New Aluminum Fuel Tanks

[thescifiguy]

Who wants a new fuel tank?

I'm going to take my GT's fuel tank to a local marine tank maker to have a directly installable aluminum copy made of it. It will be made of 1/8" thick
5025 alloy that is then pressure tested and coated with epoxy. All of the Fill, Vent, Outlet, Sending Unit, and Mounting holes will match up. Standard fittings of your choice will be able to be screwed into the Vent and Outlet locations. The unit will have square welded edges rather than the rounded stamped steel edges we currently have. The seam flange that currently sticks out all around the sides and has the mounting holes in it will be eliminated and L-brackets or a piece of aluminum angle material will be welded to the sides to match the tank mounting ledge in the car. The tank will have baffles inside to prevent sloshing and maintain stable fuel level.

The company says the likely cost will be between $400-$500. No modifying of your car. Spare tire area remains unchanged. Same tank volume. No monkeying together all the parts to adapt a fuel cell as a replacement tank and the accompanying loss or reconfiguration of the spare tire ledge. No hit-or-miss luck with trying to have your stock tank lined with urethane. Upgrade to a 3/8" or larger fuel outlet. The possibilty of installing syphon-type in-the-tank fuel pumps presents itself, too.

Because most of the cost seems to be the aluminum, the owner said that there's not likely to be much of a difference in price whether I order one or twenty. Once he creates mine, he'll then have the dimensions on file to create others as needed. I have no financial interest in this other than to get several tanks made for my GT's at the best price and quality and to have them go in with no fussing and modifying. The company is Atlantic Coastal Welding in Bayville, NJ 800-434-8265.

I'm going to pull my '72 tank out today and drop it off soon, anyone who might be interested in these tanks can send me a message or add their info to this thread. My # is Gordon @ 856-477-2119 and thescifiguy@juno.com. I'll be out of commission for almost two months starting 10/25 till 12/15 because my Post Office job is sending me out to Oklahoma for job training.

There's always a glitch or two when having something like this done and my first tank will serve as the quinea pig. Here's a couple of questions I have:

1) Are those cylinder-type Chevy fuel sending units that I see in the Summit catalog compatible with our GT gauges and wiring? I need to know if the company has to specifically make the tank to handle an Opel unit or if other more commonly available ones will work. I'm open to other types of sending units, as long as they'll install and work with a minimum of fuss.

2) Are there any other parameters or options I've overlooked? Help me out guys, I'm no motorhead, just a 30 year GT-only guy, I don't have much experience with the other possibilities that are no-doubt out there.

I'm not locked in to this deal and I'm still open to other options or places to send my business. I've had 5 GT's in my life and they ALL bedeviled me with clogged fuel filters due to corroded gas tanks. I've searched the threads and started one or two of my own on this subject and the silence is deafening in regards to tank replacement. With our cars being 40 years old I'm sure we've all got issues with our stock tanks and I'm really surprised that I can't find a well-trodden path to a simple solution that bolts right in and off you go.

Your thoughts and interest greatly welcome,
Gordon

[neuropel]

Question - will the aluminum tank perform the same in the event of a rear-end collision? If so, I think you're on to something, especially if there are other sender options. I have a GT that is in need of a tank repair as well, and up to now I've been planning to go back to these guys. They're located about an hour from me in PA, so I had an opportunity to visit and see their facility. I had them refurbish two Manta tanks and they are guaranteed for life. It would likely be cheaper, even with shipping, to have them refurbish your tank versus having a new tank fabricated, especially if your tank is not TOO bad. They basically split the tank in half, blast everything, repair any metal damage (regardless of how extensive), and then reassemble and coat. They will install whatever baffles or fuel line fittings you want as well, at minimal cost. I have no financial interest in them, just throwing it out there as an option. I'm a satisfied customer.

[thescifiguy]

Well, that's the problem: "if your tank is not TOO bad", isn't it? There's no way to really tell. Yeah, you can get the mirror on a stick and flashlight and try to look for rust in the baffles, but I'm sure most of us don't want to get that intimate with our tanks. It's bad enough just getting them in and out. Plus, even if your car spent most of it's time frozen in Alaska, it's still had FORTY YEARS worth of gas eating at it.

I got this car running for the first time in 18 years about 4 months ago. The first thing I did was have the tank cleaned and lined. Yeah, the guy said it was pretty bad and that he lined it with two applications of the urethane stuff. I looked inside before installing and it looked massively coated in the stuff. I just took it out 5 minutes ago and there's about a half a cup's worth of black sandy rust sloshing around in it. The car hasn't even gone through 5 full tanks of gas, yet!

