Fuel tank fabrication project

[Aussie Mike]

Thanks Scotty, It'd be good to catch up again.

Here's a bit more detail on the mounts.

I machined up some steel threaded bosses. These slot into a hole I've drilled into the chassis rail and will be welded in place. They are just tacked at the moment while I set every thing up.



Here you can see the mushroom shaped bushing that goes through the rubber. There is a 10mm cap screw through the center that clamps the bush against the chassis rail. This can be done up tight and and the set length of the bushing stops the rubber from being crushed. I will probably lock wire them as well just in case.



Just got to tack weld the bracket to the tank now and then pull the whole thing out and weld it properly.

Cheers

[Mando]

Hi Mike, I think the side of the tank will crack at the top of the bracket once you fill the tank up with juice and bounce that weight around on the roads. I hope I'm wrong.

Regards.

[Aussie Mike]

Why do you say that Mando? Just curious about your reasoning. I've had some concerns about hanging the tank from brackets off the sides.

I've tried to spread the load over a large area. This backing for this bracket is approx 4" wide by 3.5" tall. The brackets for the front of the tank where most of the weight is will have a larger backing to spread the load over more of the sheet. The aluminum sheet it's made from is 2.5mm thick so should be pretty sturdy.

I looked at the way Brown Davis made their mounts to get some ideas.

Brown Davis Motorsport - Roll Cages, drop tanks, aluminium and custom fabrication, race vehicle preparation

The drop tank under the Torana is about 120L and I reckon mine will be about 80L.

Cheers

[stumpeater]

Hi Mike, when I built my stumpeater, the 3mm steel (80 litre) hydraulic oil tank I made had a similar bracket to yours mounted on the side, and that cracked along the top weld and had to be reinforced with a big plate. It does cop quite a lot of low frequency vibration, but also would have been damped by the oil. I notice the Brown Davis tank has the brackets going from top to bottom which would stop any flex in the walls. My two bobs worth. Not being picky just trying to help, it would be a pain to repair the tank after it has had fuel in it.

[Rob. Smith]

Your mounts are (hanging) on rubber grommets. That seems to me a good idea and I think that would be sufficient....BUT...on reading all the other comments. What about making supporting straps under the tank with a rubber sleeve. Like the torana set-up.
Attach the straps to your nice mount brackets. With an adjustable fitting ? to pull up the play. just my thoughts.

[Mando]

Hi Mike, Stumpeater hits the nail on the head with his comment that the plates welded to the tank "might" need to be much bigger to spread the load. I don't think the rubber mounts at the size they are at the moment will make any difference because by the time you tighten up the bolts enough to stop the tank from bouncing the rubbers might as well be a stack of metal washers. That's my 2 cents worth!

Regards.