Centre of gravity for rotisserie

[GavinL]

in the not too distant future i am stripping my car, and mounting it on a rotisserie, so that i can replace spring hangers, sills, etc. My question is, where is the centre of gravity on a saloon? ive found this on You tube https://youtu.be/IGLWtwZOYsI which implies for a convertible shell it is about 300mm below the mounting through the battery box. With a roof, i assume the saloon is lower than this, possibly in line with the front bumper mounts? i'd also be interested to know how much this is altered if the front suspension is left in situ. i realise that i wont get this exact, and it still has to be high enough to allow the car to 'roll over' completely, but anything i can do to make turning the shell easier would be appreciated.

[RobThomas]

Yes, the Tourer CofG is below the battery box hole. I resolved the problem by being able to lock the rotating rod in position. The CofG changes every time you add or subtract weight such as adding doors and springs for alignment etc. You'll never be able to work it out exactly and will only make the job harder. I could rotate the bare Tourer shell with a 2 foot bar with no difficulty. If you use a scaffold tube it may well bend. They aren't really meant to take any side loads, just in-line. That battery hole is ncely towards the geometric centre of the car so less chance of blocking yourself in against the wall if it slips!

Might be best to drill 4 holes through the ends so you can slip a bolt through the hole to lock it in place?

[GavinL]

Thanks Rob. Out of interest what diameter / wall thickness of tube did you use? Did you build your own rotisserie ? I'm proposing building two hinged A frames out of 50x50 3mm box, with an M10 tie bar so that I can adjust the height.

[RobThomas]

If it were me doing it again then I'd be making a massive 'spine' out of 4 pieces of 50x50 box to make it stupidly rigid so I could run brackets off of it to hold the floor, A and B posts in place. The round ends can be anything but probably best to have the sleeve loose so it can't easily jam. A 12 foot scaffold pole is almost worthless for rotating a shell unless you don't need to jig anything up during the rebuild.
My Sprite rebuild used 3 scaffold tubes welded together and it wasn't quite rigid enough with the pole running close to the front steering rack mounts and the rear bumper area.
The last Minor rebuild used a portable/mobile frame on wheels. Mostly 40x40x3

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[oliver90owner]

My rolling shell was turned on its side for welding, using a cradle that basically fitted to the wheel studs. The kit now resides in the roof of my garage. Won't turn it completely upside down and not totally appropriate for a bare shell, but was a useful tool.

RAB

[Fingolfin]

I rolled my Mog's bare shell onto its side, supported by several large tires! Perfectly stable and easy to get around, and no harm done to the shell - though it was in fairly strong condition to begin with.