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Thread: Gunk or something in gas tank!

  1. #1
    1972 240z Decoy12's Avatar
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    Default Gunk or something in gas tank!

    Hello everyone, Z newbie here again requesting help. I got my Z running again although it was running very, very poorly. I bought it back in December and it had been sitting since '03. The previous owner said there was old gas in the tank and so I drained it, filled it back up and after changing everything from the plugs to all the 'pumps' in the engine bay, I ran it for a while. I recently changed my fuel filter because my Z was not running, seeming to be starved of fuel (delayed response when stepping on gas, 'choking' and jerking when I floor it.) Anywho... I was very surprised (not in a good way) when I removed the fuel filter I put back in December, when I noticed it weighed about a quarter pound. Inside there is all this build up of gunk or something. It is brown and it almost looks like modeling clay, although it is soft like a paste, probably because it was mixing with the fuel. I know I need to clean out my tank, but I was wonder if:

    1. Anyone knows what this gunk side is? and
    2. If it would be an easy DIY to clean out the tank?

    Thanks in advance for all of your help!

  2. #2
    Registered User d240zx2's Avatar
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    The most effective way would be to drop the tank and send it out for cleaning.

    You can continue to "dilute" the crud, but that will take a lot of time and a lot of gas and a lot of fuel filters.
    First & Third owner of HLS30-00721
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    Registered User mlc240z's Avatar
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    Agreed.
    If it's been sitting and you can see settling in the filter, it's probably in the lines: if it's in the lines, it's probably in the tank.
    You run the risk of sucking it up and clogging the lines even further or completely.

    Supposedly, a radiator shop will accept it and should be able to 'boil out' the gas tank for a reasonable amount of money.
    Bart

    5/71 240z, HLS30-31306, mostly stock, ZTherapy SU's, Pertronix, Eibach ProKit, KYB, Poly bushings, 60 amp alternator w/Dave's plug bypass, headlight and parking light harness upgrades.

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    Registered User dclamm's Avatar
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    I went through this on my recently purchased Z that sat for a long time. I dropped the tank and tried to drain the gunk, after a week upside down and spraying with various things it was obvious it wasn't all coming out. Paid $100 to have it cleaned at the radiator shop and lined with POR15 tank liner.

    I spent many hours trying to get the gunk out of the hard fuel lines. At first the line was completly clogged but I kept spraying carb cleaner from the engine side and blowing it through and it eventually came out clear. What a mess! It was in the carbs too, so I got a set of ZT carbs cause the stuff had stuck everything up.

    Good luck, hope you're not in as bad as shape I was.
    Dave
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    beandip beandip's Avatar
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    One of Our Club members was having problems with crud in the tank and Her husband cleaned and used POR-15. He told me that he had followed the instructions from POR and coated the tank. In abut 6 months the POR began flaking off and clogging the filter. He was able to find a newer 240 tank and how all is good. I had a conversation with Z Therapy owner. And the upshot is don't coat the tank! The stuff will come off and there is no way to completely clean the POR off once it is in there.
    Steve said that he has had to cut the tanks open and scrape them clean , weld the panel back on and he has them cad plated . for what its' worth this is the info I have. I have used POR on other stuff for years and am a true believer , but not inside a gas tank. I hope you have better luck. 240 tanks are becoming imposable to find.
    I'd rather die while I am living than live while I am dieing. CZC 1887 IZCC 12602 Member of NorthWest Z Car Club

  6. #6
    Registered User Jeff G 78's Avatar
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    I think POR-15 is as great as long as the instructions are followed EXACTLY. Cheat even the slightest bit and it will fail. I have done two Z tanks and both are doing fine so far. One was done a year ago and the other is going on four years. To do the job right, it takes about a week of back breaking labor. On both of my tanks, I had to add many pre-cleaning steps prior to even starting the POR process. I rinsed the tanks with water and lengths of chain at least 50 times first to get the majority of the rust out. After the water only rinse, I used water and muriatic acid to further prep the tanks for the actual POR treatment. I'm pretty sure I did a thread on it last fall. I'll look around and post the link to the thread when I find it.

    EDIT: I must not have posted pics. Here is my 260 tank before and after POR-15

    This is the inside of the tank after the Z sat in a barn for 15 years or so


    After a few water rinses, this is what I got out


    After a week of cleaning, here is the same tank inside ready for the sealer step


    Finally, after sealing
    Last edited by Jeff G 78; 06-30-2010 at 07:12 PM.
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    1972 240z Decoy12's Avatar
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    Thanks for all the replies guys! Sorry for the late response, I was being notified of all the responses by my email. Anyway I got another fuel filter, but at $6 its getting kind of expensive. I thought about diluting the crud, but it won't fix the problem in the long run. I am thinking also that running the car in such condition wouldn't be good for the carbs or the engine. I might as well take a look down there because I need to replace the filler hose thats leaky... Thanks for the replies and I will keep you guys updated.

