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Old 01-12-2019, 09:09 PM   #46
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Vintage Air Installation in a late model C3

Back at it again! The leukemia has finally decided to get off my ass, in remission, last year was a rough ride! Anyway, I decided to try to post in real time my experiences with the Vintage Air Sure Fit kit designed for 74-76 C3. I think there are a couple of other posts on the subject but I figure additional info can't hurt. Went with VA and removed all of the OEM stuff. Believe it or not, the AC actually was working when I took it apart! I bought a brand new 1982 C3 in 1982 and the stock AC was pretty marginal, even under the best of conditions. Accordingly, I couldn't see throwing a bunch of money into the original system. BTW I have all the OEM parts I took off should anyone on this forum needs any original parts. Will sell for a very reasonable price. Will probably post in the for sale part of this forum. Everything is original, even the heater core looks to be in excellent condition. It has all been stored indoors.

Got the underside/engine bay prepped and painted. Also cleaned up the notoriously ugly cowl area where the wipers rest. Those always look like someone with a 4" brush and bucket of tar slopped the goo everywhere! It's ugly and unnecessary. I scraped out all that beige colored seam sealer and reapplied a more reasonable bead of body sealant along the joint. Also resealed several of the joints around the windshield frame. They aren't in the picture but the wiper mounts are also completely cleaned and refinished in satin black.

Like I said, I'm trying to do this in real time for a change, I'll post progress (or failures) as they occur!












Here's another pic of the underside. Note the missing driver side floor pan. More on that later...





I originally had planned to just buy several of the components that came with the 74-74 Sure Fit kit, but after talking to the VA folks I decided it would be better to just customize the kit. There are several parts that I won't use, but there are several other components that will make this MUCH easier. VA also deleted the controls for the 74-76 and I selected a universal 3 knob controller. They also built the kit with the universal ECM. Here is the Gen-4 evaporator case and all the stuff that comes with the kit.






Front side....





The pre bent plumbing is a real time saver and probably worth the price of admission by themselves. I have some pretty good tube benders but I can't make bends this tight and close together.





The kit also has this neat bulkhead for the plumbing to go through.





The fresh air duct is blocked off by this plug from the kit. The firewall blockoff plate is also installed. The original blower "hole" is blocked off by another furnished plate that will show up in a later photo.






Next, I drilled 2 new holes in the firewall using the templates provided. This is also where I discovered the first discrepancy. There is an original 3/8" hole in the firewall that doesn't look to be in the same position as the 74-76 C3. There is a 1/4 x 20 bolt that goes in from the engine side and threads into the evaporator mount. Before I drill a new hole I'm going to have an extra set of hands over here
tomorrow and test fit the evaporator.






And here's the view from the engine side. Here you can see the round blower motor blockoff plate that came in the kit.




The body is completely disassembled at this point making access, and photos, a lot easier. Oh, remember the missing driver side floor pan? Earlier in this thread I detailed the problem of the driver side floor pan being a good 3 to 4 inches lower than the passenger side. That's due to the driver side power seat. But that increased depth seriously complicates running a custom exhaust system. So, I had seen a few late model C3's that had seats from a C6 installed. The C6 seats have a much more compact motor drive system and do not require the deeper floor pan, although you do have to fabricate a mount. I have the C6 seats and have already test fit them. They are a little tall but I think they will work just fine. I have the new floorpan for a non power driver seat but haven't installed it yet because of an unintended benefit: With that big hole in the floor, I can just raise the body and literally stand up inside the car! This makes all the under dashboard work, like hanging the pedals and roughing in the wiring harnesses, light years easier than contorting yourself under the dash. That is a seriously great benefit for us old timers! So once the majority of under dash fitting is done I'll weld in the new pan.











More to come, that's as far as I got today...
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Old 01-13-2019, 10:00 PM   #47
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The mission today was to determine the location of the 3/8" hole in the firewall. The 81 factory location for this particular hole apparently changed slightly from 74-76. My son helped me with locating the evap box in a position that was level (for proper condensate drainage) and also did not rub against anything. It's a 2 person job, one on the inside to support the evap box and mark the hole C/L while the other is on the engine bay side to ensure the plumbing exits in the center of the big pass through hole. Spent quite a while being sure. Finally decided it couldn't get any better so I marked the spot to drill. In my experience drill bits, especially larger ones like 3/8", can often drift thus changing the location of the hole. I drill a smaller hole first (1/8" or so) then chuck up the 3/8" drill bit. It's foolproof to center in the 1/8" hole. On fiberglass I find it best to drill at a high speed with gentle pressure, especially when the bit is nearly through. I am going to draw up a template for this hole location and post the pdf in this thread. It will print at full scale and anyone wanting to use it can just print it then cut out the template. I didn't have time to do that tonight but will get it done. I think it will take a larger paper than 8-1/2 x 11 though.






