4.5 Hours -

Today was one of my longest build sessions in quite some time, so there are a lot of pictures.  Unfortunately, the day started off with a casualty.  I went through my normal routine…went into the garage, sat my camera on the workbench, and then proceeded to pick a podcast to listen to on my iPod.  As I was picking looking at my iPod, I caught some movement out of the corner of my eye.  My camera was slowly starting to slide off the bench because I didn’t account for the weight of the lens when I sat it down.  By the time I reacted, my camera was microseconds from jumping to its death!  I reached out with one hand, but the camera bounced out.  In order to save the $500 camera, I had to sacrifice the $200 iPod.  I dropped the iPod and caught the camera, after some more bobbling, with both hands.  As I caught the camera, I heard the iPod hit the concrete.  The iPod had taken falls with no damage before, so I had hope.  Unfortunately, upon inspection, I found multiple cracks radiating up the screen from one corner.  Surprisingly, the damage was only cosmetic, as all functionality seems to be intact.  Not a good way to start the day.

I had to sacrifice my iPod in order to save my camera. iPod vs. concrete...concrete wins.

With the camera safely situated on the workbench, and the iPod safely back in my pocket, it was time to get to work.  The first thing I did was finish the F-601J brackets.  I had already finished the right one, but the left still needed all the edges finished.   The vixen file makes quick work of rough edges even on thick aluminum pieces like these.

The F-601J brackets are finished.

Next, more fabrication.  The F-601E stiffener has to be cut from some .063 x 3/4 x 3/4 angle stock.  This is the only firewall stiffener that isn’t pre-cut and punched at the factory.  I guess that is because this piece goes below the  firewall recess and the firewall recess used to be optional.  On my firewall, the opening for the recess was already punched out.  Oh well, nothing hard about cutting a piece of angle to length and match-drilling it.

The F-601E stiffener had to be fabricated from a piece of .063 x 3/4 x 3/4 angle. Not sure why this is the only firewall stiffener that isn't made at the factory.

After the stiffener was finished, I had to make two F-601P spacers from .063 alclad sheet.  Again, these were pretty easy pieces to make, especially since I found some pre-cut alclad that was the exact size I needed.

The F-601P spacers had to be made from .063 alclad sheet.

Once the spacers and stiffener were made, I clecoed and clamped everything to the firewall, except the F-601J brackets, and started drilling.  Since stainless steel is tough on drill bits, I used a lot of Boelube throughout the firewall.  As I drilled, I also moved clecoes from one side of the firewall to the other so that I could keep track of what was drilled and what wasn’t.  A cleco on the forward side of the firewall meant that hole was drilled.  You don’t need a cleco in every hole to hold things together, but it makes for a good tracking system.

Once everything was made and clecoed to the firewall, I started drilling.

After all the stiffeners, spacers, gussets and weldments were final-drilled, I clecoed the firewall recess into position and final-drilled it to the firewall as well.

Finally, it was time for the hard part, the F-601J brackets were a bit tricky to line up and drill.  The have to be positioned on the back side of the firewall, clamped into place, and then drilled from the forward side of the firewall.  The brackets are flush against a stiffener angle on the vertical side, and spaced 3/32″ from a stiffener angle on the bottom, horizontal side.  To space the bracket accurately, I used a 3/32″ drill bit and then clamped the bracket in place.

The F-601J brackets had to be 3/32" from the bottom firewall stiffener. I used a drill bit as a spacer before clamping them in place.

The F-601J brackets are clamped to the firewall and ready to be back-drilled.

Once the bracket was clamped, I had to flip the firewall over, look to see if the gussets were still lined up, and then start drilling (assuming no adjustments were needed).  For the most part, this went well.  The only issue is that the vertical row of rivet holes is right in the bend of the angle.  There’s no way to adjust this, and I’m betting it will make the rivets tricky to set.  I’m not sure why the holes aren’t a quarter, or even an eighth of an inch more outboard here, but I’m sure the factory has their reasons.

The F-601J brackets are a little awkward to drill. Plus, one row of rivets ends up being right in the curved area.

After the F-601J brackets were drilled, I still had two more parts that had to be fabricated from .063 alclad sheet.  The first was the F-601TD plate.  This plate is a doubler for some of the brake line fittings that attach to the firewall.  One small hole is drilled in the part, then it is clecoed to the firewall and aligned so that the rest of the holes can be match drilled using the firewall as a guide.  The larger holes in the center had to be cut to 7/16″ with a unibit.  Unibits are far from my preferred method of drilling.  In my hands, they just don’t seem to make nice holes.  Oh well, these turned out OK.

The F-601TD plate had to be fabricated from .063 alclad. This bracket will hold some of the fittings for the brake system.

The F-601TD plate drilled to the firewall. The larger holes were done with a unibit...I hate unibits!

The last part that had to be fabricated for the firewall was the F-601Z fuel pump doubler.  This part is only need if you are using a carbureted engine.  Since I’m not sure what I’ll have, I decided to go ahead and install it now.  If I end up with an injected engine, no big deal, I’ll just install two bolts to plug up the holes.

As with the other fabricated firewall parts, the F-601Z was also made from .063 alclad sheet.  The plans are very clear on the dimensions and hole spacings for this part.  All of the holes could be drilled on part first, then the part was aligned on the firewall and used as the guide for match-drilling the firewall.

The F-601Z fuel pump doubler was also fabricated from .063 alclad. The plans are very clear in regards to measurements on this one.

The F-601Z doubler drilled to the firewall. This will only be used if I have a carbed engine.

After the F-601Z was drilled, it was time to start taking everything apart for finishing prior to riveting.  I’m deburring the parts as I pull them off, but only after I make sure they are labeled.  I only made it through a couple of parts before deciding to call it a day.  Tomorrow, I’m going to have a lot of deburring and countersinking to do.