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Discussion Starter #22
I cracked open the 6L80 today to get the service number from the controller. It is a TECHM Hydraulic Transmission Controller, service 24256124. This number is important because it identifies through cross reference the engine controllers for which it is compatible.

From the Dorman Products site it shows this transmission controller is compatible with four transmission types, 6L45, 6L50, 6L80, 6L90; also compatible with year models, 2010, 2011, 2012, 2013, and is compatible with fourteen model types from the GMC, Cadillac, and the Chevrolet product lines.

So, I apologize for the misinformation from the earlier post. Looks like my transmission controller is a lot more flexible with year and vehicle models than I was led to believe.
 

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Discussion Starter #23 (Edited)
Change of plan - this C3 goes C6

Hi guys,


It's time for an update!!


A year ago, I thought I knew where this restomod was going. The plan was to use the 496 Vortec, the 6L80, and to upgrade the rear end with new components. The suspension, steering, brakes and literally everything else would be rebuilt. Body and frame modifications for the 496 and the 6L80 would be required. And of course a redesign of the interior.


But over the last year I have given much more thought to the '76, and realize the original build plan to refresh a lot of C3 stuff, just would not work for me. And so I've decided on a new build plan, to build the '76 around C6 suspension components and other C6 and later technologies.


The negative side of this restomod is the extensive work, specifically to the body and frame that must be done. The positive side are the suspension gains that GM engineering bring forward over a 30 year span, 1976 to 2006.


The 496 is still the power plant, that has not changed. But a lot of steel parts will be replaced with lighter components where possible. The heavy truck intake, though it is aluminum will be replaced with a billet/sheet metal, perhaps composite manifold. She will be treated to a dose of Raylar engineering. The heads are here and they are beautiful !


The 6L80 will be rear mounted on the transaxle like the C6 to aid with weight distribution.


First things first, however... A new engine stand will be built for the 496. This special stand will allow the heavy 496 to rotate 360 degrees easily. We'll build it together here at DC, and the plans will be made available to all. Coming very soon.


Please follow along with me through this process.
 

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Good to see you follow through with the 496. One of the things that I have not encountered yet with mine is hood clearance. I have measured and it will be real close but until the body is back on, there is no way to know if there is enough clearance. With that sheet metal intake from Raylar it's going to give you a challenge. The way I look at things there is nothing I can't over come given enough time. I have been working on several projects and hope to get back on the Vette this fall. Ill be following your build very interesting approach using the C6 parts.
 

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This special stand will allow the heavy 496 to rotate 360 degrees easily.
I bought a gear driven stand from Jegs…..or Summitt. I could never seem to get the balance right and wound up working myself to death just rotating the damn thing. Good choice. I'd like to throw the crank away on mine and use a flexplate/ring gear and a very slow starter or something. Lifelong electrician. I can figure something out.
 

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Good to see you follow through with the 496. One of the things that I have not encountered yet with mine is hood clearance. I have measured and it will be real close but until the body is back on, there is no way to know if there is enough clearance. With that sheet metal intake from Raylar it's going to give you a challenge. The way I look at things there is nothing I can't over come given enough time. I have been working on several projects and hope to get back on the Vette this fall. Ill be following your build very interesting approach using the C6 parts.
Speaking of 496, How's your 76 doing these days?
 

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Discussion Starter #29
Marks76, Brent, 1963SS, thanks for the comments.


Ambitious yes, and perhaps a bit overwhelming too. I've never taken on an auto project of this magnitude, so we'll see where this project goes.



The chassis: I am really excited to make this chassis conversion. This conversion is not about increasing value, but more about improving the cars ride, feel, driving experience, whatever you want to call it. I don't want this car to drive or ride as poorly as it did in '76. I don't want the crappy seats, scorching hot floor boards, or the awful air conditioning. So I'm trying to bring improved engineering and technology to one of the most beautiful Corvette body styles built.



The engine stand: All the material for the engine stand is in the shop and has been cut. There are a couple of plates that require machining. I'll get that done next week when I'm home. Most engine stands are configured with a pipe in a sleeve that is welded to a plate with arms that mount to the bellhousing. The unfortunate part of this configuration is that the mount plate rotational axis is near the crankshaft rotation axis. This stand places most of the engine weight above the rotational axis of the stand, making it quite difficult as 1963SS points out to roll the engine. So I've built a mounting plate that allow the repositioning of the engine on the stand, thus moving the center of gravity of the engine to a more favorable position. My stand with geared assembly, if balanced properly one should be able to easily rotate the engine with a 'speed wrench and socket, or with a 3/8" cordless drill motor and socket. The geared assembly has an internal lock so when the drive socket is removed the drive shaft locks. No magic here. I've seen variation of what I'm trying to build out there on the wild internet...


