MONZORA redux: ‘65 Corvair + ‘94 Corvette mashup for 2019 Challenge

paranoid_android said:

I'm so sorry our plans for vegan awesomeness didn't work out yesterday.

Car would be done if you hadn’t bailed.*

*most untrue thing I’ve ever said 

In reply to aselmike :

Picked up a 2-1/8” hole saw today:

Measured and marked center for new hole, then got after it:

I knew the hole would have to be opened up a little more, so I duct-taped a length of 36-grit from a sanding belt and chased that through for a couple minutes:

I kept the shop vac running the whole time, with the hose next to the hole saw.  I’m sure this dust would be nasty.

and here’s the final fit:

In reply to AngryCorvair :

Don't know if anyone has told you but your hole looks big and wallowed out.

In reply to Stampie :

I’d be more concerned that there are two

remember, kids: consider how the wheel and tire move as the suspension travels and is adjusted, and plan your locating and attachment accordingly. For example, the C5 rear is an SLA, with camber adjustment made via cam bolt at forward bushing of LCA. Rotating this bolt moves the center of this bushing inboard or outboard, but it also moves the LBJ fore or aft accordingly, and quite a large amount. Over the full camber adjustment range, -1.5 (max) to -3.8 (min), the LBJ migrates forward so much that the wheel center moves forward a full inch at ride height. So, if you measured and located and fabbed attachments and tacked them with 3/4” gap from tire to front of wheel arch at min camber, your Tire will crash into the front of the wheel arch at your max camber. There is a little bit of relief though, as going from min to max camber also toes in the rear tire a large amount, so the toe link (behind steering axis) must be shortened to correct this. And increasing toe out pulls the wheel center rearward.  Net result is about a 1/4” gap between Tire and front of wheel arch.

TL;dr: achieving this:

Results in this:

Which is too dang close, considering component and bushing deflections, bump travel, body roll, etc. and I’m going to cut all my tacks and move the C5 frame and suspension rearward by 1/2”. Fortunately I didn’t melt too much wire, so it won’t take too long to make the corrections. At the same time, I’m adding a crossmember the full rail-to-rail width of the Corvair unibody, which will serve many purposes: limit twisting of Corvair rails over bumps; transmit lateral forces into body; and provide mounting points for exhaust and maybe even radiator.

And in other news, the engine adapter plate machining is underway:

Took a half-day vacation today, spent it in the machine shop, making brackets to ease the connection of C5 rear frame cut to Corvair unibody. Man, it seems like I’ve been using that phrase for *way* too long.  Anyway, start with a foot of 2x2x.065 square tube from the scrap bin at Alro:

drill seventy-seven (!) pilot holes, followed by the step bit up to 1/2”:

Then split it lengthwise in 2 (shown), then into 4 pieces 1x1 (not shown):

Then cut those down to a pile of 2” and 3” segments:

Coming soon: setting up locating blocks and stitching this turd back together!

And since there was nobody waiting at home for me, I spent a few minutes extra and finished modding the rear spring.  Just needed to drill a couple 3/16” thru-holes for securing the steel reinforcements:

I think I’m going to sit by the desktop and hit refresh a thousand times on the Challenge scoring sheet, instead of working in the garage tonight. But I’m gonna hit it hard this weekend.

Onward to Challenge 2020!!!  Following this thread faithfully as a former Corvair racer (turbo 66 in the SCCA Pro Rally series) and 1994 C4 owner.

AngryCorvair said:

And since there was nobody waiting at home for me, I spent a few minutes extra and finished modding the rear spring.  Just needed to drill a couple 3/16” thru-holes for securing the steel reinforcements:

I think I’m going to sit by the desktop and hit refresh a thousand times on the Challenge scoring sheet, instead of working in the garage tonight. But I’m gonna hit it hard this weekend.

Very tidy work on that.  Did you decide what fasteners to use?

In reply to Jim Pettengill :

Hey Jim, good to hear from you! I will keep this thread updated as I pick away at it, but I suspect there won’t be much to post between Thanksgiving and Easter, as thats “too cold to work in the garage” season for me.

paranoid_android said:

Very tidy work on that.  Did you decide what fasteners to use?