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    I went through the same thing on a '70 that had sat for a long time. Ended up dropping the tank and cleaning it out. Now it seems to run out pretty well. I'll be sure to drain the tank next time I park it so it should start up easier next time.

    OK - thinking out loud here. I wonder if opening up the drain plug, draining the tank, then hitting the inside of the tank with a pressure washer would clean out a moderately dirty tank. That might be easier than dropping the tank - then again, it might just make a hell of a mess and then means dropping the tank while rolling around in a bunch of cruddy water. :-\

    NoCo Z club "Cruise, Wrench, Socialize"

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  9. #9
    1972 240z Decoy12's Avatar
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    Hey guys its been about 3 months now since I have been trying to solve this issue... I finally go the $$ to have the tank cleaned... After trying to clean it myself with many different solvents I had no real luck. I think the hard white stuff on the inside was calcium (according to the guy that cleaned it). Now I got some por-15 and coated the inside and it looks so much better now. I am about to attempt to place the tank in right now... wish me luck!

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    My 240 sat for 14 yrs when i bought it. I knew the tank had crud in it but wanted to get it out on the track before dropping the tank and replacing the vent hoses. I went through about 2 dozen fuel filters.

    After the track day I dropped it and took it to a car wash. The varnish that was in it came out in small sheets. The only spot I couldn't get to was behind the baffle. The inside of the tank still looked new. I still have a fuel filter before the stock electric pump as well as the one before the mechanical pump. I haven't had to change any of the filters for at least 5 yrs.

    Moral of the story, if you bought a car that has been sitting, one of the first things you need to do is drop the tank and clean it out.
    things will only bother you if you let them.

    82 280zxt 4 spd auto
    73 240z--lsd, cv axles
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  11. #11
    Marooned Fish cygnusx1's Avatar
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    My '72 sat for 23 years with gas in the tank. After draining out the molasses-like fuel. I dropped the tank and brought it to a tank shop. The crust was so bad that the shop did not want to mess with it. I found a better, cleaner tank, and then used a DIY tank cleaning and coating kit from KBS. http://www.kbs-coatings.com/ It worked well but you MUST follow every step exactly. Watch their videos. They are helpful.

    BTW The gunk is probably a varnish formed from old fuel.
    Last edited by cygnusx1; 10-16-2010 at 09:55 PM.
    Dave C, Putnam, NY
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    OH MAN DO I HAVE BAD NEWS Next to the fuel sending unit there are supposed to be hoses, one above the other. So everything was going well putting the tank back in... suddenly one of the metal "pipes" came clean off the tank! I am not sure what to do right now? Do I epoxy it in? Do I solder it in? I am not sure if I could solder it because I am not sure if the tank liner is flammable or not. I was so close to getting my Z back on the road Major Bummer!

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    Marooned Fish cygnusx1's Avatar
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    Did it break free because of rust or just a weld/solder separation? I am sure it can be repaired if the surrounding metal is clean.
    Dave C, Putnam, NY
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    Hey cygnusx1, It had actually come off the first time when I removed the tank because the hose was stuck to it. The guy that did the cleaning said that he would solder it before it got coated because he warned me that after its coated you couldnt apply heat to it. I work at a hardware store so ill pick up an epoxy or maybe a jb weld just in case. I'll call the guy to let him know that the piece he soldered came off lol

  15. #15
    Supporting Member EScanlon's Avatar
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    I would take it back to the guy that "soldered" it and have him repair it properly.

    I think he didn't solder it at all, that might explain why it "just came off". Properly soldered would have held.

    Don't use an epoxy paste. While JB Weld might work for a while, I don't know for how long it would CONTINUE to work. There are other epoxies out there which have been used and claim to be fuel-proof which might be spendier but better suited for this job. POR's Epoxy is one.

    However, I still think the guy you paid to do the job should be the one to take first crack at repairing it.

    2
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    Marooned Fish cygnusx1's Avatar
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    It might burn the coating around the fitting though. Not the end of the world.
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    Quote Originally Posted by EScanlon View Post

    I think he didn't solder it at all, that might explain why it "just came off".

    While JB Weld might work for a while, I don't know for how long it would CONTINUE to work.

    However, I still think the guy you paid to do the job should be the one to take first crack at repairing it.

