Mountain-Metalworks
04-02-2017, 08:00 PM
One of the main reasons for my 3" firewall forward mod(link here) (http://thefactoryfiveforum.com/showthread.php?23864-Just-another-forward-firewall) was to have a clean engine-side firewall while still having a heater. I also wanted a glovebox, so the firewall forward was a necessary modification. Once complete, I moved on to trying to get the FFR heater completely between the dash and firewall.
First up was making a brace to stiffen the firewall since the heater would be attached to both the firewall and the 2" square tube. I needed to cut holes for the heater core inlet/outlets as well as any future wiring. Pretty common mod, the only thing unique is feeding in the heater core inlet and outlet lines as opposed to just wiring.
http://thefactoryfiveforum.com/attachment.php?attachmentid=65882&d=1491180315
Next I removed the motor/squirrel cage from the actual heater core so I could build a brace between the two that would help mount the entire assembly. The motor is by far the heaviest component of the entire system.
http://thefactoryfiveforum.com/attachment.php?attachmentid=65883&d=1491180316
To get the heater to sit in the proper alignment while fitting under the windshield cowl, I needed to modify the box itself. I cut the bottom(in my configuration...) 2" outlet off and will seal it up later with either a plate or just thick aluminum tape. That end of the box now sits almost directly on the 2" square tube. The top end of the squirrel cage sits about 1" below the body cowl, which will be more than enough room to suck in air. Not sure how loud it will be though...
http://thefactoryfiveforum.com/attachment.php?attachmentid=65884&d=1491180317
Next I made a new plate for the other side of the heater box that will act as both an additional mounting point as well as be my new box outlets. A round one for the driver's footbox, another for the passenger footbox, and the oval one for the driver's side defroster. The passenger side defroster will use the stock oval hole on the bottom of the heater box which exits in the firewall trough.
http://thefactoryfiveforum.com/attachment.php?attachmentid=65885&d=1491180318
Here it's mounted both to the heater box and the 2" square tube. You can see the heater box plastic has also been cut for access to the outlets.
http://thefactoryfiveforum.com/attachment.php?attachmentid=65886&d=1491180320
View from above. The inlet/outlet tubes go through the firewall brace, the heater box is attached to the 2" tube in two places, the firewall in one place, and I may add a brace to the dash tube but I'm not sure it's necessary. It's extremely rigid in it's current place, but I have yet to power up the motor on high to see what happens.
http://thefactoryfiveforum.com/attachment.php?attachmentid=65887&d=1491180321
Last pic just shows a side view of how I aligned the heater box, firewall bracing, etc... The two firewall braces are spaced evenly and centered on the firewall for a symmetrical engine bay view. I think I'll use stainless socket heads bolts instead of rivets, just an aesthetic thing though, it won't be very removable.
http://thefactoryfiveforum.com/attachment.php?attachmentid=65888&d=1491180324
Overall I'm extremely pleased with how it turned out. It accomplished my goal of a clean firewall, while maintaining both a heater and the glovebox in the new-style dash. My firewall is 3" forward which was actually more than needed, but now I also have plenty of room for wiring, the heater tubes once installed, etc... The only thing I'm slightly concerned about is a fan or heater core failure. The way it's built and braced, I think it would mean removing the body to change out either item. Even with rivnuts and bolts instead of rivets, it would be nearly impossible to access this area with the body on. It's a compromise I was willing to make though....
-TJ
First up was making a brace to stiffen the firewall since the heater would be attached to both the firewall and the 2" square tube. I needed to cut holes for the heater core inlet/outlets as well as any future wiring. Pretty common mod, the only thing unique is feeding in the heater core inlet and outlet lines as opposed to just wiring.
http://thefactoryfiveforum.com/attachment.php?attachmentid=65882&d=1491180315
Next I removed the motor/squirrel cage from the actual heater core so I could build a brace between the two that would help mount the entire assembly. The motor is by far the heaviest component of the entire system.
http://thefactoryfiveforum.com/attachment.php?attachmentid=65883&d=1491180316
To get the heater to sit in the proper alignment while fitting under the windshield cowl, I needed to modify the box itself. I cut the bottom(in my configuration...) 2" outlet off and will seal it up later with either a plate or just thick aluminum tape. That end of the box now sits almost directly on the 2" square tube. The top end of the squirrel cage sits about 1" below the body cowl, which will be more than enough room to suck in air. Not sure how loud it will be though...
http://thefactoryfiveforum.com/attachment.php?attachmentid=65884&d=1491180317
Next I made a new plate for the other side of the heater box that will act as both an additional mounting point as well as be my new box outlets. A round one for the driver's footbox, another for the passenger footbox, and the oval one for the driver's side defroster. The passenger side defroster will use the stock oval hole on the bottom of the heater box which exits in the firewall trough.
http://thefactoryfiveforum.com/attachment.php?attachmentid=65885&d=1491180318
Here it's mounted both to the heater box and the 2" square tube. You can see the heater box plastic has also been cut for access to the outlets.
http://thefactoryfiveforum.com/attachment.php?attachmentid=65886&d=1491180320
View from above. The inlet/outlet tubes go through the firewall brace, the heater box is attached to the 2" tube in two places, the firewall in one place, and I may add a brace to the dash tube but I'm not sure it's necessary. It's extremely rigid in it's current place, but I have yet to power up the motor on high to see what happens.
http://thefactoryfiveforum.com/attachment.php?attachmentid=65887&d=1491180321
Last pic just shows a side view of how I aligned the heater box, firewall bracing, etc... The two firewall braces are spaced evenly and centered on the firewall for a symmetrical engine bay view. I think I'll use stainless socket heads bolts instead of rivets, just an aesthetic thing though, it won't be very removable.
http://thefactoryfiveforum.com/attachment.php?attachmentid=65888&d=1491180324
Overall I'm extremely pleased with how it turned out. It accomplished my goal of a clean firewall, while maintaining both a heater and the glovebox in the new-style dash. My firewall is 3" forward which was actually more than needed, but now I also have plenty of room for wiring, the heater tubes once installed, etc... The only thing I'm slightly concerned about is a fan or heater core failure. The way it's built and braced, I think it would mean removing the body to change out either item. Even with rivnuts and bolts instead of rivets, it would be nearly impossible to access this area with the body on. It's a compromise I was willing to make though....
-TJ