Flipping a Tank?

[GS guy]

Well - that was a bust! Had the afternoon today to do a little buggy work, and decided to see about splitting that tank. Got out the grinder with cut-off wheel, my safety gear and started cutting! This part went relatively smoothly - lots of neighbors out cutting their grass so no problems making a racket in the back yard. Got the top separated from bottom OK, and it looked like the two could be rotated 180 degrees to each other and re-assembled. Then I started looking closer at the connections on the tank - drain bung, vents and filler inlet. They appeared to be soldered to the main tank body, cool should be fairly painless to remove. Got out the propane torch and was surprised at the low temp the "solder" melted at. Parts were very easily removed. Then as I was trying to heat and clean away as much solder from around the holes as I could, I noticed it looked like a thin layer of low temperature melting zinc or similar seems to be covering the entire tank - inside and out! I may be screwed on this one - but at least I get the 2-part guarantee: I get to keep both parts!

It doesn't look like I'll be able to do any welding on this tank with that coating everywhere. Further investigation indicates the metal is called terne plated steel, a zinc/tin plating applied to the bare metal before forming into a tank (I guess it's pre-tinned!). Supposed to be good at future corrosion protection - but probably not so good for any tank mods.

I pondered maybe hard or silver soldering it back together? Not sure that's the way I want to go, as the joint is not longer a lap joint but a right angle connection.

Looks like I may be looking for another tank to start over on. Any suggestions on a good vendor/brand to go to? My first thought was Wolfsburg West, but they indicate their tanks are powder coated - another red flag for my intentions.
Bummer.
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70's vintage Deserter GS buggy - undergoing transformation to Super GS!

[joescoolcustoms]

Hammer on with what you have. I scuff the area I want to weld, and weld them. Clean them well, and seal them with Red Kote products, both inside and out. No problems.

Every VW tank I have cut apart was Terne Plated, (original VW)
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Bad News Racing 2018 NORRA 1000 3rd in Class
Best Day Ever Racing 2022 NORRA 1000 2nd in Class and first All Female team to complete the race

Everyone is gifted. Some just do not open the package.

Looks like it was painted with a live chicken,polished with a brick and buffed with a pine cone

[GS guy]

Thanks Joe! Man - I need your inspiration!
OK then, lets work with what we've got. I guess I can hit the weld areas with either a mild flap disc or scotch-brite wheel before welding - should clean off at least some of the stuff.

Jeff
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70's vintage Deserter GS buggy - undergoing transformation to Super GS!

[joescoolcustoms]

I use a scotch pad on a angle grinder. A flapper wheel removes too much metal, and makes it harder to weld.

Safety first. Have good ventilation, you are welding around Zinc, and keep any fumes away from your eyes too.
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Bad News Racing 2018 NORRA 1000 3rd in Class
Best Day Ever Racing 2022 NORRA 1000 2nd in Class and first All Female team to complete the race

Everyone is gifted. Some just do not open the package.

Looks like it was painted with a live chicken,polished with a brick and buffed with a pine cone

[Letterman7]

Bonfire with the tank pieces in the middle? Melt off the tin, problem solved. Weld and coat as necessary...

[GS guy]

Letterman - Bonfire? I wasn't quite that upset about it!
I hear you on the safety aspects Joe. Ordering up a 3M welding respirator and P100 filters before starting that work. With some cartridge swapping I'll also be able to use it for some primer work. My welding outfit is set up for using under the carport - so usually he biggest problem is too much ventilation. I will be cleaning back the coating from the intended weld areas before striking any arcs though using the scotch-brite angle grinder discs.

Time to start working up some internal baffle templates and order up some bungs.

Thanks for the ideas guys!
Jeff
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70's vintage Deserter GS buggy - undergoing transformation to Super GS!

[GS guy]

Man - it sure slots in there well with the top reversed!
An underside shot from the drivers front wheel well:

Steering clearance to the firewall hole:

And top installed the "right" way:

I like it!
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70's vintage Deserter GS buggy - undergoing transformation to Super GS!

[Letterman7]

Cool! Now I get why you were doing that.. neat idea. Beats a custom tank being fabricated. Well.. you know what I mean...

[motoRAT]

now start welding
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Be curious, dismantle it all, reassemble it, go for a ride!

[GS guy]

No welding yet Moto - lots of prep work first.

Determined the best locations for the outlet and inlet bungs - got some 3/8 NPT bungs from Bungking and turned/modified them with a neck to insert into 3/4" tank holes. A chassis punch made quick work making the new holes. I did an additional modification of the return bung to add a short curved tube section to re-direct the fuel towards the bottom of the tank. The return comes into the side of the tank - this provided a better route for connecting to the chassis return line at the forward firewall. Tricky working with AN style fittings - challenges ones creativity!

Then set about making templates for the anti-slosh baffles. That took a bit of doing to replicate the tank bottom profile. These will be transferred to 18ga steel and with some additional holes and drain reliefs in the bottom, will provide a containment area for the EFI fuel pick-up. These will be welded into place once everything is 100% fitted up.