The transmission: Maniacmechanic1 and autowiz posted their comments about the 6L80. Their comments are correct. Perhaps the best choice for the 496 is the 4L80 transmission. But I don't like the 4L class transmissions; I've had a number of them over the years with varied success. Because the 6L80 is a little marginal for the 496, I am now looking into a 6L90 or an 8L90. Either can handle the 496 given my style of driving. Thanks Maniacmechanic1 and autowiz for your comments.


Thanks all again for your comments and valuable information.
Pictures coming, as soon as I get posting procedures down!!



BillT
 

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Speaking of 496, How's your 76 doing these days?
I haven't touched it in 2 years, took a long break:huh: i have however restored a pontoon boat and completed it last week so it's not like I have been sitting around. I am however about out of projects and am getting the itch to start back on the vette. :D
 

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Vetteman,
At the local Moultrie Automotive Swap Meet twice a year, there is a guy that has complete rolling c6 suspensions for sale. It always looks inviting to me to put a c3 body on that suspension. But he also has custom frames there built to combine both. Really nice quality too.

Here's a link, if you're close at the time it's a great weekend hunt too.


http://www.moultrieswapmeet.com
 

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I haven't touched it in 2 years, took a long break:huh: i have however restored a pontoon boat and completed it last week so it's not like I have been sitting around. I am however about out of projects and am getting the itch to start back on the vette. :D
I will keep an eye out for updates on your thread. :thumbsup: That is such an awesome project you have.
 

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Discussion Starter #33 (Edited)
slofut- It would be interesting to see a complete C6 rolling chassis. Wish I had the bucks to invest in a system like that. Sure would save a lot of time on a build. Perhaps I can get to the event sometime soon.


So this is my first shot at posting some kind of photo. If it works, Great. If not - well, we'll try again.


Just a couple of screen shots of the engine stand from my 3D program. One in perspective view. The other just a side view. The side view indicate where the engine mount rotational center is raised up above the crankshaft centerline. This should distribute the weight a little more evenly and provide an easier rotational effort.
The base is large, as the stand will fill multiple roles. It will be modified later to act as a test stand; where the engine will be mated to the transmission and tested together.




 

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Vetteman,
At the local Moultrie Automotive Swap Meet twice a year, there is a guy that has complete rolling c6 suspensions for sale. It always looks inviting to me to put a c3 body on that suspension. But he also has custom frames there built to combine both. Really nice quality too.
slofut- It would be interesting to see a complete C6 rolling chassis. Wish I had the bucks to invest in a system like that. Sure would save a lot of time on a build. Perhaps I can get to the event sometime soon.

https://www.digitalcorvettes.com/forums/showthread.php?t=278842

We got that frame and a few others here:
https://www.streetshopinc.com/

The c5,c6,c7 rear suspension has upper a-arms and the rear frame rails need to tuck in the same as for a back half chassis car. This means modifications to the floors in the rear they gotta be raised. Not the end of the world but definitely food for thought.
 

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Discussion Starter #35
Yep, saw that one coming. The rear deck will have to be raised. And I'm sure the boxes behind the seats are gone too. I'm just worried that the bellhousing for the transmission will wind up being my right arm rest
 

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Discussion Starter #36
Just adding a few photos today


This is a simple photo of C6 - Z51 front and rear suspension cradles sitting on the bench, looking top down. You can find cradle assemblies from a number of yards across the country. You will find varying prices for them. Some vendors do a better job of cleaning and packaging, some, not so much. Some vendors offer free shipping included and others require freight.


My front cradle assembly came from Florida, it was cleaned well, and I paid freight. The rear cradle assembly came from Michigan, it was kinda' dirty but shipping included. In the end all the parts cleaned up well and free of damage.











This photo is the front cradle with the upper frame rails attached. The view is from the rear looking forward. You can easily see the cradle mounting perch points on the driver side, and you can see the frame front and rear attach points. Each cradle perch is cast and machined to a specific dimension. Likewise, the frame attach weldments are jigged and welded in place during the frame build to specific dimension. When the cradle and the frame are mated together on the line there are no shims required.












