Fitting Aftermarket petcock to fuel tank without blowing up

A few weeks ago, I was having ignition trouble. Diagnosed it as the pickup coil and finally, after ordering a part and swapping out the WRONG COIL, I finally got it together and have spark in all 4 cylinders. Success!

However, I also have a leaky petcock. After reading about the rebuild, and the issues some people have after rebuilding, I opted for an aftermarket simple On/Off/Res model. Working on installing it, but there's a problem. The valve protrudes into the tank slightly, and the hole in the tank is just a little too small to let it through so that the petcock sits flush. I didn't even notice until I tried installing the first time and realizing fuel was leaking from where it just didn't quite seal.

If volatile chemicals weren't involved, it would be really simple to just enlarge the hole in the tank with a drill, but I'm scared of throwing a spark and blowing myself up.

From what I can tell, there's no reliable way to completely drain the tank, right?

I could flush the tank with a garden hose, which would probably keep me from getting blown up, but then I'd have to find a way to get the water out.

Any ideas?

Maybe I can grind a little metal off the petcock's protrusion so it fits the fuel tank's hole?

Or use some kind of sealer to make a really big gasket?

Any ideas welcome.

 

Sure there is, or we'd never be able to ship a tank and that happens all the time.

Start by draining out as much as you can, then remove the petcock altogether and let it all drain out. Slosh any remnants around, repeat. Put your shop-vac on "blow" and stick it on the inlet and blow the remaining gas out.

Then either flush with soapy water followed by WD40 and more shop-vac; OR--

Hook up your shop-vac hose to the tailpipe of your car, and fill the still gasoline-ey tank with Carbon Monoxide. It won't support combustion.

 

Thanks. That sounds much more reasonable than some of the other ideas I came up with.

Gonna try it tomorrow.

 

I generally use "plan "A" if I'm going to ship a tank.

"Plan "B" is more for quick repairs.

 

Plan "b" sounds kind of fun though. You just need to make sure your car's the hose isn't leaky.