Holden VC Commodore Roll Cage Installation - Our Shed

By: Dave Morley - Story & Photos

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holden commodore rollcage holden commodore rollcage

Morley now has a roll-cage for his hillclimb project car

 

Project Hillclimber: '80 Holden VC Commodore SL

So now I have a roll-cage for my hillclimb car. Actually, what I really have is an anagram of a roll-cage, because it’s still in about four major pieces, as it came from Brown Davis. The first thing I did was unpack it and then do a rough assembly beside the car. And as I’m looking at it, I’m wondering how the hell what looks like a kilometre of powder-coated steel tube is ever gonna fit in the VC Commodore.

| Project Hillclimber roll-cage prep

Holden -commodore -rollcage -6Installing that lot in the car is like building a ship in a bottle

The thing is, the cage was made on a jig, so unless the car is twisted or bent in some major way, it really will fit. It’s just a question of faith. And a fair bit of wriggling and jiggling to get the pieces inside the Commodore and then bolt them all together using Brown Davis’ patented joining system that allows a bolt-in cage to be more or less as safe as a weld-in job.

Holden -commodore -rollcage -2Should be enough to keep the roof off Morley's noggin

I’m not sure if this is the best way to tackle the job, but my method consisted of getting all the bits and pieces inside the car and loosely bolted to each other. From there, I could drill the holes in the floor to accept the mounting bolts and loosely bolt the cage down. A bit of lube made the Unbrako bolts for the patented joins go in a bit easier, and a second pair of hands made nipping up the under-floor nuts and spring-washers much, much easier. Thanks little bro.

You also need to include a metal plate of a particular minimum size under each nut and washer, too, so that the fasteners can’t simply tear through the floor should the big one occur. And those plates also have to have radiussed corners to make them less likely to tear the metal themselves. The nice part is that when you buy a cage brand-new from somebody like Brown Davis, all that hardware – in the correct grade and size – comes with it.

Holden -commodore -rollcage -4Triangular bracing makes for rigid structures

The only really tricky bit came when I went to bolt in the front (A-pillar) downtubes of the cage. The holes I drilled lined up fairly inconveniently with the edge of the factory front jacking-point, meaning the metal plate had nowhere flat to sit. So, I stuck a cutting disc in the die-grinder and cut myself a slot in the jacking-point, thick enough to let the plate slip under the jacking-point and snuggle up against the flat floor. Not sure if that’s how the pros do it, but that’s how I did it. And if the nice man from CAMS doesn’t like it, I can always weld up the slot to make the jacking-point, floor and metal plate all one piece and restore the original integrity.

Actually, I might do that anyway.

Holden -commodore -rollcage -3The patented bolted joint by Brown Davis does the trick

The other thing I specified when ordering the cage was a footwell-intrusion bar on each side. The Brown Davis design cleverly incorporates these into the side-intrusion bar, so instead of the side-intrusion bar attaching to the A-pillar leg, it continues into the footwell and bolts to the front inner-guard. Clever.

Holden -commodore -rollcage -5

In theory the bolted cage will be removable and reusable

Now that the cage is in, I can finally get around to mounting the seat, harness and the million or so other little bits and pieces that a race-car needs. For the seat, I plan to use the factory mounting points (because they’re reinforced and probably the strongest part of the whole car) but I’ll chuck away the original runners. I don’t need the seat to be adjustable, and I reckon the runners only increase the chances of the seat coming loose in a big shunt. Also, making my own seat mount means I can mount the chair nice and low to keep the C of G down as well as to allow clearance between the roll-cage and my big, boofhead.

 

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