Project Elvira – Intro and Update

phantomjock

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Project Elvira – Intro and Update

The following pic is my cartoon work plan. Not so much a spreadsheet or PERT Chart, but a means to capture any method to my madness.
I have had plenty of spare time on my hands while still in physical therapy from my shunt at Sebring last Labor Day. I’ll add a few details on that later.

My 1978 Corvette has followed a number of changes since new. With this major revision, I find it necessary to lay out a plan of sorts and settle on a direction – and help me keep my focus. I can’t guarantee this will keep me from a few, “While-I’m-At-It”, but maybe will keep my ordering of parts organized.

Some of the things I’ve wanted to work include; shifting the engine and transmission aft, raising the differential, lowering the car, dual wishbone IRS, numerous aero-mods, tilt-forward radiator, gull-wing doors, and a few other mad-ideas. As a result, the car will now only compete in SCCA Special Production - Over (engine size)/SPO, NASA Super Unlimited SU. This means Regional-Only Competition. But, I suppose as an A-Mod in Autocross that opens National - hah-Hah! But I have a number of tracks within a 5-8 hour tow/drive to get my fill of track time and empty the bank account.

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For each element of the effort, I’ll start at the nose and work to the tail outlining any progress.
As an outline of my posts – I’ll try and follow this order:
BODY WORK
MECHANICAL/Metal Work
SUSPENSION
INTERIOR
ENGINE
COOLING SYSTEMS
MISCELLANEOUS
SAFETY
PAINT AND FINISH – HAH!
TECH INSPECTION - When finished!!!

I’ll try and follow this maxim:
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Cheers - Jim
 

phantomjock

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PJ, why the reverse gills?

Ralphy
Ralphy -
Uhhhh, they look so cool. :D
No, I needed the space behind to mount the oil/transmission radiators. The fit was just too close without reversing.

BTW, I got them from a guy that goes by "Fiberglass Mike." Quality is good and price fair, as I recall. 13Bats has done some work with him - he's here infrequently - a MAKO-guy. Hangs out at the MAKO site.

Good question.


denpo -
Denis - much of the stuff I'll post will be summary, rather than a; "watch while I build it. " Sort of give a fast-forward, to the work already accomplished. I'll try and pace my postings to get some work done at the same time.

MYBAD79 -
Karsten -- Thanks for the encouragement. I hope it turns out half as nice as your work!

Cheers - Jim
 

Ralphy

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I just thought since you were reversing/catching air you could duct the air. Say to the brakes, driver, etc...

Edited:
Reading again is that where the coolers are going?

Ralphy
 
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phantomjock

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What's the weight target on this project?

Ouch! I'd really like to be at 2800#s. [Wouldn't we all?]

But, I've watched your struggle to get the weight down - while keeping a stock-looking C3. Because this will still be street legal (it is in FL, so a little easier) I'll still do lights etc. Even though the interior is gutted - the cage makes up a lot of the weight. But, the aluminum buckets will shave a pound or two over the stock, or even Sparco seats.

Replacing glass with the lexan is a bennie, and no side windows except for transport - class rules require open.

I'm making the flares just now - and keeping their weights down. The first 2 are out of the mold awaiting trim and weigh 3# each -- but still to be glassed to body.

The Gull Wing doors are waiting trim, but they are gutted - no steel bars - NASCAR door bars for that. This next week I'll be tackling that body work - I think.

Aluminum radiator saves some weight. Aluminum heads on the 383 shave pounds off the double humps I had. The Webers and IR intake manifold probably plus up the weight a bit.

Suspension is helping bring some of the weight down - up front anyway. The SPCs are lighter and I believe the LCAs are too. Having the transverse composite spring eliminates the anti-roll bar so a bit of saving there as well.
CV axles weigh in at 20# each vs the half shafts and U-Joints. Got rid of the battering ram, all the pneumatics for the lights etc - so only time will tell what is works out to.

Much longer "skirt" there than I intended. But, the short answer is shooting below 3000# -- lower better.

Cheers - Jim
 

phantomjock

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Project Elvira Some Body Work

Cowl Induction Scoop:
This component is awaiting fairing, sanding, and prep. I got a great deal on a cowl induction scoop but needed to widen it to mate to hood and roll to match radiator exhaust opening.

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All this to match Weber clearance. I checked with Jim Ingelese (Weber tech-supreme) and he recommended a minimum of 2 inches clearance. Easy for the rear – not so easy for those 4 up front.
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Drivers eye view:
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This is a BIG cowl:
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I may need to make it out of Clear Lexan in the future. Something like this – but a Cowl Induction.
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But for now, here is how I worked it.