On a related note: At the time I had the tank relined, I'd also acquired a brand new in the box sending unit. I took it apart to see what a new one is supposed to look like and it had a nice chrome-looking center shaft with the two slender wires in either side and shiny brass bushing for everything to slide on. About two months after I got the car running I noticed that the fuel gauge wouldn't go past 3/4 full, even with the gas in the tank so full you could SEE it with the cap off. I took out the sender, slid off the cover, and the center shaft was already rusted and pitted and binding the float thingy. Maybe the leaded gas from the 60's and 70's inhibited rust, I don't know. Either that or modern gas is HIGHLY corrosive!

Considering that a new Opel radiator from OGTS is $550, $4-$500 for a tank that'll NEVER rust and could even be resold or reused long after your car bites the dust sounds like an okay deal to me.

Anybody have any thoughts about the corrosiveness of leaded gas and today's blends?

[neuropel]

The repair I'm recommending is FAR more than the typical pour-in urethane solution. I was referring to a patented process were the tank is coated and baked at 350-400 degrees...multiple times. They wouldn't offer a lifetime guarantee otherwise.

[thescifiguy]

What did they charge to redo your tanks?

[neuropel]

I can't recall exactly, but it was under $300 for each tank. I had them alter the tanks so that I could use either type of Manta sending unit ('75 or pre-'75), and I also had them add baffles and feed/return lines for fuel injection. Unfortunately I'm not at home or I'd show you pictures. I'd recommend taking the time to go through their website (it's a bit quirky, but the info is there). The pricing depends on how much metal work they have to do to your tank. As you can see in their pictures, they can repair tanks in AWFUL condition.

On your sending unit, it is likely that the resistance range is 0-90 ohms like most other GM sending units (check out Steven's (oldopelguy) post in this thread related to Manta senders), so you might want to dig into that a bit further if you're interested in finding a more robust sender. That thread is referring to Manta senders, but I'd say odds are good the GTs operate in a similar range. I too would like to find something better (or rather, more common/easy to replace) than the original GT sender. If you find a good solution, by all means post it here. The Gas-Tank folks can modify the tank for any sender once they have it, and it would likely add only minimal cost.

It just occurred to me that if new aluminum tanks can be fabricated for $400-$500, I wonder why Opel GT Source hasn't bothered having some made? I'd say they get a LOT of requests for them.

[thescifiguy]

Considering how much trouble I've had and the frequency with which "barn finds", probably with funky tanks, show up, it's a wonder that we haven't come up with a low-hassle replacement tank option.

Maybe it's because the tanks are hidden away back there. Outta sight, outta mind. It's much more fun to spend money on the stuff you can see like wheels, paint, and all those engine possibilities.

I thought I was crazy to make my first repair on the car a $200 tank cleaning and reline. At this point, I'll spend just about anything to make this problem go away and never ever come back.

That point you made about fuel return lines for fuel injection was a good one. I'll add that to the list.

[opelnut10]

Originally Posted by thescifiguy Well, that's the problem: "if your tank is not TOO bad", isn't it? There's no way to really tell. Yeah, you can get the mirror on a stick and flashlight and try to look for rust in the baffles, but I'm sure most of us don't want to get that intimate with our tanks. It's bad enough just getting them in and out. Plus, even if your car spent most of it's time frozen in Alaska, it's still had FORTY YEARS worth of gas eating at it. I got this car running for the first time in 18 years about 4 months ago. The first thing I did was have the tank cleaned and lined. Yeah, the guy said it was pretty bad and that he lined it with two applications of the urethane stuff. I looked inside before installing and it looked massively coated in the stuff. I just took it out 5 minutes ago and there's about a half a cup's worth of black sandy rust sloshing around in it. The car hasn't even gone through 5 full tanks of gas, yet! On a related note: At the time I had the tank relined, I'd also acquired a brand new in the box sending unit. I took it apart to see what a new one is supposed to look like and it had a nice chrome-looking center shaft with the two slender wires in either side and shiny brass bushing for everything to slide on. About two months after I got the car running I noticed that the fuel gauge wouldn't go past 3/4 full, even with the gas in the tank so full you could SEE it with the cap off. I took out the sender, slid off the cover, and the center shaft was already rusted and pitted and binding the float thingy. Maybe the leaded gas from the 60's and 70's inhibited rust, I don't know. Either that or modern gas is HIGHLY corrosive! Considering that a new Opel radiator from OGTS is $550, $4-$500 for a tank that'll NEVER rust and could even be resold or reused long after your car bites the dust sounds like an okay deal to me. Anybody have any thoughts about the corrosiveness of leaded gas and today's blends?