    E
    Hey Escanlon, definitely true about him not doing it properly... it came off very "smoothly"... i can only describe it as "peeling" off lol. Anyway tomorrow I have a few hours before class so I will contact the guy about it. I will also find out if jb is gas proof or not, although I'm sure it won't be 100% since gas eats through alot...

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    Quote Originally Posted by cygnusx1 View Post
    It might burn the coating around the fitting though. Not the end of the world.
    Yea if it burns the coating I can always paint it over with some high heat enamel or some other spray paint I could get at work.

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    Ah......this thread brings back memories.









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    hey g9m3c thanks for sharing your pictures... looks like a lot of rust and build up there, it also looks like a lot of work! Looking back at Jeff's pictures as well as yours, my tank didnt look that bad on the half with the fuel level sender, but rather all the build up was on the far side.

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    You're welcome. I had my tank chemically cleaned at a local radiator shop and it looks MUCH better now.

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    Still plays with cars kenz240z's Avatar
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    I've cleaned a couple by removing the tank and cleaning with a pressure washer. Then a rinse with a bit of muriatic acid. Neither of the tanks I cleaned had any major rust or holes, so I simply re-installed back into the car. No problems with either one so far.

    As for the fitting, take a look at the auto parts store, they will likely have an epoxy for gas tank repair. While soldering would be an "authentic" fix, a cold weld with a fuel tank epoxy should do fine.
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    Thanks for the advice Kenny, I will look into that tomorrow since theres an autozone next to work. If not theres a kragen (o'reilly) and a napa by my house. I tried with the pressure washer twice but like i mentioned the build up was on the narrow side of the tank and since it has the single outlet it was hard to clean it. Then it got rusty lol but I had it cleaned by the radiator shop so its good now. Tried to get it in by myself today but didnt have much luck. I will try again tomorrow with a friend. Plus i need to buy bug spray I found black widows under my zed

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    The best insect and arachnid spray I have ever used is either 'carb cleaner' or 'electric motor cleaner' in a spray can. Its instantanious, always around the shop, no oily residue or strange smell. The flying insects, mostly wasps, will drop like rocks. I think it gums up their carbs.

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    Still plays with cars kenz240z's Avatar
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    Ditto on the carb cleaner, it does seem to "gum up the carbs" on wasps!

    Yeah, getting the tank back in by yourself can be a challenge. I've had good luck using a large floor jack with a block of wood under the tank to lift it up into position. The hardest part is getting the filler hose on to the filler neck of the tank. I little heat with a heat gun helps-easy does it with the heat-you don't want to melt it! If you don't have a heat gun, borrow your wife's hair dryer...
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    Quote Originally Posted by Bonzi Lon View Post
    The best insect and arachnid spray I have ever used is either 'carb cleaner'... in a spray can. Its instantanious, always around the shop, no oily residue or strange smell. The flying insects, mostly wasps, will drop like rocks. I think it gums up their carbs.

    Bonzi Lon
    Wow lol I never thought about using carb cleaner to kill things. You guys are great! How did you figure that out? Or is it common knowledge to everyone but me?

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    Quote Originally Posted by kenz240z View Post

    The hardest part is getting the filler hose on to the filler neck of the tank. I little heat with a heat gun helps-easy does it with the heat-you don't want to melt it! If you don't have a heat gun, borrow your wife's hair dryer...
    I actually go the filler hose back through the hole and reattached the tank to it. I was able to maneuver the tank with my arms and legs back into position (man did they leave no extra room down there). The jack is holding up the tank right now in postion but I will have to lower it again to reattach the hoses. I might have to lift the car some more too or put it on 4 jack stands because Its hard to access the front to attach the straps where I have it now. Any tips on the "order of operation"?

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    Default It is done!!

    Hello everyone... I guess y'all are busy or something. Anyway I finally got the tank inside. I had to replace one of the hoses because my 'friend' ripped it off and didnt tell me about and I couldn't see the end because of the braids. Now that I have it running I have encountered some electrical problems as well as a few mechanical ones. For one the headlights stopped working when I went to fill it with gas. Second the headlights came back on but the side lights and the tail lights didnt. The dashboard also didn't light the second time around. I'm thinking its a fuse problem so I will buy some fuses next door tomorrow after work. Next the timing is a little off and the throttle seems to be sticky. There must be an exhaust leak somewhere because I can smell it and it made me feel a little . Finally, I will buy another fuel filter and put it as I didn't have time today before the store closed. Thank you to all that guided me and gave me advice on how to handle my gas tank situation!

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