firewall replace welding question

:HMMM: Ok guys I am installing a new bitchen firewall in a 34 fordor have a question regarding instructions on welding. In instructions it says carefully grind the edge of the cowl smooth, Are the talking about taking the lip that that comes over the firewall part of cowl grinding it down to be smooth with firewall. orignal way henry did it was the lip covered firewall and was only welded in a few spots in corners. ok next thing in instructions says take your time weld the edge of cowl as indicated looks like in picture they are welding right on the edge that was removed. I can't understand why you would remove this lip unless just to make a smoother aperance I like the way henry
did it. What did you guys do just weld spot welds we removed to get old firewall out and that's it or weld under lip also. And if so just here and there
or all the way around. Just a little confused don't want to mess up. I am including picture of new firewall just sitting in car not pushed in yet took a while to get old one out.

I have never done it, bit it looks like its made to line up at the flange, then just fill in the spot welds you drilled out. Then you could edge weld the two for a nicer edge.

Thank you just wanted some more input will just spot weld holes I drilled then see if I want to clean it up more by welding flange have a great day mark

I would do alot of measurements and only tack it in ,then do a mock up on the front sheet metal ,taking tons of measurements to keep everything straight.
After I was positivly sure it was correct ,then I would dissassemble and fully weld it.
That piece is going to set alot of reveals and alignment points in stone ,once you weld it fully.
Alot of measuring and looking can save tons of frustration and time later.......:3dSMILE:

DO NOT grind that rolled edge off!!

I think they're talking about smoothing the flange surface of the inner portion of the opening, as in taking off the burrs from drilling out the factory spot welds. You may need to go around with a hammer and dolly and straighten up some of the cowl edge so that you meet the flange of the new wall as evenly as possible. Once you've got the new piece in it's place (helpful to use several vice grip clamps) all you should need to is plug (or rosette) weld at each of the spot weld holes. That was what held in the original piece, should be plenty for the replacement. Unless the rest of the body is unstable for some reason, or if you've moved it around since cutting out the old firewall, it should be pretty much in the right shape. It wouldn't be bad to do a cross measurement of the opening before beginning welding to make sure it's square though. Also, if the flange on the new wall doesn't want to sit quite flat against the old cowl flanges in a spot or two (like the corners) a small tack weld to hold it down won't hurt. You can dress the weld later, and then do a nice, neat seam seal job and it will look better than new.

Here's what it should look like when you're done (before the seam sealing).

Hmmmm. Guess it's too late to say the front of the body should be cross braced and secured to a fixture of some type before cutting out the old firewall.....

Measure everything at least twice, and tack from the center out.... Works good to have another pair of hands around and hammer weld the spot welds as you go.. If everything is not square with the cowl and firewall, getting the rest of the front end together is going to be a nightmare!!!!

I just replaced the firewall in my 37 Ford with one from Direct Sheetmetal and they said to grind off the flange and weld the edge after the spot welds have been rewelded. http://directsheetmetal.com/pages/typeinstall.html

they provided self tapping sheetmetal screws to screw into every other spot welding hole to hold the firewall in place while you're doing the new spot welds. As long as the body was bolted to the frame during the firewall removal, I doubt that it shifted and the new firewall should pull everything back in place.

I'm assuming that the installation procedure wouldn't be much different between a 34 & 37 but I could be wrong.

Randy

Thanks guys for response body was shimmed and bolted before old firewall
was removed. Body is in real good shape every thing looks good on sides of
cowl good straight metal took care taking old one out this one is going to fit tight have mocked up front endd before taking old one out yes it is a night mare puting font end together but came out real straight and body lines looked good was planning on hammer dollying the flange first will take my time first time trying to do somthing like this also will pre fit and measure
before tacking then tack and measure again have to get a bottle of gas for mig welder. so have time to do dolly work and check every thing thanks for picture bob hope this one turns out that nice. think it will thanks again every one

Just a little update on firewall needs a little more welding and alot more grinding but looks pretty good finaly found room for brake power booster and reservoir. also made bracket under dash to help support sterring column.
Reworked brake pedal to clear column. these things were driving me nut's.
next have to put in new floor board in front and tunnel. Some of welds not real pretty but will grind out.:D

Looks like you did just fine. Congrats.

Thanks Bob took a little while but I am real happy with it

Looks great Mark!!!! Another one of those projects that is both very time consuming and very rewarding when done correctly!!!! Great work so far, keep it up!!!!!

thanks dave will try to post steering column brace really turned out nice