One thing I didn't catch earlier was whether the OEM fuel sender would work with the reversed tank set-up. I thought he bolt pattern was symmetrical and it could be positioned in multiple directions - Wrong! Only fits one way. Fortunately it looks like it would work fine with the reversed bottom relative to top - looking through the fuel fill hole in the corner of the tank. However, with the baffles in there, I'd have to do some creative clearancing to clear the swing of the float arm. Instead, I'm leaning towards using the Speedhut capacitance sender, which is a simpler straight tube extending down from the mounting flange. That'll sit comfortably down within the inner outlet bowl area. I know a couple of folks have used the Speedhut gauges - and read on a Samba-Vanagon post about them picking up every movement of the sender float/arm - making the gauge read a bit erratically? Haven't heard about any buggies having that issue?

Today's results:

In case you ever wondered where that vent line in the upper tank section went to:

Jeff
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70's vintage Deserter GS buggy - undergoing transformation to Super GS!

[GS guy]

Quick question on the new tank outlet - should I incorporate a short stand-off? I configured the drain fitting pretty much flush with the bottom of the tank. If I keep it this way am I asking for trouble with sediment, etc. getting in the line down the road? I've got a good size (2" dia. x 8" long) 100 micron filter before the fuel pump, and another much finer filter back by the engine. Now's the time to add a short stand-off to the fitting if I'm going to do it. Yea or nea?
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70's vintage Deserter GS buggy - undergoing transformation to Super GS!

[joescoolcustoms]

I like the idea of a short stand off just to keep the debris out of the line. Even though you have a filter, keeping scale and anything else in the tank I would think is a good idea. I put mine at 3/8 to 1/2 inch tall.
_________________
Bad News Racing 2018 NORRA 1000 3rd in Class
Best Day Ever Racing 2022 NORRA 1000 2nd in Class and first All Female team to complete the race

Everyone is gifted. Some just do not open the package.

Looks like it was painted with a live chicken,polished with a brick and buffed with a pine cone

[bim55]

Jeff, glad to see the your still making progress. Not sure if you're aware, but there are tube type senders for VW tanks that are different than the bent arm type. They drop straight down and I don't think they'd interfere with your walls?

Look at Cip1 and search fuel senders.

And VW did make an internal sediment screen that fits inside the bung and protruded into the tank a couple of inches?

Good luck, cant wait to see this car.
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Boston Bob E.
www.bimelliott.com www.deserterownersgroup.org

[GS guy]

A little more progress with the tank. Got the baffle design transferred to some 20ga steel and rough-fitted to the tank internals. Fine tuning the fit and adding baffle drainage openings today.

Also working/planning on the vent system. I'm shooting for 1/4" vent lines, hoping that'll be adequate - so please advise if I need to go bigger?

I'm adding a roll-over valve for safety and carbon canister into the system to minimize the gas fumes.
Where almost all buggy bodies have a large opening between the forward bulkhead and hood, I'm fiber-glassing in a continuation piece that will seal cockpit to hood using a rubber seal - and provide a clear vertical surface to mount "stuff". It'll also stiffen up the front fenders/bodywork which have become a little floppy with all the lower bulkhead fiberglass removed to fit my chassis.

Found this compact canister at US Plastics which seems like it will fit the bill. For mounting, this Moroso t-bolt clamp is the right size to fit the 3" diameter (x 6-3/8" long) canister - if a bit overkill. Roll over valve is a '94 Nissan Altima part (PN 1737089900):

Conveniently these are both equipped with 1/4" hose fittings and with limited headroom, the ROV with fittings coming off the side are a good option.

Planning to route the main vent off the new filler neck where it comes out of the tank (but as high as possible while allowing room to fit the short rubber neck to cap hose). This will run up to a Tee, combining the new vent with the original 3/16" vent coming off the corner of the tank. From here into the ROV, mounted high on the new bulkhead, then over to the carbon canister also on the bulkhead. From here the main vent will run high along the bulkhead, then down through the fiberglass to somewhere under the nose and lower on the chassis, with a small inlet filter fitted. There's also a purge fitting on the canister, which the manufacturer shows simply going into an air filter housing. I'm thinking I'll run this back to the engine into the intake tube, just downstream of the filter, or into the air filter housing, final termination TBD.

Jeff
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70's vintage Deserter GS buggy - undergoing transformation to Super GS!

[GS guy]

Internal baffles fitted and ready for welding in. Man - that was a lot of holes to punch! Chassis punches make it easier, but lots of time.

After another look at the top-half of the tank and contemplating the original filler and big vent hole I need to plug, I'm second-guessing my original ideas on venting the tank from the fill neck. That original big vent hole looks like it would make an ideal spot to locate my main vent, and will readily take a 3/8" NPT bung with some minor tweaking. That could serve double duty as a drain for the tank liner as well.....

Red Kote seems to be a popular tank liner and recommended my many, so will probably be what I'll use. Just wondering how well I'll be able to coat all the new baffling inside. Maybe double the amount to make sure I've got plenty to slosh around? Sounds like it'll be a workout!

