since the half shaft doesn't have any slip to it?

I suppose there might be some way they could both be shorter, maybe the half shaft is 13 and the upper link can be 12"? I would have to make a model of that to make sure it doesn't bind, you could feel it in your mockup with no spring I suppose. I guess it depends on if you want it better for drag racing or cornering.

When you are doing all this work, can you put a coilover shock in instead of a leaf spring? Or you are leaving the leaf spring because it works fine with a good shock and a leaf spring?

I like the upgrades Dave, hope your shoulder gets better for you.

 

[76zimmer]

The lower link is a little longer than the halfshaft, hence the way a Vette (C2 & C3’s) squats on hard acceleration.
The upper link I’m installing will be the same length as the halfshaft and also be parallel with the halfshaft, therefore maintaining the same alignment if a halfshaft comes apart.
I ordered a 2” shorter length main leaf, (made by Deaver) for the spring pack….That is whats in my mock-up picture.
I will use a somewhat stiff springpack for minimal squat and an adjustable shock. There is a kit called Sharkbite for a few grand to replace the leaf and standsrd shock, but I’m not diving in that far at this point. Success can be had with leaf and shock tuning….and good tires!

 

[AJMBLAZER]

Watched a video on Jaguar E type IRS and realized I recognized it’s principles.

 

[76zimmer]

Traction bar mock up, welding test fit and powder.
I took a spare housing, rear cover, spring mockup pack, lower camber bar bracket, and front mount to give as best of a representative setup as possible. Lifted the diff housing up onto the bench and my wrist popped, hurt like running naked into a cactus. Now I can’t even lift a drink.
Kert put a lot of time in building this thing to meet my requirements and then blasted and powder coated it in Polished Aluminum powder.
Now Working on the upper strut rod bracket, bars, and a few additional pieces I will dial in when it’s all on the frame.

 

[centexk5]

Wrist pain hurts. I’ve got a tendon that’ll flair every now and again on my right hand and I won’t be able to lift anything. Gotta put a brace on for about 24hrs to calm it down.

 

[Bent77]

Hurt like running naked into a cactus huh? I guess that explains Moab a bit. To think this whole time we’ve been calling you Stroker McJerk

 

[76zimmer]

Fresh powder

 

[76zimmer]

Wrist pain hurts. I’ve got a tendon that’ll flair every now and again on my right hand and I won’t be able to lift anything. Gotta put a brace on for about 24hrs to calm it down.

Yeah been nursing it for a week now and something popped on Thursday.
Probably go to the orthopedic dr next week when I get back home.

Hurt like running naked into a cactus huh? I guess that explains Moab a bit. To think this whole time we’ve been calling you Stroker McJerk

Why of all the lowdown dirty rotten scoundrels I’ve ever been associated with…..you know!