Below is where the new hole is located on the engine bay side. You can see the OEM hole up and to the left. I'm not crazy about the appearance, would look better if it were centered in the cover plate "notch", but that is where it needs to be. I also had to grind off a little of the washer so it would sit flush on the firewall.





And there it is. Doesn't hit anything anywhere. I left enough room to allow for the Dynamat and insulation like Dynapad or something. As an aside, if you get deep enough into the under dash area, I recommend removing all that factory matting. The newest C3 is 37 years old and that matting will be filthy, stinky, and crumbly.






Below shows the 2 sheet metal screws that secure the cabin side of the evap box. There is a drilling template that comes with the Vintage Air kit, but it will not work on the late model C3's. Near as I can tell, there are differences on the reinforcement brace that is used as a reference for the template. The VA instructions also want you to use one of the existing holes for one of the sheet metal screws, but there are no existing factory holes on the late model C3's, or the 81 model at least.





The view from a little further back.





Engine bay side showing the "modified" washer. The fastener is 1/4 x 20 and the hole is 3/8" which provided a little "wiggle" room. On final installation I'll block off the visible unused hole.






A little different angle...





Below isn't part of the evap install, but since I was right there I got a pic of the hydraulic clutch master cylinder mount and reinforcing plate I built.






Got the pedal cage installed, wanted it there for A/C duct routing. On the upper left of the cage if you look closely you can see the hyd clutch pushrod. It has a Heim joint on it that fits perfectly on the existing pin where the original clutch pushrod attached.





Below is the "cluster" of heater/AC hoses. I was dreading making these so the VA kit made it a piece of cake. There is a bulkhead plate with 4 holes in it To close up the space around the tubes. The holes have grommets to prevent chafing of the tubes.





Dashboard and steering column temporarily installed for duct fitting. The interior color will be changed to Dark Blue. That is a tribute to my 82 that I bought new. The blue is so dark that it almost looks black, that is until you hold something black against it. Then it looks like a dark grey with a hint of blue. If I'm not mistaken I think 82 was the only year that color interior was used.


Oh, and you can pretty much kiss your glove box goodbye! A couple of quick measurements indicates that I might be able to slice off the back of the glove box, then plastic weld a new back on the box. It wouldn't leave much space, maybe just enough to store a pair of gloves??








I'm hoping to be able to use the VA duct that came in the kit. It's smaller which will help in that very congested area, and has the barbed end on it where the flexible duct hose can attach. However, it is slightly thicker right where it passes under the steering column. I don't think that will be a show stopper. It follows the same general shape as the OEM duct so I think it will work. The driver and passenger air registers may require slight modification on the tube end, not sure yet. Also, the driver and passenger registers are identical and have the same part number molded into the plastic.


In the pics below, the VA duct is the one with the foam on one end.














Next will be starting duct fabrication. Kind of "A Ductwork Orange". Those in my age group will get the play on words!
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Old 01-15-2019, 08:56 PM   #48
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Help! ABS plastic kicking my butt

Ok, I'm going to have to use a lifeline here. After doing some eyeball engineering on the duct routing (Vintage Air custom install) it doesn't look like it's going to be anywhere near as hard as I thought. I can see exactly what "cuts and joins" need to be made in all those ABS plastic ducts.


I'm reasonably proficient at stick, MIG and TIG so after reading about ABS "welding" I thought it would be a piece of cake. I ordered up one of those hot air guns and an assortment of plastic "welding" rods.


Went to the junkpile and gathered up some junk ducts to practice on. The hot air gun is useless. The tip where the hot air blows out is about 1/4" in dia. It's WAY WAY too big! Even though the temp is adjustable the fan speed is not, and it just hits the ABS like a blast furnace melting an area the size of a half dollar before you can even raise an eyebrow. For this to work I think the blast of hot air should be very small and low velocity. Ductwork 1, John 0.


Next I dug out an old Weller soldering gun, one of those things that has a tip made of square copper wire. The trigger has a hot and really hot detent. Short story is that the tip is still way too big, and surprisingly didn't really seem to get as hot as I would like. So when mooshing the tip around in the melted ABS while trying to add additional plastic rod resulted in a horrific looking glob with questionable penetration. Ductwork 2, John 0.


