Firewall Smoothing

Nov, 2012

 To go along with the smoothing of the engine bay sidewalls I needed to do something with the firewall to smooth it out as well. The main areas of concern are the openings where the heater hoses and AC lines go into the dash area, the factory access holes that were never used and just had plugs in them, the factory access holes that had wires or vacuum lines running through them, the cowl/firewall flange, screw & bolt holes, and small dimples scattered randomly along the whole thing.  All of this ugliness must be dealt with. 

I could have just made a new one piece section for the entire firewall, similar to the side panels but decided against this as I felt it would be more trouble than it was worth in this area.  Just a general smoothing would suffice here I believe.  I welded in small patch pieces behind the unused factory access holes that will no longer be used.  The smaller bolt and screw holes will be welded closed, there were also several small dimples that I have filled with two part epoxy.  The area where the steering column and brakes come through will be left alone except for the smaller holes and dimples.  The cowl/firewall flange area has been removed and re-welded to clean up that line.  The only area where I used new sheet metal is over the AC line and heater hose access panel.  I followed the outline of this shape and blended my welds into the firewall around the radius, just like on the engine bay side panels where the welds blended in with the hood hinge recess area. 

Since so many holes have been closed up we will be drilling and cutting through where needed for access points.  I will be combining wire harnesses to simplify bringing wire through those holes, and the same with any vacuum lines as well.  An aftermarket AC system will be going in under the dash so the original holes won’t be needed anymore, and anything that needs to be fastened outside will be adapted.  This will give us a much cleaner, neater look than the original factory firewall.

The firewall smoothing is not complete yet but very close.  It still needs some work, but other areas of the car have pulled us away for now.

 Firewall after removing most of the hardware and before starting the smoothing process.

 Filling some of the holes that will not be used again.

 More smoothing, including cutting the cowl flange and re-welding the three layers back together.

 Cowl seam re-welded.

 A few more steps, cowl seam has been sealed on top of welds.

 Dad, mom, and Alexandria having a good laugh.  Mom, you are hot!!

 Unfinished, but with a coat of POR15 already.

 A little closer look.  This is right before we decided to cover the AC and heater core area.

 Some more of Trent's Rooftop AC unit sheet metal.  This is roughed out and will be cut to fit with some trial and error fittings.

 

 Some of the holes are patched here, and the new sheet metal is welded in and ground smooth.

 With some body filler added.   My smoothing skills are very limited.

 Areas have been sanded somewhat.

 Areas have been sanded somewhat.

  Much more work will be needed on the firewall to really complete it the way I want it, but for now it is roughed in and we have been working on other areas of the car.

Comparison of the original cowl seam and after it was trimmed, welded and filled.