No welding today, a bit too breezy and time to catch up on some football.
Jeff
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70's vintage Deserter GS buggy - undergoing transformation to Super GS!

[joescoolcustoms]

Be careful of your venting placement. If the fuel level gets above it and the end of your hose is below it, a slight pressure from warming fuel will start a siphon and dump the contents down to the vent level.

I only run vented caps so the vent comes from the highest place on the tank and not subject to the siphon effect.
_________________
Bad News Racing 2018 NORRA 1000 3rd in Class
Best Day Ever Racing 2022 NORRA 1000 2nd in Class and first All Female team to complete the race

Everyone is gifted. Some just do not open the package.

Looks like it was painted with a live chicken,polished with a brick and buffed with a pine cone

[GS guy]

Thanks for the venting tips Joe. I looked closer at the aero-cap, not really a good way to locate a vent up near/just under the cap. The original tank (to OEM filler neck) vent location should end up the highest point on the tank, even higher than the original (new) filler neck location I was planning - where the neck/tube meets the tank. There should still be plenty of expansion room in the tank, similar to stock, and the ROV will be up just under the hood, near the filler cap height.
I've re-thought the vent line sizing and now decided instead to go with 5/16" hose size. My Suby motor could draw a surprising amount of fuel under full boost - want to make sure I've got plenty of ventilation flow for make-up air in the tank as my EFI pump is gravity fed. Now going with a Tanks, inc. ROV and have modified the carbon canister to accept a 1/8NPT for the tank vent line. I think 1/4" would be plenty for a VW motor, but maybe marginal for the Suby.
Jeff
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70's vintage Deserter GS buggy - undergoing transformation to Super GS!

[GS guy]

Man - switching to a 5/16" vent line size sure opened up a can 'o worms! I can see why most folks just vent through the cap. Never being one to take the "easy" route when a much more challenging one presents itself (usually the result of a "this seems like a good idea" thought process) - I dove in head first!

One thing I found that might be helpful to others - the 5/16" hose barb size is primarily used in the automotive market, with slim pickings in that size at your local hardware establishment. I identified a Dorman 5/16" barb to 1/8MNPT fitting that would get me through - generally available at most FLAPS. Also found a 5/16" Tee fitting that I was planning to use - but as the process moved forward it got shelved for other ideas:

(BTW - McMaster also has most of these fittings - but typically come in boxes of 10 or so, and I didn't need a bunch of specialized fittings I'd have to store, plus the extra cost involved.)

Picked up a Tanks Inc. roll over valve:

So the ROV uses a 1/4MNPT fitting on top, that a venting cap screws to. What I needed to do was modify the ROV to have side-exit fittings like the Nissan valve I was originally going to use, as the ROV needs to be mounted vertically and as high as possible under the hood. I'm also combining the original 3/16" tank vent with a new 5/16" vent on the passenger/rear corner of the tank, so I needed a Tee fitting. Keeping the ROV as close to the underside of the hood as possible, a short stack-up was needed between the ROV and fittings. After a bunch of different ideas, I finally distilled it down to integrating it all together, using a 1/4FNPT Tee, 5/16 and 3/16 barb to NPT fittings, and a modified fitting (originally a 3/8" barb to NPT) - with a properly sized hole to press-fit the ROV into. The ROV was modified to size the barb end for press-fit into the NPT fitting. On top, a standard NPT elbow and 5/16" barb suffices.

Here's how it came out. Modified ROV with top fittings:

Parts ready to be assembled:

And assembled:

Since I'm venting through a carbon canister (I hate gas fumes!), I had to modify the "tank" inlet to use a 5/16" fitting. The existing 1/4" fitting was pretty easy to cut off, then drill and tap the boss for 1/8NPT. For the main canister vent - I wanted to run this outside of the upper tank area, so it needed a hose connection too. The tube sticking out for this is 7/16", but I found a 3/8" fuel hose can be wiggled on. From there a size changing barb fitting gets it down to 5/16". This hose will terminate with a small WIX fuel filter on the end, final location TBD.

Here's the modified canister:

Also got the round steel blanks made up to cap the original tank filler and outlet. Now just have to get a decent day (and the time) to start tacking all this together!

Jeff
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70's vintage Deserter GS buggy - undergoing transformation to Super GS!

[bim55]

I'm reallly looking forward to seeing this car completed, but probably not as much as you are.

As always, nice work, , complicated, , but nice.
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Boston Bob E.
www.bimelliott.com www.deserterownersgroup.org

[GS guy]

Thanks Bob! I guess I love complication (or maybe just solving problems I create for myself? )
I am for sure ready to get this car done. I think I missed my goal of getting the chassis ready for paint before Winter, it's setting in pretty quick around here. Just needed a couple more items welded on and then general clean-up, sanding/scuffing, then get ready to shoot some primer. Guess that'll be my Spring-time mission now. Hopefully I can at least get the fuel tank put together up over the colder months and ready to go in when the time comes.
Jeff
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70's vintage Deserter GS buggy - undergoing transformation to Super GS!