The biggest problem is modern gasoline, it contains ethanol (alcohol) which will pull moisture out of the air and water is heaveier than gasoline so guess were the stuff settles at (bottom of the tank) That leaves the question, "what do I do about it". Several products on the market will act as a "dryer" if the car is driven on a regular basis. If it sits up and is only driven once in a while the tank needs to be coated, made outta stainlees, aluminum or replaced with a fuel cell that has a bladder inside a steel can.

[Dale .D]

How about the elaborate venting system ?

I'm going to take my GT's fuel tank to a local marine tank maker to have a directly installable aluminum copy made of it. It will be made of 1/8" thick 5025 alloy that is then pressure tested and coated with epoxy. All of the Fill, Vent, Outlet, Sending Unit, and Mounting holes will match up. Standard fittings of your choice will be able to be screwed into the Vent and Outlet locations. The unit will have square welded edges rather than the rounded stamped steel edges we currently have. The seam flange that currently sticks out all around the sides and has the mounting holes in it will be eliminated and L-brackets or a piece of aluminum angle material will be welded to the sides to match the tank mounting ledge in the car. The tank will have baffles inside to prevent sloshing and maintain stable fuel level. The company says the likely cost will be between $400-$500. No modifying of your car. Spare tire area remains unchanged. Same tank volume. No monkeying together all the parts to adapt a fuel cell as a replacement tank and the accompanying loss or reconfiguration of the spare tire ledge. No hit-or-miss luck with trying to have your stock tank lined with urethane. Upgrade to a 3/8" or larger fuel outlet. The possibilty of installing syphon-type in-the-tank fuel pumps presents itself, too. Because most of the cost seems to be the aluminum, the owner said that there's not likely to be much of a difference in price whether I order one or twenty. Once he creates mine, he'll then have the dimensions on file to create others as needed. I have no financial interest in this other than to get several tanks made for my GT's at the best price and quality and to have them go in with no fussing and modifying. The company is Atlantic Coastal Welding in Bayville, NJ 800-434-8265. I'm going to pull my '72 tank out today and drop it off soon, anyone who might be interested in these tanks can send me a message or add their info to this thread. My # is Gordon @ 856-477-2119 and thescifiguy@juno.com. I'll be out of commission for almost two months starting 10/25 till 12/15 because my Post Office job is sending me out to Oklahoma for job training. There's always a glitch or two when having something like this done and my first tank will serve as the quinea pig. Here's a couple of questions I have: 1) Are those cylinder-type Chevy fuel sending units that I see in the Summit catalog compatible with our GT gauges and wiring? I need to know if the company has to specifically make the tank to handle an Opel unit or if other more commonly available ones will work. I'm open to other types of sending units, as long as they'll install and work with a minimum of fuss. 2) Are there any other parameters or options I've overlooked? Help me out guys, I'm no motorhead, just a 30 year GT-only guy, I don't have much experience with the other possibilities that are no-doubt out there. I'm not locked in to this deal and I'm still open to other options or places to send my business. I've had 5 GT's in my life and they ALL bedeviled me with clogged fuel filters due to corroded gas tanks. I've searched the threads and started one or two of my own on this subject and the silence is deafening in regards to tank replacement. With our cars being 40 years old I'm sure we've all got issues with our stock tanks and I'm really surprised that I can't find a well-trodden path to a simple solution that bolts right in and off you go. Your thoughts and interest greatly welcome, Gordon

[thescifiguy]

I haven't dissected a tank to find out why there's 3 places for vent hoses to go to, but I would think that a simpler set up would be possible. I guess it has mostly to do with the baffles and the function they serve. I gather that modern tanks have plates or foam walls in them to reduce sloshing and keep the fuel level fairly stable for the sending unit and other reasons? Or are the baffles there to create an air pocket for the vapor to collect.

For either reason, since the new tank will be flat plates of aluminum welded at mostly right angles, I would think that a single plate welded all across the top of the tank, forming a pocket and a single well placed vent outlet ought to do it. There'll have to be a hole in it for the sender to stick down and maybe a little finesse where the fill tube is.

