Fuel Tank Prep for Install, Should I Pressure Test It Options

[DennisV]

I'm planning to refurb our fuel tank this trip. Should a fuel tank be pressure tested? If so, how the heck do I do that? This is a 914-6 carburetor car, if it matters.

It is out of the car and appears to be in very good shape. It hasn't had anything in it for many years. I would love to think there is some high tech copper coating in the bottom, but I suspect that is surface rust. I am thinking that a couple gallons of Evapo-rust for a few days will solve that. Also provide some evidence if there are major leaks. Then probably fog it with Sea Foam, since it will probably be months before it's actually attached to the engine.

Anything I'm missing before it would go back in the car?

[Montreal914]

Could it be just old fuel varnish? Seems a bit shiny for being rust.

Tank looks very clean otherwise. I would replace the sock at the fuel line pickup.

[Dave_Darling]

914 fuel tanks are not pressurized--the whole charcoal canister system is there to prevent that.

Leak test it; you can put whatever liquid you like in it, plug the outlets on the bottom of the tank, and see if there are any pinholes. The areas where the tank sits on the felt pads in the body are prime spots for them.

--DD

[930cabman]

914 fuel tanks are not pressurized--the whole charcoal canister system is there to prevent that.

Leak test it; you can put whatever liquid you like in it, plug the outlets on the bottom of the tank, and see if there are any pinholes. The areas where the tank sits on the felt pads in the body are prime spots for them.

--DD

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the fuel tank is not pressurized in service, why now? If it's not showing any signs of heavy rusting, clean it up and drop it in

[fiacra]

Could it be just old fuel varnish? Seems a bit shiny for being rust.

Tank looks very clean otherwise. I would replace the sock at the fuel line pickup.

(IMG:style_emoticons/default/agree.gif) Just looks like varnish. From what I can see I would simply clean it with Por15 cleaner/degreaser. I only needed a quart (link below). I did that with my Super Beetle tank that had been sitting for 16 years. It looked in similar condition to yours (again, from what I can see) and it cleaned up just fine. I wouldn't clean the tank until just before you are ready to install it and put fuel in it. If it sits for a while you could get light surface rust. If it is going to sit for a while make sure you seal the openings well and keep it in a warm dry place. After cleaning I used a hair dryer to make sure the inside of the tank was as dry as possible. There are more than a few videos about this on-line, some good, some done by idiots. You'll quickly figure out which is which (I woudn't, as an example, dump out the cleaner on my front lawn when I'm done).

https://por15.com/products/cleaner-degrease...Z4jySTdOJuFFBmb

[DennisV]

Just looks like varnish. From what I can see I would simply clean it with Por15 cleaner/degreaser. I only needed a quart (link below). I did that with my Super Beetle tank that had been sitting for 16 years. It looked in similar condition to yours (again, from what I can see) and it cleaned up just fine.

Thanks for the suggestion. POR-15 will clean varnish? I am not seeing that application in the product description, but it sounds like you have first hand experience. Did you dilute it? They are saying "can be diluted with water up to 4 to 10 times its volume".

Thank you.

[fiacra]

Just looks like varnish. From what I can see I would simply clean it with Por15 cleaner/degreaser. I only needed a quart (link below). I did that with my Super Beetle tank that had been sitting for 16 years. It looked in similar condition to yours (again, from what I can see) and it cleaned up just fine.

Thanks for the suggestion. POR-15 will clean varnish? I am not seeing that application in the product description, but it sounds like you have first hand experience. Did you dilute it? They are saying "can be diluted with water up to 4 to 10 times its volume".

Thank you.

Says right on the front of the container that you can use it to clean fuel tanks. It definitely cleaned the old varnished fuel out of my SB gas tank. I did use some loose chain on the inside to help clean while I was agitating it. Some people use washers or screws, but I was afraid I wouldn't get them all back out again. I diluted it with hot water about 4-5:1. You can do use a less dilute concentration if your tank needs it. Mine was worse than yours and it only took one bottle. Can't remember how long I turned and agitated the tank for, but I do recall how tired my arms were afterwards. I think I just bought a set of stoppers on Amazon to seal the openings in the tank while I cleaned it. Search for some videos, they will be helpful. Here's a link for one as an example. This is just from a quick search.

https://www.youtube.com/watch?v=2JoHRfmrTes

NB: I strongly recommend using proper protective gear such as safety glasses, gloves, etc. At least he wasn't wearing flip-flops!

