Re-Skin a GVR4 Roof, has anybody done this before?

[James]

I would do the full swap I think it would benefit you in the long run considering you want to replace anything that may be broken or worn out. Doing a full swap will let you see things that need to be replaced that you normally wouldn't see.

 

[LIV4PSI]

Quoting transparentdsm:
Quoting citymunky:
There should be no cutting involved. I'm no body guy, but I am a Aviation Structural Mechanic and have been for the last 10 years.



how would there be no cutting involved? how would you re-skin the roof without cutting



I believe Citymunky is saying that you grind out all of the welds at the attachment points, not just cut off the skin.

 

[citymunky]

^^ petty much.

Quoting James:
I would do the full swap I think it would benefit you in the long run considering you want to replace anything that may be broken or worn out. Doing a full swap will let you see things that need to be replaced that you normally wouldn't see.



Please read this --> https://www.galantvr4.org/ubbthreads/showflat.php?Number=1040389&page=0&view=&sb=5&o=&fpart=3&vc=1

 

[James]

Trust me I've read every line of your build. I still think the full swap is the better option. Then you still have a useable shell to either keep or sell. Why sacrifice a vr4 for no reason?

 

[citymunky]

No space to keep a shell for a long term. No time to swap parts, I really only get time Friday nights and Saturday nights to work on the car. Starting around 9PM and calling it a night around 2-3AM.

Trust me I could keep them both I would. 832 would be a the stockish, and 1505 would be a stripped shell, bare bones road track car.

 

[Galantvr4559]

I just bought 391/2000 and it doesnt have a sunroof. I almost want to switch all the good from 559/2000 to 391 and ditch the sunroof 559. I wouldnt cut these cars apart. Good luck

 

[James]

So really there's no option here.

Your original options were skin the roof or do a full swap. Doing a full swap isn't an option due to time constraints.... So obviously skinning the roof is the choice to make

 

[citymunky]

No, at first I was thinking about swapping about the parts over. Than I was told I why not swap roofs? I made this thread to see if anybody here done the job before and if so was it more trouble than it was worth, but talking to and reading from people who done the similar swaps it don't seem out of my scope to perform besides the welding.

But I am leading on the switching roofs (practicing drilling out spot welds 1st on the shell)

 

[rdomeck]

I have used two different types of spot weld drill bits....The first and most common is Blaire and like I mentioned in an early post are available at almost any parts house that sell refinishing products. The second and better option if you can find them are the ones made by Wurth.

Being in the aircraft industry you have probably used Wurth products. I need to order some more, but haven't found the old ones yet. When I do I'll post up the part numbers. Wurth is a company that is a tailored to business's so it's kinda hard to by from them as an individual.

Just remember that the welding will take up about 2% of the time you will spend on this task. I like to use Cleko clamps as I'm going along. The 1/8" hole the leave is very minimal and easy to weld up once your welding in the spot welds.

click

The link above shows the front of a 1962 MGA being cut out and replaced by me this week. I was using a crappy time-lapse camera, but should give you an idea.

Like anything else, take your time and it will come out good!

 

[citymunky]

Here are the basic steps I keep being told. Total swap time 10 to 15 hours.


Remove A, B, C Pillar trim.

Cut out front and rear windshield (using an air knife works best). Expect each glass to take between .5-1.5 hours, depending on how well your air knife works (you CAN do it with an Olfa knife, but expect it to take 2 hours or more, per glass). Then clean up remaining urethane adhesive with a razor blade (get rid of as much as possible)

Remove headliner (do it after the glass unless you can shimmy it out the back of the wagon, in most sedans this is not an option, but it might be for you).

Remove moon roof. Probably about 8 10mm bolts and a couple drainage hoses.

Remove roof mouldings/roof rack, and mask off your roof rails and windows.

Look for resistance spot welds, they will be approximately 1/4" in diameter, and probably spaced out every 6 inches or so. Drill them out with a spot weld cutter. Then use a seam-buster to crack the panel bond between the roof skin and roof opening flange (you can use a chisel if you don't have one or can't find one, but you don't want to damage the roof flange).

Remove roof skin, use a 3M (or whatever you want) abrasive wheel to remove existing adhesive and clean it down to bare metal.

Test fit the new roof skin. Make sure it actually fits. Mark where it will sit in relation to everything else.

Sand down the E-coat on the joining surface of the roof skin. Use 3M Panel bond on both the joining surface of the roof skin and the roof opening flange, apply a thin even coat to the whole surface.

Lay the new roof skin in place.

Resistance spot weld the front and back of roof skin (through the adhesive). This is where you run into problems because these machines are EXPENSIVE. Like, anywhere from $5000-50,000. Maybe there's cheap ones out there, but a quick google search didn't yield anything for me.

Seam seal the edges at the joint, allow to dry, they paint roof.

Reinstall front and rear windshields. Check for leaks.

Reinstall interior.

Enjoy.

Keep in mind, some roof skins need to be welded at the sides as well, and I didn't look up the specific procedure for your car, just gave you a general overview of whats involved, to try to deter you from doing it yourself. It's a lot of work, even for someone who knows what they're doing and has the equipment. Also keep in mind that on a unibody vehicle, the roof is a structural piece, along with the windshield, and if installed wrong, serious injury or death may occur (not my fault, I'm telling you not to do this).

 

[89Mirageman]

If you have to remove the sunroof assembly from the donor car before the roof comes off why not transfer the hole to the non sunroof car? In other words, make a paper template from the old roof and transfer/cut the new one? I just don't see the need to swap the entire roof to install a sunroof. Dealers don't go through all that trouble and they warranty theirs.