Next I tried my Weller WES51 soldering station. Put a small tip on it, and dialed up the temp. It has a thermocouple controlled tip for precision soldering so I could dial up and maintain a consistent temperature. This was the closest I came to success, but somehow even though the ABS melts, it doesn't want to flow together like you would think. You have to push it around with the tip of the soldering iron while adding material at the same time. The result was a hideous "bead" and it had little strength. I was able to break it apart with very little effort. Ductwork 3, John 0.


Vintage Air sells a bottle of the adhesive they use to assemble the ducts. It looks like they staple the pieces together then run a bead of this adhesive along the joint. It is a very hard and shiny appearance, far better than anything I could do with heat.



Very frustrating (and humbling) because if it was metal I could TIG it up in nothing flat! I'm dead in the water until I get this figured out.



Does anyone have any advice or guidance for welding together ABS plastic? Anyone have any idea what the proper chemical adhesive might be? I'm guessing it's a solvent based chemical that "burns" into the plastic but I don't know for sure.
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Old 01-16-2019, 10:07 AM   #49
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Plumbers use ABS cement to connect the ABS pipe together, perhaps this would work?

https://www.homedepot.com/p/Oatey-8-...8893/100345366
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Old 01-16-2019, 08:48 PM   #50
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ABS Problem solved

Ok had a much better day today. Turns out I was taking a pretty simple process and making it a hundred times more complicated.


7TRoadster I'm pretty sure that plumbers ABS adhesive would work.


I kept seeing the term "weld" associated with plastic and somehow that gave me tunnel vision. I was trying to make a pool of molten plastic like when you weld metal. That won't happen with ABS. This morning it dawned on me that a solvent that chemically melts into the plastic then evaporates is what I need, just like when we used to build plastic models. A quick google and I learned that the best solvent for ABS is acetone or MEK.



I have both on hand, but my background in aircraft maintenance taught me that MEK is some pretty bad stuff so I only use it when nothing else will work. Of course acetone is pretty nasty too! Did a quick butt joint using a Q-tip to dispense the acetone along the joint, both sides. Also did a lap joint. Butt joints are never all that strong but the bond here was pretty good. Far better than any heat based weld I did. On the lap joint the plastic failed when forcing apart leaving the joint intact.








Be sure and remove the diffuser, they usually fall out anyway. But if you drip some acetone onto it you will have a permanently rigid diffuser. Don't drop it either, they are amazingly fragile.





So, here are the parts we are going to be working with. This is for the driver side AC register.





It turns out that the adapter "cone" from VA is almost exactly the right size to just slip over the OEM duct. The small end of the cone fits into the VA duct, nice tight fit into the foam.





The OEM duct is too long. After a little eyeball engineering I concluded that the duct needed to have 2-1/2" removed. The end needs to remain perpendicular to the axis of the duct. Mark and cut carefully.





The cones came with 3 squares of velcro glued into the cone. These need to be removed.





Carefully sand or grind a slight chamfer on the OEM duct. Also use a Dremel sanding drum (or equivalent) to put an internal chamfer on big end of the cone.





The cone should now just slip over the duct. Again, try to keep the cone perpendicular to the axis of the duct. My bench is level so I just propped the duct on a couple of old 3" gauge blocks then checked the level both north/south and east/west. It's not a critical measurement but if it's too far off it might affect the final fit.





Using a Q-tip, sparingly dab the overlap joint on both the inside and outside of the joint. Acetone is very thin so don't get too crazy with it. It will wick into the joint almost instantly. Take your time and be careful not to get the acetone all over the place. Here is the inside of the cone after the acetone has been applied. Remember, less is more in this case!





And here is the outside of the cone/duct joint.





Here is the finished duct. This will fit right into the register "hole" in the dashboard and will cross under the steering column. The other end will now be in range (about 10-12 inches) to the evap output duct and can be connected using the VA flex duct. I still need to fabricate a support of some kind to keep it in place. The space saved behind the register under the dashboard is significant, this is a VERY crowded space with the fuse block, hood release, etc.





Next up: Defrost and center registers. These promise to be a little more of a challenge!
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Old 01-16-2019, 09:02 PM   #51
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Just read through your thread. Your build looks very nice. Great attention to detail. Nice documentation also.
Looking forward to more updates.
-brent
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Old 01-16-2019, 10:28 PM   #52
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Using VA templates

All - In reviewing my build thread I noticed something that I failed to mention and should be clarified. The VA instructions come with several templates but I didn't emphasize something.


