Firewall crack repair

[kmoses]

While checking my spider for stress cracks at the firewall where the clutch cable enters the drivers compartment I found this;


After digging into this attempted repair I found the firewall had been repaired with brazing rod and riveted steel plates.
I ended up cutting out everything that was questionable and ended up with this.


I was not wild about welding so close to fuel lines so I machined steel plates that bolt on each side of the firewall.


After machining the clutch mount hole it will be sprayed with epoxy primer, installed with seam sealer and painted along with the engine bay. The socket head screws will be changed to button head screws for a cleaner look.

[AriK]

Nice solution, thanks for posting. We all should be keeping a closer eye for fatigue cracks anywhere on our middle aged cars. It may be surprising what we discover.

[seabeelt]

Nicely done sloution without having to weld

[v6spider]

For my spider I designed a strengthening plate in CAD and had it cut out in 1/8" aircraft grade stainless steel. It mounts behind the firewall and is held in place by the brake booster bolts. I riveted the plate where the cable comes through to my backing plate.
If you are interested I can get the CAD file and send it to whoever needs it.

[kmoses]

That is a nice clean repair you did, thanks for the offer but your firewall doesn't look quite like my '79. What year is you Spider? I do have a question about the clutch cable plate that you attached with rivets, were they riveted on from the factory or did you cut one from a donor car? The reason I ask is that I have never seen a firewall that has not been repaired.

[v6spider]

That is a nice clean repair you did, thanks for the offer but your firewall doesn't look quite like my '79. What year is you Spider? I do have a question about the clutch cable plate that you attached with rivets, were they riveted on from the factory or did you cut one from a donor car? The reason I ask is that I have never seen a firewall that has not been repaired.

Mine is a 72.. The plate was spot welded from the factory. What I did was preventive because my previous spider v6 conversion car , which was a 74 cracked where yours did. The backing plate will work on any spider. The earlier spiders like mine had a Reenforcing plate on the fire wall. I added the rivets to connect that part to my backing plate.. My clutch is a 10" diameter clutch intended for a chevy v8 camaro with a 4 speed. The pressure is probably twice that of the stock spider clutch so the modification is absolutely a necessity. My engine is a carbureted Chevy vortec 4.3L v6 with over 300hp . my trans is a Borg warner t5 .. The posi rear end is out of a Mazda Rx7 gsl .

Cheers!
Rob

[kmoses]

Wow! that's some serious power to weight ratio you have there Rob. I'd say you now have more of a GTA (Ground Type Aircraft) than a Spider.

[v6spider]

Wow! that's some serious power to weight ratio you have there Rob. I'd say you now have more of a GTA (Ground Type Aircraft) than a Spider.

And fun as hell!


More pics at http://www.v6spider.com

Cheers!
Rob

[kmoses]

That's nice. It reminds me of when I was young and was told/asked by a engine builder
"speed cost money son, how fast can you afford to go". Then as now I responded "I can afford to go fast, just not that fast".

[Madmic]

Hello,

i'#m new to this Forum and I have a cracked Firewall.
Sadly I can't reach v6spider. does anybody still have the drawings and can send them to me?
That would be great.

[v6spider]

Hi fellas,

Sorry about the delay checking in here... I have been looking for the cad file i had upgraded my computer and transferred the files. At any rate, i am having issue locating the cad file.. still looking though i may have to contact my buddy at the waterjet shop and see if they have a copy of it..

Appreciate your patience..

Thanks!
Rob