Replacing the roof?

[a7dz]

I would flange the roof and over lap the welds gives you a little more room to adjust the two pieces as necessary to get the roof to lay right. Then weld the donor piece in solid using the stitch welding method. I would ask the guy doing the work his thoughts also.

[xray]

It's not as easy as it looks. Even after pulling dents and waves on my roof, the bodyguy who painted my car and did all my work noted how complex the multi-radiused curvature of the roof is, side to side, fore and aft, etc. Basically, hiding the welding seams is the least of your problems--aligning the curvature is the bigger issue...

If it doesn't match up perfectly it will not look right at all.

The other issue is what lies beneath the sunroof weatherstripping. If it leaks, there is likely some rustiness that may exaggerate the cut-out of the roof, adding to the difficulty of the repair.

I'm not saying it's impossible-- I'm saying that if it were my car, cost associated with the repair would be secondary to quality of work.

[geezer]

It's not as easy as it looks. Even after pulling dents and waves on my roof, the bodyguy who painted my car and did all my work noted how complex the multi-radiused curvature of the roof is, side to side, fore and aft, etc. Basically, hiding the welding seams is the least of your problems--aligning the curvature is the bigger issue...

If it doesn't match up perfectly it will not look right at all.

The other issue is what lies beneath the sunroof weatherstripping. If it leaks, there is likely some rustiness that may exaggerate the cut-out of the roof, adding to the difficulty of the repair.

I'm not saying it's impossible-- I'm saying that if it were my car, cost associated with the repair would be secondary to quality of work.

This is absolutely true, but there are methods to ensure the curvature and concentric dimensions are accurately placed. If you have ever seen roof panels as they arrive from the stamping plant to the assembly plant, they are stacked with nothing in between them in the way of padding or insulation. They retain their shape until removed from the rack and welded on the vehicles, simply because they are stacked identical stampings with strength in numbers. This same principal is used in the case of welding a replacement panel such as this roof in the proper attitude. For a roof such as this, longitudinal strips of a much heavier gauge steel would be used to support the existing roof and filler piece. In this case they would be used on the inside and likewise lateral strips laid and bowed under tension across on the outside. In years past these strips would be bowed and temporarily tack welded into place under enough tension to retain the desired shape. Today the same thing can be done with the use of rare earth magnets to firmly hold the tension strips in position. When the panel is perfectly aligned it can be stitch welded in place. This is just one of the tricks of the trade that a competent body man or fabricator would know of and put to use when needed. Bottom line..ask questions about the methods used by the guy you choose.

[zanthus]

You also have to take into consideration that when your welding your heating the metal that isn't all that thick so you'll have to watch out for metal warping. Go slow and take your time, if you do that and get the curvature correct you should be fine.

[beandip]

Arne , you never saw my roof before my redo. It looked like a bag of potatoes, with all the waves and dents. Butt dents just aft of the windshield on both the driver and passenger side. Now she is ripple free and there is no bondo . EScanlon and I spent a bunch of time with it but it came out vary well. I think geezer is the way I would go. Contact jetjock240 , Roger has a good body guy up here in Hillsboro that does Z cars and has done some great work on his 240.

[BD240Z]

I had a 280Z with a sunroof that I didn't like at all. I found a donor roof from someone local who was parting out their car and then got some quotes from two different shops to weld it in. Both shops wanted to cut the old roof off at the legs and then weld in the replacement. From what I understand, this is the proper way to do it.

I can't remember how much I was quoted but it was high enough that it convinced me to do it myself.

I took the donor roof and cut a piece that overlapped the sunroof hole by one inch all the way around. I took a bunch of measurements to insure I was cutting the metal from the same location on the donor to the corresponding location on the car.

I had a friend spot-weld three one inch wide steel strips that ran the length of the roof to act as a stiffener. I then riveted the replacement panel into place at four points. The replacement panel got attached from the inside of the car. Then the fun began!

With my son bracing the roof from the inside of the car with a block of aluminum, (poor mans heat sink) and gloves, I began to stitch-weld the roof in. In order to keep the heat down and prevent warping, I would weld a 1/2" to 3/4" bead and then stop and then go to the other side of the roof and repeat the process.

We had to stop quite a few times and let the metal cool down because I was afraid of the metal oil canning. It took practically the whole day.

After the welding was done, we ground the welds, did some tapping with some body hammers and then applied our body filler. Getting the roof straight with all the block sanding, guide coating, etc. took about two days total.

When it was done I had the whole car painted and it turned out terrific. It took longer than I thought and was more work than I expected but we had fun. I was glad I didn't pay someone to do the job.

I sold the car to a friend and see the car regularly and it looks just as good now as when we completed the job.

Like all the work required on these cars, I like to do as much as I possibly can, especially since my son is usually involved. Besides, I think I do a better job than most suppliers would do anyway.

Good luck with your efforts.

Bruce

[Arne]

Latest update - I've been in touch with a bodyman in Salem, OR who has re-skinned several S30 roofs. He knows what to do, where to cut, and how to get it all right at the end. His plan is to cut at the top of the windshield opening, the top of the rear hatch opening, and just inboard of the drip rails. The attached picture shows pretty much what he does.

Related question -- Assuming I carefully remove it before hand, any tips on re-gluing the original headliner back into the car after this is done? The headliner now in the yellow car is original, and perfect. I'd love to save it rather than go with a replacement, if possible.

[hls30.com]

Arne,

I think your best bet would be to carefully remove it and remove and replace the foam backing. I have glued several back up, and the 30 plus year old foam always gives up, after being taken down.

Also, the inside of the roof must be spotlessly clean before gluing.

Will

[Carl Beck]

His plan is to cut at the top of the windshield opening, the top of the rear hatch opening, and just inboard of the drip rails. The attached picture shows pretty much what he does.

This is absolutly the ONLY way you ever want to replace the roof panel on a 240-Z. Take it to that man, he knows what he's doing.

FWIW,

Carl B.

[Carl Beck]

Both shops wanted to cut the old roof off at the legs and then weld in the replacement. From what I understand, this is the proper way to do it.

Absolutely NOT. That type of hack job can put a body man in Jail in Florida. Most State's have consumer protection laws that govern how Uni-Body structures have to be repaired. Sadly they aren't enforced very often - but when they are - the Politicians like to make an example of the offender.

You can weld a patch in the hole - or replace the roof skin. Either method will have retain the strength of the original roof panel. When cut through the multiple overlaping layers of sheetmetal in A and C pillars - it's impossible to reweld all the layers cut.. only the external layer can be welded .. .and that is a huge NO NO when it comes to repairing a uni-body car.

You did the right thing - from a structural perspective - by patching the hole.

FWIW,

Carl B.

[Arne]

This is absolutly the ONLY way you ever want to replace the roof panel on a 240-Z. Take it to that man, he knows what he's doing.

FWIW,

Carl B.

My thoughts exactly, Carl. It made so much sense when he explained it to me, compared to what other people were talking about. I plan to call to discuss his schedule tomorrow.

[240dkw]

Arne: I have a sun roof that I want to replace as well, photos of the work as it is being done would be great. Here is a web page I found showing the way I think I will try with my car. http://members.tripod.com/trueweb/Zcar/ About half way down the page there are a couple of good photos of the roof replacment.

Dan