Gearbox crossmembers

[Glenn 'Stinky' Stankevicius]

I am after a simple gearbox crossmember solution without the expense of a chassis kit.
The current Red/Aussie 4 speed has a custom crossmember that has bolts going through (horizontally) to mount it to the existing floor bracing. I'm not an engineer by any stretch but I think this is a really bad idea at best, disastrous at worst.
Seeing as the hard work has been done making the crossmember I was thinking of drilling holes for the bolts to go through the floor (vertically) and have a reinforcing plate on the inside of the car floor. Is this a sound idea or should I be looking at some chassis rails 

[FCRB26]

I had that with my first VL conversion i split the firewall and tore the plates out of the floor???




So maybe try to incoporate something of the old crossmembers?

[Hobbo]

Flat plate 200mm across the inside floor would be much better, Holden used same idea  for their factory towbars on early commodores

[Ed]

Stinky,

On an EH, I made a crossmember which had a C-section around the original floor bracing and bolted through the original bolt holes.  You could add some more bolt holes spaced further apart and add crush tubes etc... this is largely reliant on the integrity of the floor cross member though.

The cross member was hung from the rear of this and gussetted to the c section for strength.

C-sections were as large as I could make and followed the contour of the floor bracing.

Horizontal or vertical mounts will work provided you spread the load accordingly.

I've done both.. the vertical mounts were used in an EK wagon I had which dropped it's gearbox in Macksville en route to Byron Bay.. the floor member had rusted out so bad the box fell out as my mate was driving it. 

While sleeping in the wagon waiting for the next morning we also got robbed by the local indigenous folk... before a couple of drunk cops pulled up to question us.

Next morning the local panel guy opened shop for $150 and using some coach bolts  through the floor and plates above the floor bodgied it up... it worked for 12 months before the car was taken off the road.

Fond memories of an extremely ill prepared road trip!!


Cheers

Ed

[FCRB26]

Love the bodgey repair lasted 12 months

 a bit like a mates boat trailer snapped at mallacoota boat ramp so we straightened it and text screwd timber into the channel 3 years later it was still like it.



Pete

[NosFEratu]

Glen

We had the same problem with the van.  The transmission mount for the T700 was about 200-250 behind the original crossmember.  I tried the "c" fix using the orignal crossmember but abandonned that very quickly.  My fix looks a lot like an EK auto setup.  I welded al 40x80x1.6 rectangular tubing into the floor.

This is in two sections.  The first butts up to the front crossmember the original gearblox used to bolt to.  A second section is welded so it rises under the seat.  Once I had these done I was able to build the gearbox crossmember and bolted it to tabs on the new rails.  I did this without turning the car upside down.  I cut slots in the floor, pushed the tubing through by 10mm and welded from the top.  It works a treat and by the time we put in dynamat, underfelt and carpet no one could tell.  Maybe your upholstery guy could help.

The chevy V6 and T700 are pretty heavy and there has been no issues.  We have been to Orange, Melbourne, Riverland x 2 and Melbourne and back.  I pulled the car to pieces and checked all the fabrication, welding and floor integrity and there are no signs of any stress.

Kathi has put some shots on Nosferatu if you want to see how we did it.  It requires a MIG and about 2.0m  of Hills salvage tubing at cost of $10.  It took me a few hours to design it (after which I found I had just replicated an EK auto) the first side took about 4 hours to build and the second side about and 1 hour.

regards

The Butler   

[GOA350]

I was going to suggest looking at an EK auto floor but "The Butler" just explained it. That is basically how an EK is done except the EK one is spot welded to the floor.