Has anyone (Russ?) photo documentation of filling firewall holes? I'm sure the bigger holes are only done with welding, but I'm not sure how you would fill all the little screw hole sized holes. I know a lot of you have done this, but does anyone have the photos that show what needed to be done and the order that you did it? Just wondering~ Thanks!
I went the other way. Instead of filling them, I covered them. I made a brushed aluminum firewall cover. I stripped everything off the firewall, and then installed the cover. Worked fantastic. Of course that's only one option......Mike
Plugging Holes I'm amazed no one else chimed in..... I use clear RTV and you'll be pleasantly surprised when you take the time to plug up ALL those pesky little holes as they draft in much noise and engine stink , more than you'll ever know until you cork 'em all up
My firewall is real dark so I used that tar-like gunk that auto A/C people use to seal ducts. It comes in sheets about a foot square with paper on both sides. Got it from FLAPS. It is easy to pull off in strips about 1/4" wide and form to whatever shape you need. Stays soft. Sorry, I don't know the name.
Its quite simple really. Just weld them up. I got rid of ALL unused holes on the firewall for my 52 just by using my mig welder. Yes the larger holes (anything bigger than a screw or bolt hole) I welded in a piece of filler metal. When welding up the screw and bolt holes I just made some quick tach welds around the outside of the hole to build up the thickness of the metal around the edge and just kept doing that until the hole was closed up. Did it on both sides and then followed with the grinder on the engine side. I didn't bother grinding down the welds on the inside because they wouldn't ever be seen anyways. I have some pictures of before and after if you want. Will post them later.
Get some copper pipe nipples and hammer them flat. Clamp them behind the holes to support the welds. Weld material will not stick to the copper. Big holes, weld washers or cut filler pieces out of sheetmetal, then mig them in. We filled a few holes in the 53 this way. Take your time, don't build up too much heat. You could cut out a whole smooth piece from aluminum or stainless, grind in some swirls, then bolt over the existing firewall . I bought a whole assortment of hole plugs from lowes and filled the holes in my truck. Use some of the blck strip caulk from NAPA to seal up from behind them, makes a hell of a difference in noise and odor, they can be painted or left chrome. DS sheetmetal makes a really nice smooth firewall kit, I installed one in the 50.
Now that I would not try, just too risky, especially holes that big. If you can't or do not want to weld you could glue the hole plugs on from the inside and then apply bondo on the outside. This way the bondo would have a strong backing and would only have to be as thick as the firewall sheetmetal. I did a similar thing in 1 spot on my firewall where I couldn't weld my filler piece flush so I cut the piece a bit bigger than the hole and then welded in from the inside and tach welded it in a few places from the outside, then applied the bondo.
That is what I did. I welded sheetmetal on the back side of all holes big and small then welded the big ones and bondo to the small.
I will mention McMaster-Carr as a source for odd hardware again. Look at the snap-in hole plugs. If you can find the right sizes, this would be a simple solution. http://www.mcmaster.com/#steel-hole-plugs/=29hykh Greg
Thanks, guys! Wow! No photos, but detailed enough descriptions that "I get the picture"! Obviously there are L-O-T-S of options. My firewall has 16 holes about the size of a pencil. (Pea sized) I also have two that are about the size of a dime. On the smaller ones, I thought about getting some small machine screws, nuts, and lock washers, and installing them with the slotted side out towards the engine. That would give the viewer a mental test as to what all those screws were holding in place~ Maaaaaaaaaaaaaybe that's his SECURITY SYSTEM!!! All I knew to do for the dime sized were to do the welding thing. (Which I am REALLY trying to avoid!) So thanks guys! I'm sure you gave a lot of others out there something to think about as well! MUCH appreciated! BTW, I look forward to the day when I find out why someone perforated my firewall like that. The cowl vent didn't give enough ventilation?
Don't be afraid to weld. It is really simple. I tought myself to weld on my truck with a very small 110v mig. I have since stepped up to a biger 110v mig and now I LOOK LIKE i KNOW WHAT i'M DOING. I bought the Lincoln from Lowe's....about $500. It has 4 heat settings and wire feed control. It has gas attatchments, but I haven't bothered with that yet. Just go slow and control the heat to prevent warping and burn through. Come by the house, I'll have you welding in about 30 min.
You can also use the small plastic hole plugs for the screw holes, then cover your firewall with stickers......adds to the competition look and makes it go faster.....
Zig, if GM had some extra time to spare right now, they could set your mind at ease. They're a little busy right now, so I'll answer on their behalf. (GM letterhead) Mr. Ziggy Stardust Pittsburg, Kansas Dear Mr. Stardust: Re: your entry "BTW, I look forward to the day when I find out why someone perforated my firewall like that. The cowl vent didn't give enough ventilation?" We have reviewed pictures of your firewall and find that it is, in fact, the way we intended it to be. Given the various RPO's, special options, and accessories available to you, our valued customer, ALL cabs are pre-drilled to accomodate a wide range of combinations. One example is our heaters. Our recirculating heater is configured differently from our fresh air heater. Our firewalls are predrilled for either. If you choose the recirculating heater, we supply a large "blank" to screw over the hole necessary to mount the fresh air unit. Rest assured, Mr. Stardust, that we here at GM are proud of the money you have spent with us in the past and sincerely hope that you continue to do so. Sincerely, Your friends at Generous Motors PS: The cowl vents only work when opened.
some general pictures of the work I did to my firewall. http://s175.photobucket.com/albums/w124/rockfan1815/firewall 2/
Dime sized Holes with no welding Get an old appliance dishwasher or refrigator door & rob steel patches. Rough up the inside of firewall and 1 side of patch. Take duck tape and put on smoth side then use bundo and smear it on patch. Plaster the patch over hole and let tape hold it until dry. Apply bundo to firewall and smooth to your liking. Any leftover sheet metal can be screwed to the side of your work shop for future use.
Thanks! I suppose you could use that adhesive that Evan said was as good as welding to hold the patches in place as well? Great idea!
That's smooooooth! Thanks, Chris! At the time I painted my firewall, I was more concerned about how the paint scheme would turn out. Now that I know that, I'm thinking I'll go back in and fill all those "factory" holes.
