more gas tank questions....

[Bentley]

Ok, the new Z has been sitting for 13 years. (Garaged)

I drained the gas, all that i could, and even shot a screwdriver through the drain hole to dislodge and gunk that might have stopped up the hole. However, to my surprise, the tank still seemed to be holding another quart or two of gunky liquid in a section of the tank that would not drain. So, I dropped the tank and poured the gunk out the fill tube. I think the liquid was trapped in the top. Some REALLY nasty looking stuff came out.

THen...I washed the tank out, best I could. When looking in the fill hole with a flashlight, I was surprised that that cavity seemed baffled from the rest of the tank. I could not see how the first few gallons of gas could get to either the pick up, or the drain plug. What am I missing? can anyone explain the basics of the interior of the gas tank on a 2/70 240Z?

Ben

[tanny]

When I looked into my tank, I'm pretty sure the baffle has some clearance underneath it so the gasoline will be baffled but can still move to either side of the baffle. Victor.

[Bentley]

THanks.

I blasted it pretty good, but will try again to break through the crud.

Any idea about the top lobe of the tank? Does this normally also drain into the "lower" part of the tank? This one also seems to be trapping fluid.

I kow that sounds stupid, buy hey, someone here has to be an idiot and I feel as though I have found my calling.

Ben:stupid:

[LanceM]

Just cleaned mine after 15years sitting. About the same situation. Remove the sending unit for the gas gauge and you will have a lot better shot at cleaning it out. I sprayed mine everyway I could with a power washer then dumped a half gallon of muriatic acid in it and let it sit for about an hour gently stirring the tank around every once in a while. Then I connected a garden hose to the vent on the drivers side of the tank and flushed it for about 30 minutes. Came out looking like new inside, I started with about a half inch of really nasty smelling gunk on the bottom to start with

[Daniel]

A friends dad was doing an old tank.He put whatever cleaner in it,put some large rocks in the tank,sealed all the holes,Strapped it on the hood on his riding mower and cut his yard,turning it every so often to a different angle.When he finished it was polished on the inside!!The vibration and the stones did a great job.Just make sure the size cant get hung in those baffles and make sure you get out the same number you put in.

[kmack]

Lance,

Make sure you nuetralize the muratic acid!

I did this same thing to my tank years ago. Came out almost looking polished inside. It was great. I rinsed it out for over an hour with water thinking that would be enough to stop the acid.

It wasn't. 2 months later I had a clogged fuel filter. A little over a month later after that, and I was changing fuel filters again. Appearently, water alone will not nuetralize muratic acid. You need to use something like baking soda or an actuall acid nuetralizing agent. I ended up tanking my tank in to have it professionally cleaned and dipped.

[LanceM]

Thanks for the heads up, I'll flush it with some soda real good.

Lance

[26th-Z]

POR makes a gas tank sealant and I think they sell a cleaning kit also. You may want to consider sealing a tank that got nasty.

[Bentley]

Hey,

thanks for all these ideas, sounds hopeful.

What is POR?

Village idiot,

Ben

[BlueZee]

Here is the link:

http://www.por15.com/

Regards,

Les

[Bentley]

thanks les. I'll check it out.

Village Idiot has a dozen more questions....

1) I'm still puzzled how 1/3 of the capacity of this tank is ABOVE the fill tube. Did anyone else experience having gas trapped up there? is it simply a baffled area, and my connecting "drain/fill" holes are clogged? Sorta like the lower lobes had crudded themselves into being completely seperate?

The way the lower lobes were clogged, I drained all the gas out of the drain hole, but still had lots of gas trapped in the side section(s). One section drained slowly for an hour and another section, somewhere, did not drain at all.

2) It strikes me that a) since this crud does not appear to be rust, it is perhaps residue picked up in the tank through all the "vapor" return lines, perhaps post-combustion. if so, how can all of us catch this crap BEFORE it gets to a final resting place in the tank?

3) Does Muratic acid destroy the fuel guage float, or did you remove it? Does it come out with the entire sending unit? (I'm currently 250 miles from home and my tank, or I'd look.)

4) Without a doubt, this tank could not possibly have given relyable gas reading on the guage. In fact, the center section where the pick up is could be empty, and the side section where the float is have a few gallons..........thus leave an unsuspecting redneck like me stuck somehere. Just an observation i guess. For those who might be driving and having intermitant fuel guage tom-foolery.

5)Last question, is it adviseable to go ahead and replace the sending unit and float, just to keep from having having to take "two steps back"? Do they go out easily, or are they tough as nails?

One day.......I'll be a fuel tank expert.

"Z" Village Idiot :stupid:

Ben

[Victor Laury]

The Village Idiot asks good questions.

1 & 2) I'd say that your observations confirm you need to clean the tank!

3 & 4 & 5) the sending unit is not hard to remove and replace, especially while the tank is out. I would not expose the sending unit to anything other than gas, which is nasty enough!

I'd stay away from acid treatment altogether, as I belive it will cause you more grief in the future. This is one of those tasks you really don't want to do twice.

I know everytime someone asked about tanks, I suggest Tank Renu service. You guys might think they pay me or something. Nope. They impressed me with their warrenty. With service like that, It's worth a little more for a gas tank for life.