Page 2 of 3 FirstFirst 123 LastLast
Results 11 to 20 of 25
  1. #11
    Join Date
    Feb 2007
    Location
    Billericay, Essex, England.
    Posts
    908
    You've all got me worried now...

    My Dax hasn't had an earth on the fuel tank for 22 years - should I be worried??

    Or, is the earth that is connected to the sender enough?

    No earth on the filler either.

    Sean
    Too many idiots, not enough villages!

  2. #12
    Join Date
    Feb 2020
    Location
    Surrey
    Posts
    20
    It's just good practice to link all the large lumps of metal together to get them all to the same potential and makes life much easier/safer. As the bodyshell may be non conducting, the chassis is the main earth return path for everything, so you need a really secure strap to a bare point on the chassis from anything that has rubber mountings such as the engine, gearbox, fuel tank and radiator - then you can get the lights and all the other small parts connected to the chassis - finding a earth fault is one of the hardest jobs to do if a light starts to flicker. In the case of the fuel filler it is just possible that it could be at a different potential to the filler nozzle (rubber hose to the tank presumably) and this is the last place you need static electricity to build up, so add a length of black wire - it costs nothing.

    On an old Mini I had the embarrassment of losing power and the fault was eventually traced to the throttle return spring. The engine earth had corroded at the chassis and was failing, and the only way for the engine to securely connect to the chassis was through the spring which was fixed between the carb and the chassis - the spring got red hot.

  3. #13
    Join Date
    Jul 2012
    Location
    NW England
    Posts
    682
    Quote Originally Posted by Rudolph View Post
    On an old Mini I had the embarrassment of losing power and the fault was eventually traced to the throttle return spring. The engine earth had corroded at the chassis and was failing, and the only way for the engine to securely connect to the chassis was through the spring which was fixed between the carb and the chassis - the spring got red hot.
    I remember a workmate telling me similar story many years ago but it was the handbrake cable which provided the “line of least resistance” which promptly melted and caused it to fail.
    if I recall correctly that was a mini too.

    Must admit, although I have always supplied a wire link from my tank to the filler I often wondered how this is supposed to work as the car itself is not “earthed”. I remember years ago you used to see a few cars with a bit of chain hanging from the exhaust which was supposed to be for this reason.
    Last edited by GDCobra; 03-05-21 at 07:43 PM.

  4. #14
    Join Date
    Feb 2007
    Location
    West Sussex
    Posts
    9,421
    Quote Originally Posted by Cobragreyhead View Post
    Are they not earthed through the mounting bolts to chassis?
    You're right. But its good engineering practice to have a dedicated electrical connection as well, as rust/other crap etc 'might' cause an issue.

    IIRC I argued that my tank was earthed via the fuel level sender, as I could show an earth wire from it going to the chassis.
    On the filler cap (and yes I was asked about this), I added an earth tag to the underside of one of the filler neck flange mounting bolts, ran this down the filler tube in the boot, clipped using zip ties and then earthed it onto the tail light loom cluster. I opened the boot and they could look in with a torch to check all OK.

    Aaron: they were happy to look at where ever I directed them for the requisite IVA reg. Although I had lots of pics standing by, especially for the triangulation I had to do on the seatbelts, the only time I needed photos was for the engine number which was virtually impossible to see with the naked eye. Took me ages to get an acceptable legible pic of this before the test - had to show that this was indeed the same engine, through evidence of paint chip and identical ancillary items in the photo as well as demonstrable on the car.
    Last edited by KevinW; 03-05-21 at 09:00 PM.
    Crendon Chassis No.49
    Huddart FE428 + toploader

    Not listed in the Shelby Register.

  5. #15
    Join Date
    May 2020
    Location
    west sussex
    Posts
    47
    Quote Originally Posted by Rudolph View Post
    It's just good practice to link all the large lumps of metal together to get them all to the same potential and makes life much easier/safer. As the bodyshell may be non conducting, the chassis is the main earth return path for everything, so you need a really secure strap to a bare point on the chassis from anything that has rubber mountings such as the engine, gearbox, fuel tank and radiator - then you can get the lights and all the other small parts connected to the chassis - finding a earth fault is one of the hardest jobs to do if a light starts to flicker. In the case of the fuel filler it is just possible that it could be at a different potential to the filler nozzle (rubber hose to the tank presumably) and this is the last place you need static electricity to build up, so add a length of black wire - it costs nothing.