This photo is of the cradle and frame rail, passenger side, forward looking right. At the bottom of the photo you can clearly see the lower control arm mounting bolts. Directly above you can see the upper control arm mounting pockets. And between them you can see the upper shock mount pocket. The Upper and lower control arms, and the knuckle are cast aluminum or magnesium and machined to a specific dimension. And when they are assembled together with the cradle and the upper frame rail, they form the desired geometry for the corvette. And this design and assembly method is so good, rarely after assembly is extensive alignment required.
Yes, the bonding epoxy can be broken off, but I'm sure it won't be a lot of fun.


 

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Discussion Starter #38
CAN BUS? What does this have to do with a C3?

I've wanted to update this thread for a while, but other distractions have taken priority.


Earlier this spring electrical problems popped up in my 2007 Yukon Denali. I won't bore you with ALL the details but I will share with you the problems encountered, and the Root Cause.


Randomly while driving and often all together, the electronic chime would go off, the door locks would cycle unlock/lock, unlock/lock, the traction control system would disable/re-enable, the transmission would go into 'limp-home' mode. And the cherry on the top, sometimes after parking the car the VATS system would completely disabled the start circuit, giving an indication of a dead battery. This happened, rain or shine, not specifically related to water intrusion.


I finally realized the commonality to all this was the CAN BUS. So I inspected the wiring and found the CAN BUS twisted pair chaffed, specifically at the transmission TECHM plug.





Over time the TECHM bundle plastic loom cover disintegrated and broke away, leaving the wires unprotected. With the loom covering gone, the unprotected wires would occasionally lay against the transmission heat shield. The shields job is to minimize heat migration from the exhaust system to the transmission and nearby components. But with the CAN BUS pair covering unprotected, partially melted, and the BUS intermittingly grounding, the Body Control Module was not able to deal with the broken data stream.


In the end the solution was simple. Repair the wires, replace the broken loom sleeve, and the electrical problems would magically disappear. And it worked!!


A C6 electrical system have been planned for this restomod from the beginning. The electrical problem with the Denali provide me with a better understanding of CAN BUS systems in general, and how the sensors and modules relate to one another.



I guess one could say, this has been a 'blessing in disguise', as I have been gathering a lot of C6 electronics over the last few months.


More to come...
 

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Discussion Starter #39
12/01/2019 Disassembly begins - First day of the Teardown

Today, I started the teardown of the Corvette. As I pulled the carpet away I realized how severely rusted both floor pans are. I got most of the interior apart and after I got the seats out, I found a little rust hole near the driver seat belt retractor. The rust hole confirms the floor pans will have to be replaced. I'm sure more rust holes will show up as I get further along dismantling and cleaning.


The driver seat belt retractor bolt is severely rusted and I can't get it out. But since a color change is planned the retractors can be discarded with the floor pans. I'll just leave it where it is.


Tomorrow I'll have the dash out and the eight body bolts loosened. And from there I'll move forward to break loose the electrical, brakes, head light assemblies, and the front and rear bumpers.


My goal is to have the body off by the end of the week. We'll see if this can happen.















This photo shows the small rust hole at the 5-oclock position just below the retractor.



 

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Discussion Starter #40
An update.

I signed off the last post by saying the body would be off the following week. Well, stuff happens in life; the Corvette project was put on the back burner. While I was unable to put labor into the Vette, progress was made elsewhere. I’ve been busy spending money out on the net gathering parts. And some days were spent in the shop on CAD, measuring and documenting the work ahead.

Here is a partial list of my purchases made since last post.

Electronics: C6 E38 ECM, C6 Body Control Unit with Fuse Block, engine control harness, in dash wiring harness, and a C6 instrument cluster.

Body/Interior: C6 side mirrors and a pristine pair of C6 seats.

Wheels: Rear only so far, a pair of 19x10 OEM Twin Spoke Corvette Alloy Wheels

Engine: 58x reluctor wheel and 4x cam sensor to play nice with the E38 ECM. Oh, I forgot to mention that I did grab a set of Raylar aluminum heads before his latest price increase.

Closing thoughts:
I have delayed the engine build and the engine stand build that I promised a while back. The simple reason, it’s way early to get involved with the engine side of the project. My focus has to remain to get the body off, the frame stripped, cleaned and jigged up to a frame stand. And from there to get the C6 suspension fitted to the existing frame. This will be quite the undertaking. I will post photos soon.
 
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