Discussion Forum - Northstar Chevelle Club

seagrams72 · Active Member

Welding in a Tank Sump

Tim H · Mega Poster

We welded one in my son's race car last year but we cut the tank in half removing the top. It's always a bit scary welding gas tanks but as long as it is flushed and air dried well it works good.

Back in the early 70's we used to solder alot of tanks that had pin holes because of the good old Minnesota winters. We used a larger soldering iron and would unplug it once it was hot.

Not sure where you are located but some body shops will do it just call the local small shops and ask, if nothing else they might be able to point you to someone locally who would do it.

Chris R · 2K+ Club

I think Tony had someone do this on his stock tank.

Pushrod · Active Member

you can try Johns Custom Welding in bloomington mn he might do it.

Tony Hoffer · Moderator

Youll have to go well beyond welding.. the high nickel content of the metal makes for some real caterpillar welds.. then you have to seal the tank from the inside..

Those aftermarket sumps leave something to be desired...the fuel sloshes up out of the sump during hard braking with under a half tank of gas. I have my old one all done if you want to buy it....

-- Edited by Tony Hoffer on Thursday 12th of January 2012 09:18:22 PM

seagrams72 · Active Member

Thanks for the input. I have heard mostly good news in the past about them so I decided to try it. I cannot afford the high $$ aftermarket sump tanks and there is no way the trunk is getting sawzalled for a fuel cell so I figured this may be a good option.

Tony, sent you a PM on the tank.

I have heard of people not drilling the recommended size holes in the tank (about 5, 2 1/2" holes)and instead driling multiple smaller holes. Doing this to create more of a baffling affect. This may help the starvation problem under braking.

Bungy L-76 · Active Member

I read in some hot rod mag where they made three cuts to the tank. Two on each side and one in the back, then pushed the metal up into the tank thus creating a baffle to stop fuel starvation under braking.

Lost in the 60s · President

Andy, I sent you a PM.

Dave Seitz · Mega Poster

I was told the trick they use on big equipment tanks. Connect a shop vac of some other type of positive air blower to the tank. DO NOT draw fumes through the the air source in a vacuum configuration. When the air suppy has helped dry the tank and fumes have diminished it is safe to weld. THE AIR SOURCE MUST STAY ON DURING THE WELDING. If the fumes are at a low level with the a positive air supply providing more air then fuel it will not go boom. That is the key to doing it.

67ss · 1K+ Club

I welded my tank on the camaro, it was no big deal. I drained the gas out let it air dry a day or two. Then hosed it out a couple times with water. Then with the sender out and fuel fill open throw a match in to flame it out for any residue. Then I had no problems welding on it.

-- Edited by 67ss on Saturday 14th of January 2012 08:15:20 AM

bowtie · Secretary

I had a guy named Don in Eagan weld mine. He did the sump and the return bung. I believe he did 3 large holes, but left the rest of the structure intact. That way it gives support and helps sloshing a little too.

Chris R · 2K+ Club

You might do some searching on the web and even search Team Chevelle or any of the other various performance forums you might like and see whats been done.

seagrams72 · Active Member

Thanks for all of the suggestions. It looks like I will be purchasing an already sumped tank though.

Bowtieman427 · Active Member

I will have to do something different with my tank one of these days. I get funny FP readings when is less then 1/2 full. Do not know anything about its setup. It is drawing from the top of the tank. My return is the original. When I go racing I go with a full tank. What Tony has pictured above looks nice.

-- Edited by Bowtieman427 on Sunday 15th of January 2012 07:01:27 PM

-- Edited by Bowtieman427 on Sunday 15th of January 2012 07:23:58 PM