 

[rdomeck]

Quoting citymunky:
Here are the basic steps I keep being told. Total swap time 10 to 15 hours.

Resistance spot weld the front and back of roof skin (through the adhesive). This is where you run into problems because these machines are EXPENSIVE. Like, anywhere from $5000-50,000. Maybe there's cheap ones out there, but a quick google search didn't yield anything for me.





You do not weld through the adhesive....It is solvent based and will catch on fire....Not to mention you will not get a good weld. You will have a bunch of holes were the old spot welds were drilled out. These holes will need to be welded through once the skin is attached to the car it's going on. You mig weld through that hole and fill it in.

I'm in the process of doing this on one of the cars in my shop (62 MGA mentioned earlier). I'll get some pictures posted up soon!

 

[citymunky]

I just copied and pasted that.

I talking to the owner of my local auto enthusiast body shop who I did business with in the past. He told me the same thing did, don't weld through the adhesive if I use 3M Auto bond.

 

[misterfixit]

Quoting 89Mirageman:
If you have to remove the sunroof assembly from the donor car before the roof comes off why not transfer the hole to the non "sunroof car? In other words, make a paper template from the old roof and transfer/cut the new one? I just don't see the need to swap the entire roof to install a sunroof. Dealers don't go through all that trouble and they warranty theirs.



Because the roof support structure underneath is different. Also the lole will need to be rolled in with a wall between 0.5" to 1" deep depending on where around the perimeter it is. This is critical to get the roof to seal.

Rich

 

[89Mirageman]

Hmm, did not know that. So how do Dealers install a sunroof then?

 

[turbowop]

Cut and hack. That's why aftermarket sunroofs are not liked. They have issues and tend to leak, whereas the OE ones are great...for the most part anyway.

 

[citymunky]

Thanks to this EVO 6 buid thread click I have a better idea how to swap the roof skin.

Quote:
Now the engine is in I thought I'd celebrate by fitting the carbon roof

Obviously the interior trim had been removed, so fitment was really straight forward.

Tools required for anyone that might want to attempt it;

Drill, Air or Electric
8mm spotweld removing drill bit
Hammer and small chiesel
Scraper
Cleco skin pins
Cleco pliers
Knife
Ruler
Clamps
Deburrer
Rivet pliers
Structural adhesive
Adhesive primer
Masking tape

Think that's it, now for the job itself

All the spot welds around the perimeter of the roof need to be drilled off, drill just through the roof skin, not any further, this is where good judgement is needed as you don't want to drill into and weaken the metal below.

After all the welds have been removed, cut through the sealant around the roof on the outside and on the inside and then very carefully split the roof away from the structure using the chiesel if needed to break any metal that is hanging on around the welds. You may need to drill some of the welds a bit more until they come apart.

Once the roof is free of all welds you can carefully lift it off, you may need to cut away any sealant that may be hanging on for grim death

 

[citymunky]

Since he is installing a New uncut Carbon Fiber roof, there are extra steps here but i'm posting them anyway.

Quote:
Next you need to carefully grind away any raised spotwelds that are left on the structure, and remove any sealant that will stop the new roof from seating properly.

After that lay on the new carbon roof and apply masking tape around the rim, to protect the roof and to allow marking out where you'll drill for the rivets.

Use clamps forward and aft and a ruler to get the roof sitting completely in the middle, left to right. Once it's ok, mark the masking tape and take a measurment and remember it.

Remove the clamps and lay on the front and rear screen to get the forward/aft position correct. Once marked on the tape, remove the screens.

Clamp the roof so it lines up with the markings that you previously made, and then mark around the perimeter where you're going to fit the rivets. I fitted a 5/32 rivet every 5".

Then drill a hole either side in the b-pillar area and secure with a cleco skin pin.

Once you're sure the roof is in exactly the correct position, all the holes can be drilled off, work from center positions outwards, making sure to clamp with cleco skin pins as you go.

Once it's all drilled off, remove all the skin pins, remove the roof and deburr all the holes on the roof and on the structure.

 

[toybreaker]

One lesson I learned the hard way is cleecos + thin carbon panels = potential heartache

Use a fiber washer under the cleeco to prevent cracking/chipping around the holes! A fiber washer will spread the loading out, preventing cracking and done correctly, there won't even be a witness mark.

ymmv

 

[citymunky]

I'm not a fan of the pop rivet idea for a street car without a cage, but I'm just posting it anyway.


Quote:

On deburring, without a cage you can get to the underside of the holes with a normal countersunk bit, but with a cage installed you need to use a tungsten carbide bit in a dremel or similar.

With everything deburred, the mounting surfaces of the roof and structure of the car need to be primed with a special primer which helps the adhesive to stick.

Now for the good part, you need to apply a bead of structural adhesive (I used Dinitrol 501 FC-HM) on the mating surfaces of the structure of the car. I lay a bead around 7mm in diameter, not too much so you'll get excessive residue, but enough to fill any gaps and make the roof water tight.

Then carefully place the roof onto the car, this can be awkward as the roof needs to be placed into the correct position as the adhesive 'grabs' the roof and it's hard to move without messing up the bead.

When in place secure with all the cleco skin pins, clecos are excellent as they clamp the roof all round with the same tension, and so make sure the roof sits evenly.

Next remove one cleco at a time and replace with a 5/32 pop rivet, making sure you coat the rivet shaft with adhesive before install to fully seal the hole. It's a good idea to start in the middle and work evenly around the roof as if you were torquing a head down.