After the new 3/8" holes are created you have to saw out a chunk of the lower right firewall. If you do this BEFORE you drill the 3/8" holes, you won't be able to use the templates!


It's not a show stopper but would make positioning the evap much more difficult.



I attached the relative page from the instructions and a photo below.





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Old 01-18-2019, 09:18 PM   #53
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Driver side AC duct, part deaux...

After I did all the previous mods to the drivers side AC duct, I installed it temporarily for some measurements. The VA duct is about 1/2" lower than the OEM duct when measuring from the floor up to the duct. I am confident that the extra 1/2" will not be a problem, but after studying it for a while I came up with a "modification to the modification". I can then move the duct a little closer to the driver seat. Since the distance between the floor and the steering column increases as you move toward the drivers seat I thought I might gain a small amount of clearance. On top of that, I believe this second mod is actually easier to do. So here goes:


Here are the completed parts after the first mod.



Begin by hacking off the cone that was installed in the first mod. Cut it right where the OEM duct ends. Don't make the OEM duct any shorter. Here's what it should look like after cutting the cone off.


I couldn't find any ABS tubing that was the right size to slip into the round OEM and VA ducts, so I scrounged up some .0625 black ABS sheet. I cut a strip 10.375" long and 1.250" wide. The strip is pictured below. It's actually black, just some weird lighting effects.



What we are going to do is make a sleeve that fits inside the OEM and VA ducts. To get a curve on the strip I used a heat gun and infrared surface thermometer. Also a can that has a diameter roughly the same as the ID of the ducts. There is quite a bit of leeway on that diameter, it isn't critical. We just want some curvature to make the strip easier to install. Put a diffuser on the heat gun and always keep it moving. I'm not sure how accurate the reading of my thermometer is, plus having to work quickly, but it seemed like the ABS started getting soft somewhere around 230. Go easy here, it doesn't take much to ruin the strip. Wear gloves, and when the strip just begins to get soft, quickly wrap it around the can. It will cool in just seconds. Just keep heating and working with it until it is reasonably round. It's a lot harder to describe it than it is to do it.



Insert the new "ring" into the VA duct. The ends will overlap so mark where the excess is and trim the length of the ring so that they just butt together when inside the duct. Cut the strip at the marked location. You might have to play with it a bit to get it just right.





When the ring fits properly inside the duct, cut a small piece of ABS about 1" x 1.250". Heat it and press against the can so that the arc will match the ring. Try to get it pretty close. When you are satisfied with the fit, remove the ring from the duct. Join the ends of the ring and hold in place with some gorilla duct tape or equivalent. Then dab some acetone on each end of the ring (on the inside) and press the small curved chunk of ABS across the joint. Clamp for a few minutes and you should wind up with ring that will act as a union. Do not try to glue the ring while it is installed in the duct! Acetone is so runny that it will quickly seep through the butt ends of the ring and you will probably not be able to remove it.


So here are the components for the modified mod.









And here's the end result. I think this is the shortest length between the OEM register and the back of the VA duct that can be obtained without creating a whole new duct from scratch. I've thought about doing that but I would like to get this project finished at some point!




And here's what they look like installed. The photo angle is from about where your butt would be. The first photo is the OEM duct, while the second photo is the VA duct.






That's about the best I can come up with for maximizing floor clearance. If anyone has any ideas on this duct feel free to share! Like I said, I'm pretty sure it will be ok. The newer and shinier VA duct makes it look bigger than the OEM duct but they really aren't that much different in the clearance dept.
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Old 01-19-2019, 09:49 PM   #54
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Quote:
Originally Posted by zimmej51 View Post
.

Does anyone have any advice or guidance for welding together ABS plastic? Anyone have any idea what the proper chemical adhesive might be? I'm guessing it's a solvent based chemical that "burns" into the plastic but I don't know for sure.
Plastic welding, yes solder iron method works ok. There are a few others but try looking up friction welding on youtube. You said you already have some plastic welding rods which I'm guessing is 1/8" diameter. Slide some in a dremel, bevel your material edges and have at it. The dremel will friction weld the 2 pieces together while melting the rod. Go back and forth or circles like real welding. I did this to my gto intake setup on my ls3 swap. I hope this helps, glue route may be easier too.
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Old 01-19-2019, 10:08 PM   #55
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Thanks Blueday, using the Dremel is a good idea, I'll give it a try soon, I'm certain I'll be having to join more plastic pretty soon.
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Old 01-19-2019, 11:08 PM   #56
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Mounting driver side VA duct

Didn't get a whole lot done today, my goal was to get the modified VA AC duct installed today. I taped it in place so that I could figure out the best way to mount it. I was the most concerned with how to attach the duct on the end opposite the register end. There are probably 9 different ways to accomplish this, but I decided on the method below. I wanted something that would securely support the duct, be easily removable, and would not interfere with the collapsible steering column. I wound up using one of the 4 carriage bolts that support the steering column mount. Turned out like this. Used some poster board to make a template for a bracket. Once I got the paper trimmed and folded to suit me I converted it into metal. I used some 18 gage steel plate I had laying around.