As far as I know, the company will try to make a fairly exact copy. They're the experts in gas tanks, not me. I'm gonna try to drop the tank off tomorrow and they'll evaluate the situation and tell me what's what. I, too, had been thinking about a simplified venting system. I'll mention it to them.

[baz]

iirc baffles are added to a tank to hold fuel near the pick up when doing hard cornering/accelerating /braking so you dont lean out an engine and also iirc opel dont fit them normally in our cars for cost reasons ( bean counters were at work in the sixties too ) or at least i cant remember ever seeing any in my gt or manta tanks i think they had more of a sump to hold fuel when adding "G" to the car but its been a long time since i looked in one


as far as gt fuel tanks and rear end shunts go i thought the GM/opel recommendation from new was see a dentist on a regular basis to keep your records up to date as the cargo area /wheel cover does nothing to stop gas coming into the passenger cell when the tank splits so it makes identification soooooooo much easier when the fire is put out after all the tank does not need to split as the filler pipe can pop right out as the rear folds + the 3 way sprinkler system , sorry vent system will spray you anyway

[hrcollinsjr]

Originally Posted by thescifiguy I haven't dissected a tank to find out why there's 3 places for vent hoses to go to, but I would think that a simpler set up would be possible.

Common sense tells me that they are there to help prevent air pockets when filling the tank but I've been wrong before.

Harold

[RallyBob]

Originally Posted by thescifiguy For either reason, since the new tank will be flat plates of aluminum welded at mostly right angles

I wonder how much capacity will be lost, as the OEM tank is fairly form-fitted to the floorpan of the car. Seems to me making the tank from multiple pieces of flat means that certain 'low' areas will have to be bridged, which might lessen the fuel capacity.

Not saying the idea is a bad one (every GT needs a tank these days!), but it's going to be quite a bit of work to make everything fit well.

Just curious who is going to be liable should a forum member have an accident and the tank splits at a welded seam?

[thescifiguy]

Just dropped the tank off. The company seemed VERY capable and well-established. Big plant with lots of giant equipment and very serious, smart looking, old guys(like me) busy everywhere. Had to wait in line behind 3 different customers who each were having racing boat tanks made. I had all sorts of notes and diagrams about which measurements were critical, along with the questions some of y'all posed. He looked at them all and handed them back saying "Don't worry, I'll make an almost exact copy of your tank."

So, I'm feeling pretty confident. He also thought that the elaborate vent and baffle system was because "they must've had a hard time filling the tank." His only question was whether the mounting location for the sender HAD to be recessed. I said that since the top of the tank is mainly for vapor, he could lower the height of the tank(the distance from the support flange to the top of the tank) so that the sender can mount along the same plane as the rest of the top of the tank. This will make the top of the tank stop about 1/2" short of the plywood tire support platform. Since the platform is supported on the sides by rails and front and rear by the support pillars, it shouldn't sag in the middle. I don't carry a spare back there, only a big tool kit, but I could glue a piece of wood with a felt pad on it to fill the space and support the middle of the platform like the original tank does.

I'll post pics and let y'all know how things go in a week or so.

[thescifiguy]

"who is going to be liable should a forum member have an accident and the tank splits at a welded seam?"

Good question, I guess there's a "not responsible for damage due to accident clause". Who's responsible for any repair or modification you do to a car or even if Opel's lack of any tank protection back there causes an injury? If you put a turbo on your 1.9 and it blows the head off your engine and clunks someone in the head, are you responsible? I, therefore, make this disclaimer:

I, Gordon Payton, claim no responsibility for damage incurred if you have a tank made by Atlantic Coastal Welding. Purchase and use of said tank is entirely at your own risk.

As far as tank volume, I told him it would be okay if the some of the measurements were shrunk to assure clearance of body parts. My present tank holds 2 extra gallons because the baffles are almost totally gone.

[markandson]

The plywood tire shelf does sit on the tank, the original tank had that "hairy" stuff on it in three strips as anti-rattle insulation between the tank and the wood. If these tanks are to be designed for fuel injection applications then you will need the return line with a dip tube attached to the inside of the return fitting so that when you have a partially empty tank it doesn't sound like a cow peeing on a flat rock, unless you have the radio turned up loud . The original tank also had that expansion bowl in it for those hot summer days when your tank is full. As far as the baffles go you could do what RallyBob suggested a long time ago, and I did in my tank which is to use two or three pickups that are designed to shut off if they become uncovered with gas and then you won't have any starvation problem unless you take the car on a circle track.

