Topic: Roll cage on a BOF car with questionable body

I have rusty floors. That's an understatement. Frame is good, though.

Trans tunnel is OK, driver side floor is repairable, passenger side is a total mess.

Normally I'd weld a plate to the frame through a large cutout in the floorpan, and then build a box back up to the body. However, on the passenger side there's not much to weld to.

Do I...

- give up and lay down a 2x5ft sheet metal "patch" and stitch it to the tranny tunnel on one side, the frame on the other, and cut the oem floor off
- weld the cage to the frame and just throw some POR15-soaked e-glass over the passenger side to cover the holes
- some other option

My problem is further complicated by the fact that my firewall and rear deck need to be covered in metal because they're fiberglass and I have a non-fia fuel cell and an engine on either end of the car. In your experience, what's the best way to address that? Aluminum flashing and pop rivets? Or would a large sheet of thin-gauge steel work better?

K Car Stalker

Re: Roll cage on a BOF car with questionable body

On our LTD (big ass B-O-F car) the cage is welded directly to the frame. 

There's been some discussion about this before.  If you weld the cage to the body on a B-O-F car, you don't really get much protection. 

Weld it to the frame.  And then tie it into the floor, as much as you can.

2008- 2010:  1966 Volvo 122, "Charlie"
2010-present:  1975 Ford LTD Landau...doesn't have a name?

Re: Roll cage on a BOF car with questionable body

On then s10 based boat and Hombre, the frame was quite narrow so we welded some big outrigger boxes out of 1/8" plate to the sides of the frame and terminated the cage on those.  Very solid, never a question about them at tech. The forward bars didn't have room to do the same, but we were able to land the bars right over the factory body mount, so that's about as sturdy a place as any.

Three Pedal Mafia: IOE > Overall
Wartburg | Wagovan | The Boat | Rolls Royce | Civic Giraffe | Citroen SM | TR7 3800SC | Cressida | Isuzu Hombre
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4 (edited by firegremlin 2017-04-13 08:51 AM)

Re: Roll cage on a BOF car with questionable body

I'm welding to the frame regardless, my dilemma is just how sturdily should I attach/patch the body. The body is essentially two metal "roll" hoops that form A and B pillars and T-top frame, a formed metal floorpan (that's all but gone on one side), and two steel strips attached to the two hoops that run along the underside of rocker panels and act as body mounting points. The rest is fiberglass.

K Car Stalker

5 (edited by Spank 2017-04-13 09:25 AM)

Re: Roll cage on a BOF car with questionable body

The moke is essentially a body-on-frame at this point. I used as much of the original floor as possible to make a floor, and then filled in the gaps with pieces of Kenmore dryer and Frigidaire side-by-side. I welded the floor around the spreader plates so from above it looks like a traditional spreader plate and floorpan, but from beneath you can see the spreader plate is essentially completely on a section of box frame.

I'm not sure if this is what you're getting at, though.

But in the event of a fire, you really do want there to be no holes in the floor and all metal if possible. When I brought the CovVegge, Jay was super nervous about the fiberglass catching fire.

Interewebs says POR15 is flammable when dry and caustic smoke

I heavily recommend a filtered respirator when welding around POR-15. It contains isocyanates, which can cause massive respiratory problems.

I had some spare POR-15, so I painted it onto a burn barrel that I used to burn up old wood scaps and cardboard (50 gallon drum). Next time I used the barrel, the POR-15 caught on fire and then stopped and smoked like crazy. I can only assume the smoke is hugely toxic.

Re: Roll cage on a BOF car with questionable body

On the Plymouth the frame was super narrow so outriggers it was.  all went well until they looks at how our (amazing) chief mechanic and welder tried to tie the sheetmetal back to the spreader plates on the rear outriggers.  There really was not much more he could do tacking light gauge sheet metal to 1/8" plate welded to the heavy gauge frame.  There was daylight and lots of burned spots but they let it through.  we were probably talking 22 gauge on 1/2" steel (1/8" plate + 3/8" c-channel)..

Would a sealer or foil tape or something be more acceptable?  Plug welds would still show daylight between.