Next, I repositioned the duct and tweaked the bracket until it lined up with the duct the way I wanted. I marked the duct where the hole in the bracket contacted the duct. then I added a reinforcement plate inside the duct where the mounting hole was going to be. It was about an inch square. I heated it with the heat gun until it was pliable enough to conform with the internal shape of the duct. Then I wetted the area inside the duct with small quantity of acetone. I quickly inserted the reinforcement and held it in place for 30 seconds or so. A little hard to take a picture of it.





I like to use "rivet nuts" for applications like this and I had a bunch left over from the fuel line project earlier. I drilled a hole using a size "L" drill bit through through the duct and reinforcement. Below is the Marson Threadsetter along with a 10-32 rivet nut. It works similar to a pop rivet gun except it doesn't "snap" when the rivet expands. You have to unscrew the mandrel. When finished, they provide a very clean and strong steel insert.




Here is the duct with the rivet nut installed, and a 10-32 stainless button head screw.




It's a little hard to see, but the new bracket is at center of the picture.











And this is what it looks like installed. As I mentioned, there are any number of methods that probably could be used. The bracket is quick and easy to build, strong, and doesn't interfere with anything that I know of. I also attached a quick drawing of the bracket. The dimensions are not critical but if anyone is contemplating a VA in a late model C3 this bracket will get you started.





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Old 01-20-2019, 02:32 AM   #57
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Thanks for posting and glad you got back your health
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Old 01-21-2019, 09:50 PM   #58
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Thanks, it's great to be back!
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Old 01-21-2019, 10:23 PM   #59
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Vintage Air duct work

Ok, moving forward with duct modification. The driver side appeared to be the most difficult so that was the one I started with. Even though my first iteration of the duct mods (detailed earlier in this thread) probably would have worked, I went ahead with another mod to the existing mod. I was striving to get the duct as far towards the driver as I could. That's what drove my decision to cut even more off of the duct. It fit a lot better and helped improve the limited space under the drivers side of the dashboard.


Even though the shortening greatly improves the fit of the duct, a side effect is that the duct will not stay on the dashboard register. Before, it was long enough that the duct, along with the attached foam, created a tight enough fit to keep the duct in place.


So I had to figure out a way to mechanically attach the duct to the register. Plus, the attachment device had to be accessible from under the dash after everything is reassembled. I finally decided on a simple "bail" made from 0.078 (2mm) music wire. The ends of the bail would poke through holes drilled through the register mount and the duct.



Another thing I learned is that the two 7mm (per register) are incredibly hard to get to, so If you ever get this far into the dashboard I recommend installing the register frames BEFORE you reinstall the dashboard.



Here is the duct with all the mods completed.



Here is what the music wire "bail" looks like.



And here's what the duct/dashboard looks like with the attachment clip attached.





And a seldom seen view of the engine side of the dashboard. The clip is very easy to remove/install yet holds the duct securely.
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Old 01-22-2019, 09:23 PM   #60
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Defroster Duct

Moving on to the defroster duct. In the 74-76 kit from VA, a defroster duct is included. On the 74-76 the duct is retained by a screw at each end. But the defrost opening on the 81 is a little different. It's not quite as long and has no attachment points for the duct.


But the good news is that it's pretty close. Oh, and ignore the gold appearance. That's just some weird lighting effect. The duct is black ABS.








I trimmed away the foam stuff around the dash defrost opening and taped the duct in place using Gorilla duct tape.



With the defrost duct temporarily taped in place, I snapped the dash back into position to check for clearances. Fits perfectly with plenty of room all around, and it's just a short run of flexible duct from the defrost duct to the evap case.


I think I'll just permanently attach the duct to the dash, probably just make some tabs from ABS and glue them to the duct and dash. It's a lot more work to adapt some kind of fasteners to hold the duct in place. Besides, if I ever need to do something to the duct the entire dash will have to come out anyway. There is virtually no way anyone could reach the fasteners with the dash installed.
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