How to cover slits in Aceca roof

[Vincent998]

I need some advice about Aceca restoration, and hope I can find it here. Before stripping the body, there were indications in the paint that something was amiss above the rain gutters. After stripping the body, it was clear that there is a slit on each side above the rain gutter. The slit extends from the A pillar to the end of the rear quarter window. The alloy roof is carefully and evenly nailed with brads to the inside wood of the roof frame along both sides of the slit. At some point in the past, someone tried to solve this by applying fiberglass tape to at least part of the slit, but that did not last. I've attached photos of the slit. Apparently this was factory practice; I have been told that other Acecas also have this slit, and I have seen photos demonstrating that. My rebuilder and I are trying to decide what to do to ensure that there are no future body or paint problems arising from this method of construction.

My rebuilder thinks that because the slit is backed by wood, there will be enough expansion and contraction due to changes in humidity etc that it will produce cracking or other surface problems that will eventually show. He has suggested temporarily removing the wood framing to free the shell and then welding in a long alloy patch for the length of each slit. I am not so sure that's a good idea.

Here are the questions I would appreciate receiving your opinions about:
1) What did the factory do to cover this area before painting?
2) Has the factory fix worked (that is, has it held up after all these years)?
3) If what the factory did can't be done now or did not hold up, what should be done to cover this area?
4) If you've solved this problem, how did you do it?
5) Is there anything I've overlooked or don't know about this method of construction but should know?

I look forward to hearing from folks who have dealt with this issue, and thanks for your time.

[Aceca289]

There are two types of rain gutter systems on Aceca's. The early type had an extra trim rail running above the gutter that appears to be wide enough to cover the slit shown in your pics. Based on the pics of when my father last had the car painted in 1990 (see pics below), it's evident that the rain gutter was secured to the roof by a series screws spaced about 4" to 6" apart running the length of the gutter. The extra holes in your roof on either side of the slit appear to match up with the extents and alignment of the original gutter arrangement. Looking at the close up pic of the end of my gutter/rail it seems possible that it may have also been glued to the roof rather than welded (based on the lack of deformity of the rail that would have occurred if it was welded in place). This method of attaching the rain gutter may help explain for the bubbling paint I have running along the top edge of my rain gutter trim (see pic). If you look closely at the the bubbling, you can see what appears to be a strip of tape between the rail and the roof (apparently not the best method to close this gap - I'd like to know of a better method for when I go to paint my car again). I assume water got behind the rail and possibly into the wood during wet sanding resulting in the bubbling when the paint was drying/curing in the sun. Could this sort of issue with painting have led AC to change the style of the rain gutter in later cars?

It appears AC did away with the extra wide gutter/trim arrangement sometime in 1958 and went to a single gutter arrangement that wraps around the rear 1/4 window (see close up pic of AEX734 from a local AC owner). I approximated the changeover date based on a limited Google search of Aceca images using cars with verified chassis numbers. In this search, I discovered that at about chassis number AEX674 they did away with the old style rain gutter arrangement in favor of a single gutter. I assume they developed a better method of securing the roof without the wood. Possibly allowing them to weld the seam or wrap the roof skin around a tube of steel?? Perhaps others with later Aceca's know how this was done. I think the repair your rebuilder is suggesting sounds reasonable. It may not be entirely correct for your year Aceca, but going back to the original system seems difficult. You should also evaluate your existing rain gutter closely, since it doesn't appear to be OEM.

Side note:
The switch of rain gutter design by AC may have also been when they switched from the dropped (cloth) headliner on the early cars to the felt headliner that's glued directly to the aluminum roof panel on later Aceca's. This would make sense since they did away with the wood framing in the roof at that time.

There are a number of subtle differences in the construction of the earlier Aceca's vs. the later ones. Just one of the things that makes owning these hand built cars more interesting. :)

Best Regards,

John
AEX521

[Vincent998]

Thank you for your most useful and informative reply!! Since I posted my original help request, I had learned some of what you explained. Looking at photos of other cars, I could see that the rain gutter changed some time around 1959-1960, but could not find photos showing the details - which you have now provided.  The gutters now on my car are clearly not original and were hand made by some former owner to be similar to the second (post 1959) gutters that wrap around the rear quarter windows but (in my car) do not cover the slits. Therein lies the problem we need to solve. We will have to remove the existing gutters and make new ones. Discussing what would be a good solution with my rebuilder, we came to the conclusion that he could make the new rain gutters in a "J" cross section and then actually glue them (long side to the roof) over the slits using a permanent adhesive that is currently used in GM car production. That would both permanently cover the slits and prevent water ingress. Your photos also show that the gutter-roof joint is not invisible (picture 6 and others) and so does not have to be filled. Furthermore, we can revert to the original location behind the quarter windows, using the original holes (which are still present) as a guide to correct placement. Thanks again for your help. If I have other questions about the gutters I'll send you a PM.

[Aceca289]

I'm glad you found my post informative and that you plan to take the effort to revert back to the original design. It sounds like you're serious about restoring this old Aceca back to how she originally looked. Be careful removing the rain gutter...you may still have one piece of the original rain gutter on the "A" pillar as there was a joint in the rain gutter on the "A" pillar as seen in these pics.

I would be interested in the specs on the high tech glue you plan to use to put in my files for a proper fix of my paint issues when I eventually get to painting my car again.

Yes - send me a PM and I can take some detailed measurements of the end of the rain gutter so you can get it dimensionally correct.

Best of luck,

John

[10kph]

Hello, I am an Aceca man and have restored all variants over the past 40 years. The original gutter trim with rubber/plastic insert was used on caravans in the 50s. I remember obtaining a similar alloy section from a vintage car restorer supplier but the curved rubber was replaced with an alloy piece on the same extrusion that was bent over to cover the screws.. I would try to make good the wide gap with one pack bonding sealer such as sikaflex whick will key well to metal and wood but will flex to allow for heat expansion. the same product will also form a watertight seal for the moulding and can be overpainted. Flexible mastic was originally used. Check the finish shape of the gutter at the rear I think it was angled longer at the bottom and that they stopped in late 66
    Regards
      Tony