Hey gang, CNGchat needs your help!

For over a decade we have enjoyed providing this little corner of the Internet for folks to discuss all things natural gas vehicles. It is the largest forum of its kind: with some 70,000 posts on over 11,000 topics. But with continued low gasoline & diesel prices and strong automaker support for electric vehicles, consumer interest in CNG has dropped considerably, and with it has visitor traffic here. As a result, Google ad revenues no longer cover hosting fees.

If you find CNGchat to be a useful resource then please consider making a modest donation to support keeping this remarkable pool of knowledge available to the alternative fuels community. Thanks!

See more
See less

Is this tank safe?

  • Filter
  • Time
  • Show
Clear All
new posts

  • Is this tank safe?

    Apparently this tank has been sitting on a shelf for 2 years. 11/12 man. Date. But it has this scuff mark! Any opinions?

  • #2
    The rule of thumb is, if you can hook fingernail on a defect it is a failure. If there is a question have a certified inspector look the tank.


    • #3
      ThatitGuy, I'll weigh in on this one. This is a Lincoln Type 4 composite. Mike is right about the fingernail scratch, but this only applies to the side wall. This is on the dome where the tolerances are generally more lenient. Between 0.011 and 0,035 deep scratches can be repaired with a two part epoxy. Greater than 0,036, Lincoln should be consulted. You've still got 20 yrs left on this cylinder. It's worth the effort to resolve it. Good luck, afvman/Bill


      • #4
        As much as I want this, and know it will almost certainly be just fine I can't do it. Since I don't know the history of this one I'm passing on it. It was most likely dropped. Talked to the field safety inspector at Lincoln and he said to pass on this. He recommended talking to a company called digital wave out of Denver that does acustic testing on tanks. Their tech said its might be level 3 damage and tank should most likely be discarded. Found a great manual on tank damage I'll post below. Found this thing on ebay and the seller said there was absolutely no scratches or damage to it. I insisted on lots more pics from all angles and he came clean with these pics. After I passed and told him why, he just put it back on ebay sans the damage photos.


        • #5
          Cylinder manual
          Attached Files


          • #6
            Hi I purchased the above referenced tank, drove to Chicago to inspect it first hand, what appears to be a scuff in pictures is actually a polished spot in person, no scratch no exposed fibers no cracked resin, I assume where the cover rubbed on the tank. I hooked up a gauge and battery and activated valve, tank had been stored on shelf for two years with 2800 psi on it!!!! rest of tank was mint. Bought for less than the cost of the valve and brought home .


            • #7
              to make any kind of accurate appraisal of one of these tanks you really have to look it over first hand in person or pay someone with the knowledge to do it for you. I have bought three Lincoln type 4 in the last 18 months two complete set ups, 21x60 out of late model factory Chevrolets and this one all tanks in mint condition with electric valves for less than 1,000 dollars total investment not counting my time to go remove them. currently with gasoline dirt cheap these can be picked up for a little bit of nothing and makes an entirely different economic assumption out of running cng.