Goodbye sunroof

[Steve Parmley]

I am about to replace my roof on the "green" 73 240Z because I can't stand another day with the sunroof. I am trying to find someone who has actually done this for advice. I have seen the whole top chopped off and another rewelded on. I already have a donor roof. It looks to me like I may be able to just drill out the spot welds, cut the outer skin at the pillars, and the roof skin would come off. Am I dreamin'?

"Too much sun in California" Steve

[Ed]

I've never actually done a roof but I have seen it done. I guess my advise would be: Measure twice cut once.:classic:

[2ManyZs]

I think a complete roof transplant would be best left to the pro's with the equipment to do the job right. Not that I doubt your abilities, but without the roof the complete unibody is going to lose all it structural integrity. Not too mention the problems associated with re-aligning the roof panel with the drip rail, windshield header, and hatch header when you go to re-weld it in place....

It would be a tough job to say the least. All the hidden spot welds around the windshield and the hatch header panel? UGH!

I think the best approach would be to use the old roof to create just a patch panel for the cut out area of the sunroof and butt weld it in. With a little work, it could be done so that it would be hard to spot. Lay the old roof over the existing one, and cut out your patch by tracing it onto the old one from inside, and leave a bit extra when you cut it out so you have something to work with. By tracing it out, you would be able to have the proper curve in the patch to match up with your existing roof.

I know that this would be one job I wouldn't attempt, especially on a car as nice as the one you are working on.

[Steve Parmley]

The alignment of a complete roof chop is way beyond me. I think I will try removing the "skin" off the donor car roof by drilling all the spot welds. If there are many hidden attachment points then your plan sounds good. P.S. low resolution digital cameras make cars look better in cyberspace than in reality.

[ZmeFly]

honestly to make the job right and to have the car right again a good donor roof is necessary. you will never get the roof right again without loads of bondo or the like.

i had inquired at several shops about this becase of a good deal on a 240 with a sunroof. i was told either buy one without a sunroof or transplant. the idea i had with welding a piece in and fix to make it look good does work but.

what happens is welding and heat take out more of what having a sunroof in the car already did.. i was told it could never really be right not matter how good it does look.

james

[2ManyZs]

I've seen more than one race car with a patch welded into the sunroof opening. Some look like hell, and a few were done so well, you couldn't tell until you looked inside and saw the inside that wasn't finished.

It all depends on who does the welding. I'd check with some specialty resto shops, they usually attract the best welders and body men. It would be worth the extra money to save the aggravation of a crappy job.

[Mr Camouflage]

Originally posted by 2ManyZs

It all depends on who does the welding. I'd check with some specialty resto shops, they usually attract the best welders and body men. It would be worth the extra money to save the aggravation of a crappy job.

Ditto.

Take it to a vintage car restorer, not a smash repairer.

A good vintage repair shop could fabricate and weld in a piece of metal to fill the sunroof hole and you would never even know that it was there in the first place. They may even cut the patch out of the doner roof, so they dont have to shape a piece of metal first.

Removing the whole roof seems a little extreme.

[EScanlon]

I wouldn't remove the complete roof from either car to just do a sunroof hole fill. Not only are you liable to bend the donor roof, you're also making a volcano out of a molehill.

When we did this kind of repair at the body shop I worked at, what we would do is take very careful measurements along diagonal lines drawn from key points on the "receiving" car. This in essence gets you the exact X-Y coordinates of your "grid". Now you know the exact location of the hole. This is so you can match curvatures.

You then transfer the diagonal lines to the "donor" car, and mark off the area on the donor roof that corresponds to the hole in the receiving car. Don't use a drill to make holes yet, you're just marking at this point. Once you've traced out the "plug" you very carefully measure out from the plug another half inch or so. The amount depends on the amount of throat that your edging tool has.

An edging tool is what is used when patching sheet metal, it puts a "step" on the metal. That step is used as a stop for the new metal to align to AND to leave a small gap where you lay your bead of weld. The width of the step is determined by the depth of the throat of the tool, and the edge of the metal is used as a guide for the tool.

Now, you have marked out a plug that is both wider and longer than the hole in the car to be filled. Your best bet to cut without distorting this is to use a jig saw with a sharp metal blade and take your time, you don't want to warp the edge of the metal NOR heat it up due to friction. Be careful that you end up with a nice straight edge as that will be used by the edging tool to form the step edge.

Once you've cut out the metal from the donor car, you edge it with the edging tool.

Next you put the plug up into the hole and align all the edges so that you have a nice even step / space all the way around. If you still have your original diagonal line markings, use them to align also. Once aligned, you can either do a series of quick spot welds to hold it in place or you drill holes for pop rivets, or weld clamps. Once done, you can proceed with welding the patch in.

You won't be doing one continuous weld all the way around, you'll be welding in short sections, alternating between sides, and front and rear. The key here is not to over heat the metal such that it warps. The use of a Heat Dam or Sink is a good idea, but that still means short welds and alternate sides.

If you do a good enough job, you shouldn't have to do an additional weld underneath. You can just caulk it with some hard caulk or epoxy.

Doing the roof in this manner, ensures that you match curvatures on the donor car to the receiving car. This is why the body shop will recommend getting a donor car to donate the metal as fabricating this from sheet metal can really be a bear. This is the most critical part of this job. The roof strength is mostly through the drip rails and front and rear edges.

If you feel that this is out of your league, contact a good body shop, tell them you have a donor roof and let them do the work.

2¢

[Steve Parmley]

I have a donor roof and will get an air flanging tool. Love the grid idea. Thanks for all the ideas everyone. Anyone else have any experience or tips before I get in over my head.... roof... over my head... get it.:sick: Sorry, I'm just glad to be getting help.

[livenbad]

I just put in a top to "close the hole". Cut donor top at corner posts making sure the cuts are below the welds. The top skins as you thought, drilling out spot welds. DO NOT cut structure of your car as the top is part of the frame. If you do have to cut your top chain it down in a body shop so chassis will not flex. Good luck.