[myopels]

Gordon,Why don,t you get a tank made out of stainless steel? That would really be bulletproof. I am a michinist, and have done projects with aluminium. It is soft and wonderful to machine and drill, but eventually it to does corrode to dust. Noyhing is worse than doing all that work and seeing it go to pot. They can use pretty thin CRES to save weight, but it would be even stronger than the alu., and can easily be bent without cracking like alu. A sheet metal shop has benders and all the stuff to make a great round cornered tank with less welding and potential leak spots. gerold

[thescifiguy]

The shop I'm using and another that I'd called said that using stainless for tanks was ILLEGAL. Both were marine shops, so maybe there's a boating law about it. The place I'm using said that stainless cracks and it still rusts.

I'll probably turn to dust before the tank does(Chuckle! Wheeze! Cough!)

[Redskinsjbs]

Does stainless spark?

[thescifiguy]

"Does stainless spark? "

Absolutely. I checked by putting several kinds to the grinder at work today. I think all grades of stainless steel would be considered as a "hardened" steel and hardened steel usually sparks like crazy on a grinder. Aluminum smears. It's a natural bearing, albeit a crappy, short-lived, one. Don't cam bearing sleaves have a thin layer of aluminum on them to aid in break in?

Which brings up the topic all the various grades of metal. Whenever you say "steel" you're actually saying Iron + any number of other things. Even cast iron isn't pure iron. It might have lead plus a whole bunch of impurities. Hardened steel has a lot of carbon. Stainless has chrome and maybe zinc? Or is zinc what turns iron into steel? I know that galvanized steel is just steel with a coating of zinc. In aluminum there's 5000 series alloy, plus 6000, 7000, 8000, etc. They have various amounts of magnesium and other stuff. I've worked with "aluminum" that was so hard and inflexible that the mightiest swing of a giant sledge hammer wouldn't even dent it. And I've worked with steel so flimsy you could tear it like paper. Cast aluminum, like our intakes, cracks, whereas, forged aluminum is very malleable.

Hey, I'm no metalurgest and my knowledge of what's in various grades of metal is cursory at best, as is my knowledge of the properties of all the different alloys out there. You could make a gas tank out of just about anything: fiberglass, copper, brass, pvc, plastic, tree stumps, even cement. As long as it wasn't reactive with the gas and met certain basic requirements.

Which now brings up the subject of what are the basic requirements for an automotive gas tank? Non-reactive with gas and other things that might be dissolved in it, like water, oxygen, etc. You wouldn't want it rock hard because most things like that tend to crack rather than bend. In an accident, you'd rather have your tank dent or even crush, but remain intact. Not too soft, because it's supporting a lot of weight in a bouncing vehicle, plus vibration might get it flexing. Durability, meaning that it won't deteriorate for a decent amount of time, if ever, due to vibration, wear, or corrosion. Workability, meaning that you can actually form a tank out of the stuff to meet all your needs efficiently. Titanium might be the perfect material, but it's a pain in the ass to weld and form and it's really expensive. Lastly, I guess, is affordability and convenience. I wanted a tank made out of a proven-to-work-well material that would exactly match the volume, shape, fittings, and convenience of mounting as my original tank at an affordable price and within a reasonable time.

So I've opted for an aluminum tank made of a 50/50 hard/soft aircraft grade alloy that resists corrosion very well, is workable and has been proven to handle vibration and catastrophe in the aircraft and boat industry, I can just barely afford it, it'll be done in a week, and it should mostly just slip right in.

That works for me!

[hrcollinsjr]

Originally Posted by thescifiguy You could make a gas tank out of just about anything: fiberglass, copper, brass, pvc, plastic, tree stumps, even cement. As long as it wasn't reactive with the gas and met certain basic requirements.

Seems like most of the manufacturers of "modern" automobiles, tractors, lawn mowers, etc. have gone to some type of plastic or POLYMER since "plastic" seems to beneath "their" particular product.

Harold

[thescifiguy]

I picked up the tank and it looks pretty good:

Here's the link to the other pics:
http://www.opelgt.com/forums/members...fuel-tank.html

The mounting holes have yet to be drilled and I have to grab some plumbing fittings for the outlet and vents. The only thing that looks wrong is the angle of the fill neck tube. We'll see how that goes.

I gotta try to get this thing rigged up in a hurry to I can drive to the "Octopelfest 2009" get together this afternoon. I'll have more details and snafu's to relate later in the week.