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Widening was a cut and paste action. Sunny yesterday, so I got working some of the finish. That is just “dry-fitted” and it fits better than in this pic. And the finish is much better now too.

Warmed air from the Radiator may prove to be a problem – so may “turbulate” with a gurney flap – or some “Zs” testing will tell – for now it is, “… sand, fair and sand some more. Press on regardless.”


Jobs current in the garage 7-8 Dec ‘14:
BODYWORK:
Fender Flares 1 complete, second pending
Rear Fascia – the fill in plate for the Kamm-back​

Fender Flares Background/Update
I built the buck in 2012-13. I started with a set of L-88 Mudflap flares from a rear clip (picked up from a buddy in 2009):
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Then cut them and made a dual Mudflap flare. Best seen here.
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Then I built the mold on the buck:
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Success! Pulled the new mold from the buck – Now I’ll store the buck in the attic I guess.
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Then, layup a flare in the mold. I added a bit of aluminum flashing to give an inset to the flare [picture follows]. Will look nice, add some strength, but may cut it off after all the effort of working it into the mold, and laying up.
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First flare came out great.

Second had a gel coat fail and I now use it as a reminder of, “PATIENCE GRASSHOPPER…”
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So sand off all the gelcoat from the failed flare, re shoot the mold with tooling gelcoat, wax (7 times), PVA release, then shoot the gelcoat for the new flare.
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Today I’ll layup Flare #2.

Other BODYWORK in the Garage:
Rear Fascia Lay-up
Denis has been wondering about various rear end treatments for his build. I'm partial to eliminating the "parachute:
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or as seen on the Chaparral:
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Not much to see here, but the table I used to pull the vacuum on the piece:
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I built the vacuum a few years back. I was pulling -25psi on the piece nice and flat and smooth as glass. The table is a sliding glass door. I still wax it to aid in release, but no PVA. Any resin run-off is easily cleaned with a razor blade.

That's the update for now. Got my bits for the IRS build back from my machinist - may cover that next.

Cheers - Jim
 

phantomjock

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Thanks for the comments and encouragement. Some of what I’m posting has already been completed – or in progress. [The result of me not being focused on posting the efforts until now.] So what is happening now?

Got four good flares – and a spare to cut up and use for fitting/positioning on the rear and front clips:

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I adjusted my layup schedule, as I made each one so they are slightly different weights. They have been only rough trimmed, and I’ll need to trim the inside lips. The first was just over 5 ½ pounds, and the last right at 4 ¼ pounds. I don’t know how that compares to Eckler’s or ACI, but I am pleased with the output and their rigidity. My work with the buck and mold finished – those are now tucked away in the attic. She Who Must Be Obeyed wouldn’t stand for anymore car parts in the living room. :pprrtt:

A few years back, when I first started asking questions about a dual wishbone build for the C3, Twin Turbo suggested that I just pick a Jaguar rear suspension and be done with it. [ http://vettemod.com/forum/showthread.php?t=7751 ] Well, as you look at these pictures, you’ll see in a bit, there are a few similarities in my execution of my Dual Wishbone C3 IRS.

Here is a Jag IRS:
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Note the internal brakes. Hmm, that is kinda cool. As I was working out the “how to mate the shaft to the differential” I settled on using flanged output shafts (Tom’s Differentials) and then cut/weld C5/6 output shafts to a companion flange like so:

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Well a bit of research, and I learned about floating rotor hats, and how expensive they are – but huge advantages. Here is a diagram of one approach:

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And another:

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I drew up a quickie sketch and talked with my machinist. He said very do-able.

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Next day, armed with a couple disks of 6061 T6 Aluminum,

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my other bits and pieces, C5/6 output shafts, companion flange, and a couple of bobbins, I was off to his shop

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A few days later he had milled the new floating rotor hats, (Comparison of the two shown here)

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matched the companion flange to the Tom’s Flanged Output Shafts and mated/welded in the C5/6 output shafts in the companion flanges.
Here are the results:

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I needed to open the differential to remove and replace the output shafts. Here are the parts pieced together to link the C3 Differential to the C5/6 CV axles. Naturally I couldn't resist mocking the assembly up to see what I'd created:

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The brakes will be mounted on a frame and the chassis but well inboard. I’ve calculated (weighed) the resulting difference in un-sprung weight as nearly 16 pounds per side!