    On an old Mini I had the embarrassment of losing power and the fault was eventually traced to the throttle return spring. The engine earth had corroded at the chassis and was failing, and the only way for the engine to securely connect to the chassis was through the spring which was fixed between the carb and the chassis - the spring got red hot.
    I'm a panel beater by trade, classic minis were very popular in my teens/early twenties, the poor earth was a common problem and usually resulted in earthing through the manual choke cable

  6. #16
    Join Date
    May 2020
    Location
    west sussex
    Posts
    47
    Quote Originally Posted by KevinW View Post
    You're right. But its good engineering practice to have a dedicated electrical connection as well, as rust/other crap etc 'might' cause an issue.

    IIRC I argued that my tank was earthed via the fuel level sender, as I could show an earth wire from it going to the chassis.
    On the filler cap (and yes I was asked about this), I added an earth tag to the underside of one of the filler neck flange mounting bolts, ran this down the filler tube in the boot, clipped using zip ties and then earthed it onto the tail light loom cluster. I opened the boot and they could look in with a torch to check all OK.

    Aaron: they were happy to look at where ever I directed them for the requisite IVA reg. Although I had lots of pics standing by, especially for the triangulation I had to do on the seatbelts, the only time I needed photos was for the engine number which was virtually impossible to see with the naked eye. Took me ages to get an acceptable legible pic of this before the test - had to show that this was indeed the same engine, through evidence of paint chip and identical ancillary items in the photo as well as demonstrable on the car.
    Not really sure how the filler cap can be earthed on mine?

    It pushes through the rubber seal and into the short rubber hose connected to tank, so no bolts to get connection for earth from and neck of filler is completely inserted into hose.

    I could drill hole through side of filler neck and tap it out, then cut rubber hose to allow earth screw fixing... but surprised this is really necessary.

    Other simple option might be simply to insert bare wire inside hose where the jubilee clip clamps it... but would that be acceptable?

  7. #17
    Join Date
    Feb 2007
    Location
    West Sussex
    Posts
    9,421
    Quote Originally Posted by TurboFreak View Post
    Not really sure how the filler cap can be earthed on mine?

    It pushes through the rubber seal and into the short rubber hose connected to tank, so no bolts to get connection for earth from and neck of filler is completely inserted into hose.

    I could drill hole through side of filler neck and tap it out, then cut rubber hose to allow earth screw fixing... but surprised this is really necessary.

    Other simple option might be simply to insert bare wire inside hose where the jubilee clip clamps it... but would that be acceptable?
    You're right, the petrol cap is usually fully insulated from the tank because of the rubber pipe connection, and the fact that we have grp bodies.
    Are you saying there are no screws on the flange/neck that bolts to the body? - that's what I used. Never seen one that didn't have some mounting screws or bolts of some sort om the flange part.
    if not, then I guess you could use braided earth cable round the jubilee clip.
    Crendon Chassis No.49
    Huddart FE428 + toploader

    Not listed in the Shelby Register.

  8. #18
    Join Date
    May 2016
    Location
    Hockley ,Essex
    Age
    58
    Posts
    373
    Quote Originally Posted by GUMBALL View Post
    You've all got me worried now...

    My Dax hasn't had an earth on the fuel tank for 22 years - should I be worried??

    Or, is the earth that is connected to the sender enough?

    No earth on the filler either.

    Sean
    I wouldn't get too worried about it, but if you are, it doesn't take much effort
    to sort it.
    I've just done mine on my SR cobra, you don't need heavy gauge wire to carry
    out the work as there is no high current involved with static electricity.
    What I would add, as you have mentioned the fuel sender unit earthing,
    mine is insulated earth return so would have no effect on the metal fuel tank earth .
    As a guess I would think most are insulated earth return and not the normal standard
    earth return units.
    I have had my cob for over twenty years as well, so this thread has prompted me to
    do it !
    Thanks to all those who have bought this to my attention.
    Chris.

  9. #19
    Join Date
    May 2016
    Location
    Hockley ,Essex
    Age
    58
    Posts
    373
    Just to add ,
    mine was built pre sva

  10. #20
    Join Date
    May 2016
    Location
    Hockley ,Essex
    Age
    58
    Posts
    373
    Quote Originally Posted by Cobragreyhead View Post
    Are they not earthed through the mounting bolts to chassis?
    I'm sure the early DAX was similar to my SR and therefore the tank strap bolts do not earth through
    the chassis.
    Chris.

Page 2 of 3 FirstFirst 123 LastLast

Tags for this Thread

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •