Upgraded Fuel Tank

Does anyone on here have the optional "upgraded" fuel tank that Classic Roadsters sold? I think it was 20gal?

I've been looking at replacing my fuel tank for something with more capacity. And while having one of my long morning-coffee-fueled reflections, had a strange thought... but I need someone that has a tank to confirm.

First question would be: is the tank made of steel or not?

David

I had the 12 gallon Chevette tank as well that suffered from a few issues. First the 12 gallon capacity limited traveling range . Second it is not internally baffled so the fuel gauge bounces all over as the fuel is drawn down and third...it leaked. Did a fair amount of searching and never found anything that would fit the MX while increasing capacity. Since the winter I have been extensively modifying the suspension so I've spent a lot of time under it and noticed some dead space available between the top of the OEM tank and the bottom of the trunk.

Ultimately I made up shop drawings for a new aluminum tank that is a little wider than the OEM with a second tier that would occupy some of the space above. There are (3) baffles inside so as to limit slosh and hopefully the dancing gas gauge. Capacity came in at about 16 gallons.

I am using .072 5052 H-14 material and designed it in such a way as to have (4) outside components to weld up with the (3) baffles within. The tank will fill from the original location and into the lower tier of the tank. For that to work when filling the tank, I have provisions to vent the upper tier of the tank back to the filler neck. There is a secondary vent atop the upper tier that will vent to the upper wheel well terminating in a "roll over" vent. That vent will allow air to enter the tank as the fuel levels drops.

Hotrod got me going on this and he has already built his tank in a similar configuration although his is designed for fuel injection as well.

The aluminum is on order and once it arrives I'll cut and bend up the various components. My airport buddy is a talented aluminum welder so no worries there. Ill post the cost of materials and fittings once the aluminum sheet arrives.

Thanks for the info DrJ! When you get working on that tank, would love to see photos!

I contacted Sebring International this morning because I noticed they stated their fuel capacity as 60L (about 16gallon) and thought they might have used some british donor vehicle we could source from. Unfortunately they make their tanks in-house (out of stainless steel ooooh) and could sell me one for 775GBP which is out of my budget (not to mention shipping costs).

David, I have a drawing for the CR big tank.  I can't remember if it came form here or the old site, so it might already be on here somewhere.  It's in PDF form.  How do I upload the file?

My tank dimensions wouldn't help anyone since my rear suspension is totally non-standard.  It's only about 15 gallons due to interference with the upper 3rd link.

The 5052 alloy DrJ listed is what I used in mine.  It is recommended for marine fuel tanks.  I was concerned about the ethanol in modern gas and it's propensity to attract moisture.  This can lead to internal corrosion. Probably not an issue if you drive your car regularly and keep fresh gas in the tank.  If most folks are like me, my toys sometimes sit for longish periods.  Since the 5052 is designed to live in a salt water marine environment, it should do well.  I used 1/8" thick material to make welding a little easier, but my tank will be heavier that J's.  I had considered stainless, but it would have been very heavy. That weight would have been hanging out behind the rearend and would have upset good front/rear balance.

I used the 2 step tank configuration that DrJ described to make the tank shallower.  This helps with running exhaust.  The oversize CR tank is very deep near the rearend and tapers up toward the rear of the car.  A car with side pipes like yours wouldn't need the extra room.

To answer your question, I have a MS Word document that has several pics of the big tank.  Most of the pics appear to be of an aluminum tank, but one shows the tank painted.  This may indicate that it was available in either material.  I'm not sure why you would paint an aluminum tank.

I'll see if I can convert those pics to something I can link to. You might be interested in seeing them.

Here they are.

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More.

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I'm not sure the vent line is large enough to allow quick filling.  I guess it is since there are a lot of these in service, but I would make it larger.

That is an awesome reference point! Thank you.

I moved all the documents from the old site onto here and never saw one for a gas tank...
If you have it and can send it to me i'll upload it

Hmmm, I have what appears to be a stock type tank from some car...no idea what its from though. Did not see a receipt for it. No idea if its from a particular car, but modified or stock. It seems pretty big too, but the gauge doesnt read correctly, so I'm afraid to try and let it go empty just to find out how big it is.

@aronhk: Most likely a 12 Gallon Chevy Chevette Tank. That was the specified donor part in the build manual. They don't give you too much range though.

You're right, 12 gallons isnt big.  Guess I'll find out one day.  I think I am going to purchase a fitech EFI setup for it.  Right now in fifth gear at 60 I seem to be around 1900 rpm, so I'm thinking I may be able to hit 20+ mpg with it.

Yeah the highway mileage is always good, especially with a 5-speed. If you have a carb though it fouls the plugs pretty fast revving that low for hours...always an excuse to put your foot in it once in a while

Thats why the new EFI systems are so wonderful. They are self learning and can keep the A/F ratios right where they are supposed to be far better than a carb can. Better fuel economy and the engine runs better. And the prices have seriously come down almost into the quality carb range. I won't get to it right away, but when I do I'll post how it goes here.

Here are dimensions of a tank of a friends about a month before he passed away.

[url=https://www.dropbox.com/s/3665mmfw7mfyqso/19-Gal Gas][You must be registered and logged in to see this link.]