Just to be clear, I'm not recommending the full POR 15 fuel tank "restoration" kit. Plenty of well documented examples of the sealer failing and then clogging the fuel system. I'm just recommending the cleaner, and not the etcher and sealer. You can buy the cleaner separately.

[Superhawk996]

Just looks like varnish. From what I can see I would simply clean it with Por15 cleaner/degreaser. I only needed a quart (link below). I did that with my Super Beetle tank that had been sitting for 16 years. It looked in similar condition to yours (again, from what I can see) and it cleaned up just fine.

Thanks for the suggestion. POR-15 will clean varnish?

Thank you.

I’ll beg you not to put POR-15 (paint) or any sort of sealer inside the tank.

Hopefully a typo and you’re thinking of POR Metal Prep. I have used POR Degreaser & Metal Prep to remove surface rust from tank internals. It leaves a light coating of zinc phosphate which helps prevent flash rust when used according to the directions.

[Superhawk996]

Just to be clear, I'm not recommending the full POR 15 fuel tank "restoration" kit. Plenty of well documented examples of the sealer failing and then clogging the fuel system. I'm just recommending the cleaner, and not the etcher and sealer. You can buy the cleaner separately.

(IMG:style_emoticons/default/agree.gif) with avoidance of sealer

I’ve used the metal Prep with good results. No issue with that product. Just don’t seal it.

[fiacra]

Just to be clear, I'm not recommending the full POR 15 fuel tank "restoration" kit. Plenty of well documented examples of the sealer failing and then clogging the fuel system. I'm just recommending the cleaner, and not the etcher and sealer. You can buy the cleaner separately.

(IMG:style_emoticons/default/agree.gif)

@Superhawk996 So you recommend using the POR Metal Prep after the cleaner/degreaser? I didn't do that when I cleaned my tank. It looked pretty clean, I wasn't going to use a sealer, and I didn't know it was recommended to do after cleaning the tank even if you weren't going to apply a sealer. Just like to know if I missed a step I should have done.

And again, to be absolutely clear, I'm NOT recommending resealing a tank with POR Sealer or any other product. I know that's what he was doing in the video I posted a link to, but the purpose of posting that link was just to watch the first part of the video where he starts to clean the tank, and to show that any fool can post a video (IMG:style_emoticons/default/stirthepot.gif) I've read enough of the horror stories and replacement tanks are available for a reasonable cost so why reseal an old tank? But if the tank just needs cleaning after sitting for a while it seems reasonable to do that.

[Superhawk996]

So you recommend using the POR Metal Prep after the cleaner/degreaser? I didn't do that when I cleaned my tank. It looked pretty clean, I wasn't going to use a sealer, and I didn't know it was recommended to do after cleaning the tank even if you weren't going to apply a sealer. Just like to know if I missed a step I should have done.

I wouldn’t worry about it. @fiacra

The degreaser is basically potassium hydroxide - a strong base, that dissolves grease/oil/varnish. If that’s all it took to get your tank clean that’s awesome.

The metal prep just does a good job of removing the light surface rust and then leaves a bit of zinc on the metal to prevent flash corrosion. In my case I had some decent rust residue in my tank after the degreaser and the metal prep took care of that.

Like you, I despise sealer having seen it fail on two occasions on other projects. If a tank needs sealer just buy a new tank. On other motorcycle projects where the tank couldn’t be replaced I’ve had to weld the tank to repair. Trusting sealer to fix those sorts of problems is just foolish.

Keep the gas tank full of non-ethanol gas during storage and have never had a problem with re-rusting.

[porschetub]

914 fuel tanks are not pressurized--the whole charcoal canister system is there to prevent that.

Leak test it; you can put whatever liquid you like in it, plug the outlets on the bottom of the tank, and see if there are any pinholes. The areas where the tank sits on the felt pads in the body are prime spots for them.

--DD

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the fuel tank is not pressurized in service, why now? If it's not showing any signs of heavy rusting, clean it up and drop it in

(IMG:style_emoticons/default/agree.gif) clean it and use it ,cheers