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Another benefit of inboard brakes, no heating of the wheel bearings from the brakes; when the rotor expands from heat, the floating rotor hat and bobbin assembly allows the rotor to expand. With less stress on the rotor it is less likely to shatter; shorter brake lines are a minor benefit; but, some complain of increased complication to access to change out brake pads – but as the entire rear clip is a flip-up, that should make for better access; and lastly, some complications in getting air ducted to the rotors. The heat will be transmitted to the differential, but I have plumbed and planned a diff-cooler setup and that will help in that regard. Cooling the rotors will get sorted out.

Here I’ve done the fiddling and some detailing of the diff/brake assembly:

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Now, I need to clean the garage and bring the chassis in in out of the rain and get ready to put the project in suspended animation for 3 months for our trip to South East Asia – I gotta go launch and move the sailboat up to Thailand and get some work done there. I’ll add more of the rest of the IRS build – once I get the chassis in the garage.

I built some “Rolling Jack Stands” to hold the chassis and let me move it around. [Not seen are the angles I welded inside the 12 Ton Jack Stands, then through bolted the assembly to 1000 pound capacity furniture haulers.]

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I will weld 4 “receivers" to the chassis to keep the stands secure and be the planned lifting points. Then, I’ll pull and store the wheels and tires, then dry fitting the body for storage.

More pictures and details in next posting. For now, everyone get your Christmas shopping done! :beer:

Cheers - Jim
 

mrvette

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P J what is your addy?? I need do a reverse Santa run out this week and relieve you of your labors there......:shocking:

but seriously, those rotors look to large inboard like that, I ASSume you keeping the same stock upper cross car, not lowering the diffy, much less on the spring mount/bottom end.

:1st::beer:
 

phantomjock

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Gene - Better hurry on that Santa Run! I'm west of you - FWB! Those are good questions.

The rear sub-frame is very modified. Tomorrow (or the next day) I should have the garage emptied enough to get the chassis in. Then, I'll mock up the diff, rotors etc., and we'll see where we are. I may have to move the mounting points I was using for the rear toe-control arms, but my tape measure says I have room for the rotors, calipers and mounting bits.

No lower spring - coil-overs on rear now and I raised the diff by 2 inches and removed the cross member and sombrero setup. The diff now is mounted to the aft-most member that is just ahead of the fuel tank, and 2 lower runners of the sub-frame.

This pic doesn't show well, and those control arms and mounts and uprights have all been changed out now: 1269549736b1afc5d
I've pointed out where the 2 sub-frame runners are on the bottom, but you can't quite see the mount to the aft cross-member. I'll take new pics in a day or so.

This pic is looking up from the bottom. [Well, really the frame was on its side - but the same view...]

Cheers - Jim
 

phantomjock

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We'll go a bit "sideways" now,

Gene (aka mrvette) asked a few good questions about how the inboard brakes, would mount, etc. Ive takes a few pics of the dry-fitting exercise which may help clarify the approach.

First - a better pic of a Jag IRS:
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Note - it still uses the half shaft as a key component of the suspension.

This image sort of zooms-in on the brake and caliper:
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That sort of shows the approach I want to execute and it would require something like the spreader bar seen in this rear end from a Formula 600/1000:
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I've got a set of 4 of these to mount to the calipers:
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I'll sandwich a stick of 1/2x1/2 steel tube and that will form the struts to the upper and lower supports seen in the following pics:

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You can see here the brake rotors will be just inside the subframe:
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(I wish I could say I planned it that way...) :eek:

In this one you can see the cantilever attachment to the rearmost cross member - in lieu of the typical attachment for the differential:
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Hope those help clarify the differential mounting and integration of the inboard brakes!

Everyone have a Happy New Year! :trumpet::trumpet::trumpet: :beer:

Cheers - Jim
 

phantomjock

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Thanks Mate!
I've stuffed it all in the garage for our winter escape for a few months.
But not to worry, I have a few postings to catch up on. I'll drib & drab them to keep you all entertained and engaged!

Meanwhile everyone have a
:trumpet::trumpet: "Happy New Year!" :drink: :drink:
 

mrvette

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Thanks Mate!
I've stuffed it all in the garage for our winter escape for a few months.
But not to worry, I have a few postings to catch up on. I'll drib & drab them to keep you all entertained and engaged!

Meanwhile everyone have a
:trumpet::trumpet: "Happy New Year!" :drink: :drink:

Happy NY to you too, nice work, where did you say you left that??? :1st::beer:
 
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