Since they really just keep things aligned during the assembly process and prevent rattling as it ages, I’m going to use some #12 x 1.25” machine screws with nylock nuts, as suggested by the other Patrick.

Several big chunks of weekend got eaten up by other things (rescuing a trailer, fixing a flakey minivan power sliding door, being lazy), but I did get a little bit of work done in the garage.  I repurposed some C5 rear crash beam:

Into some patches to enclose the rear UCA clearance notches in the Corvair rails:

Hmmm, my phone says there are no photos.  I disagree.  I’ll try again later.

A little death wheel and a little flap disc and a little wire feed and:

Imagine a near mirror image on the driver’s side and you’re pretty much all caught up.  I wrapped up the weekend with a little CAD work but didn’t get those pieces cut today so I’ll update later in the week.  Or next week.  But definitely before 12/16 because that’s when I’m having the carpal tunnel surgery on my right hand.

I'm going to do my best to stop by the day before thanksgiving if you're going to be home 

In reply to Patrick :

I’ll be home. I take vaca the Mon thru Wed of Thanksgiving week pretty much every year.  3 days of vaca nets 9 consecutive days away from the office.

In reply to AngryCorvair :

Feel free to ignore my advice, but PLEASE listen to it...do NOT operate a grinder or any hand tool that causes vibrations for AT LEAST 6 weeks after your surgery.

Ask me how I know...

Gingerbeardman said:

In reply to AngryCorvair :

Feel free to ignore my advice, but PLEASE listen to it...do NOT operate a grinder or any hand tool that causes vibrations for AT LEAST 6 weeks after your surgery.

Ask me how I know...

Sounds like excellent advice.

And a great reason to buy a plasma cutter.

TVR Scott said:

Gingerbeardman said:

In reply to AngryCorvair :

Feel free to ignore my advice, but PLEASE listen to it...do NOT operate a grinder or any hand tool that causes vibrations for AT LEAST 6 weeks after your surgery.

Ask me how I know...

Sounds like excellent advice.

And a great reason to buy a plasma cutter.

I’ll get my Doctor to sign off on the plasma cutter, then I can buy it with pre-tax HSA $.  

AngryCorvair said:

TVR Scott said:

Gingerbeardman said:

In reply to AngryCorvair :

Feel free to ignore my advice, but PLEASE listen to it...do NOT operate a grinder or any hand tool that causes vibrations for AT LEAST 6 weeks after your surgery.

Ask me how I know...

Sounds like excellent advice.

And a great reason to buy a plasma cutter.

I’ll get my Doctor to sign off on the plasma cutter, then I can buy it with pre-tax HSA $.  

If you can pull that off, I want to visit your Doc! 

In reply to AngryCorvair :

It's all coming together...

Stuck around for a while after work to use the drill press and band saw, turning CAD into 16-gauge cold rolled reality:

In reply to AngryCorvair :

I thought you were making your own APC pedal covers for a second there...

In reply to Pete Gossett :

Or a weird robo-face...

The truth is that these are much less artsy than that.  They’re just reinforcement plates to spread the bump forces over larger areas of the Corvair rails.  I was kept away from MonZora last night by a minivan with a dead battery, but I hope to get a couple of these welded in tonight.

Under threat of 3-7” of snowfall tonight, I spent a good chunk of the day swapping summers for winters.

But prior to all that, I got to spend some quality time with the wire-feed welder:

Picked up some 1” square 14ga last week, hard to explain how I’m going to tie it in so I’ll just post pix of the process and results.

Dang, ten days since the last update? I’ve made a little progress in that time. Tacked in one of the fore-aft attachments on each side.  Here’s the driver’s side:

And here’s the passenger’s side:

Then I moved on to the rearmost attachments, which tie into the mount for UCA rear bushing.  Again, driver’s side:

And passenger’s side:

With those bits in place, I can disassemble the suspension and remove the cradle, so I’ll have better access for fitting and welding the additional attachments. It will also give me room to apply some of that magical make-it-disappear satin black spray paint after the welding is done.

Got home from work and found a surprise on the front porch:

No, not the dog.  That’s Bella, and that’s her happy face.  She’s happy because the engine to transaxle adapter plate is here!