Author Topic: Welding a NLA gas tank  (Read 284 times)

Offline bikewiz

Welding a NLA gas tank
« on: May 07, 2018, 09:34:22 PM »
OK first and foremost, I didn't blow up the tank or myself. My MK5 SPI type tank is NLA. The best I could replace it with is a 1275 GT tank without the vent or an MPI tank with more big holes (for the fuel pump) than the rust in mine. So being the resourceful idiot I figured I'd weld the rust holes....
First step (obviously) drain out the gas.
Second step rinse the tank with a detergent bicycle degreaser  (Pedros Degreaser)
Third step rinse with the hose for "like forever dude"
Fourth, Dry the tank with a combination of compressed air and a heat gun.
Fifth, Do a sniff test. Question: does it smell like gas? No, so maybe just maybe it won't blow up.....
Six, sniff again after you went outside and took like 5 or 600 deep breaths, just to make sure.
Seven, just to be on the safe side purge the tank with Argon.
Eight, sniff again....I'm completely baffled at this point if gasoline was actually invented yet....
Nine, Figure "what's the worst that could happen"?
Ten, Run compressed air at 10 psi flow thru the tank... It's a big step baby, attach the ground.
Eleven, Close your eyes and strike an arc.....
Twelve, really? It didn't blow up?
Thirteen, realize those dudes on the internet are stupic...
Fourteen, Damn, this shit is thin...
Fifteen, burn a few holes thru and fill them in...
Sixteen, damn bitch. It worked. Grind them back, prime and paint.
Seventeen, reinstall, fill with gas, and say "I can't believe it works"
Eighteen, drink what ever your poison is to make your hands stop shaking because you just dodged a bullet......
« Last Edit: May 08, 2018, 06:45:12 AM by bikewiz »

Online 94touring

Re: Welding a NLA gas tank
« Reply #1 on: May 07, 2018, 09:40:55 PM »
Lol.  Ok so this verifies it, my worst welding fear of blowing myself up if I decide to fix up the plethora of rusty tanks I have  is perfectly safe.
« Last Edit: May 07, 2018, 09:42:48 PM by 94touring »

Offline bikewiz

Re: Welding a NLA gas tank
« Reply #2 on: May 07, 2018, 09:42:39 PM »
Ya and I suck at welding....

Offline jedduh01

Re: Welding a NLA gas tank
« Reply #3 on: May 08, 2018, 10:27:33 AM »
And i avoided all that on a moke tank with  Tank Patch Epoxy!

Good to know it ' can' be done ..

Offline Jimini II

Re: Welding a NLA gas tank
« Reply #4 on: May 08, 2018, 11:22:25 AM »
I tried welding a Moke tank a while ago and it was so thin i was making things worse. A friend came by and tried brazing it with not much better results. In the end he soldered it with very little heat it was the perfect combination and held up fine apart from the rust that loosened up which clogged up the fuel filter, amazing as i washed it out several times and ran a strong magnet all over the inside of it before repairing. 

Offline Nicholasupton

Re: Welding a NLA gas tank
« Reply #5 on: May 08, 2018, 01:11:30 PM »
FYI MPI and SPI tanks are interchangeable just use the correct pump /sender for your application. Also the trick to welding gas tanks or any enclosed item it to back gas the tank to shield the back of the weld. Makes things go quite a bit easier.

Offline bikewiz

Re: Welding a NLA gas tank
« Reply #6 on: May 08, 2018, 01:45:02 PM »
FYI MPI and SPI tanks are interchangeable just use the correct pump /sender for your application. Also the trick to welding gas tanks or any enclosed item it to back gas the tank to shield the back of the weld. Makes things go quite a bit easier.
I was going to use Argon but the regulator I was using decided to quit just as I was getting ready to weld, I was only able to purge it before it quit. My car is no longer SPI it's converted to carb I was under the impression the MPI tank has a large hole in the top for the pump correct?

Offline MPlayle

Re: Welding a NLA gas tank
« Reply #7 on: May 08, 2018, 03:02:15 PM »
The SPI tank also has a large "port" in the top for the 'in tank' fuel pump.  The gauge sender inserts into the side.

I know from where I converted "Flur" from SPI to carb.  I was able to obtain a regular carb tank and swapped tanks.  Sold the SPI tank to someone else doing a VTEC conversion and needing a fuel injected style tank.

The standard (carb) tank has the gravity fed line out the bottom.  The FI tanks had the pump in from the top and both the output line and return line attached to the top of the pump assembly on the top of the tank.


Offline bikewiz

Re: Welding a NLA gas tank
« Reply #8 on: May 08, 2018, 05:51:15 PM »
The SPI tank also has a large "port" in the top for the 'in tank' fuel pump.  The gauge sender inserts into the side.

I know from where I converted "Flur" from SPI to carb.  I was able to obtain a regular carb tank and swapped tanks.  Sold the SPI tank to someone else doing a VTEC conversion and needing a fuel injected style tank.

The standard (carb) tank has the gravity fed line out the bottom.  The FI tanks had the pump in from the top and both the output line and return line attached to the top of the pump assembly on the top of the tank.
I'm not sure which tank this is then. It has a gravity feed out the bottom, a vent with a line from the top, restricted neck with a spring door, diagonal strap, and the fuel lines exit through the large oval hole in the trunk floor. It originally had a 3 hole rubber grommet I replaced it with a 2 hole grommet, one for the fuel line one for the vent. When I got the car it still had an extra unused hard line running from back to front, which I assumed was an injection return line, unless it was a vent line to a charcoal filter? My best guess is it's either a WFE10420 or WFE10093 This car has suspect lineage.

Offline Jimini II

Re: Welding a NLA gas tank
« Reply #9 on: May 09, 2018, 03:15:36 PM »
You may have a carbed Canadian fuel tank they had a different fuel cap system, definitely not an SPI or MPI tank.