Results 1 to 17 of 17

Thread: Recovering fouled spark plugs.

  1. #1
    Baja-Forum Maniac brer rabbit's Avatar
    Join Date
    Jun 2010
    Location
    Somewhere between Liverpool & Chester.
    Posts
    1,155

    Default Recovering fouled spark plugs.

    How often have you heard the advice "if the plug doesn't spark then toss it away and thrown in a new one"?

    I've been using the same two CMR6H & 7H plugs for the last 3 years thanks to this method.

    So I'll show you a way to recover some of your old plugs, save yourself a bit of money and add a few more plugs back into your pool of field spares.

    This 'guide' is for carbon & oil fouled plugs, NOT cooked to death lean fried plugs with a melted electrode and cracked porcelain. You can also do this to generally clean plugs up before your weekend race or bash. We will be using some chemicals so you'd be advised to use some protective equipment for your eyes and hands and be ready to soak under some cold running water if you have a booboo...

    You will need:
    - carbon or oil fouled plug;
    - bottle of cream cleaner;
    - bottle of Harpic power Plus;
    - old tooth brush (preferably one you no longer use for your teeth)...
    - can of WD40
    - kitchen roll or clean rag
    - pair of gloves or barrier cream
    - eye protection.

    Okay so take your typical carbon/oil fouled plug. Salvaged this from mates tool box 6 months ago after carbon fouling caused it to short out:



    Apply some:


    And scrub the electrode & insulator with a bit of vigor using your old toothbrush. Your doing this to remove any loose build up, oil/grease. If you skip this then the oil coating the plug will prevent the next stage from working.

    Thoroughly rinse the plug out with water and you should have something looking like this:



    At this stage the plug would likely work, but we're going to get it nice and clean so we get more then a few sessions out of it.

    Next you need to apply 2 small drops Harpic around the insulator and electrode.



    Shortly after it may start to bubble and froth, this is good - the Harpic is reacting with the carbon build up and breaking it down (same as it breaks down calcium deposits in your crapper).



    Leave it for 5 mins, go make yourself a cup of tea, after which it should have settled down and look a little like this:



    Give it another scrub down with your tooth brush under a running tap. If there is a lot of build up it might benefit from a little light probing with a tooth pick or pin around the electrode and inner edge of the steel jacket & ring - the carbon should be fairly soft and easily dislodged, after which you can give it another round of Jif and Harpic as you did earlier - the most fouled plugs generally only need 2 rounds to get them close to new.

    Happy that the oil and carbon are gone? then scrub down with some washing up liquid and rinse thoroughly again, you don't want any Harpic or Jif getting into your engine, scrub all the threads and under the washer also.

    When your done you should be left with something like this:



    Happy with the result, then spray with a little WD40 to get rid of any water and dry off on some rag.

    Fit in your plug boot, touch the steel plug case to your exhaust and pull you pullstart to check it sparks, Job done.

    Now go have some fun, spend your newly saved money on some drink, fags or whatever you creatures enjoy doing...
    Last edited by brer rabbit; 15-03-2011 at 22:17.

  2. #2
    Senior Member Baja Duner SS's Avatar
    Join Date
    Apr 2010
    Location
    Indiana, USA
    Posts
    508

    Default

    What a great tip. Nice write up. I think I'll try that sometime.

  3. #3
    Baja-Forum Maniac brer rabbit's Avatar
    Join Date
    Jun 2010
    Location
    Somewhere between Liverpool & Chester.
    Posts
    1,155

    Default

    Quote Originally Posted by Baja Duner SS View Post
    What a great tip. Nice write up. I think I'll try that sometime.
    Don't know what the American equivilant to Harpic is but here's whats in it:

    100g of liquid contains 10.5g hydrochloric acid. <5% non-ionic surfactants, <5% cationic sufactants, Disinfectant, Perfume.

    But look around at the limescale removing toilet bowl cleaners...



    ...also works good in kettles.

  4. #4
    Now then, It's TOPPER! Topper's Avatar
    Join Date
    Oct 2009
    Location
    South
    Posts
    11,573

    Default

    Another great guide, I'll slap some sticky stuff on this before it disappears into cyberspace

    Maybe the engine section would be more appropriate ?

  5. #5
    Baja-Forum Maniac brer rabbit's Avatar
    Join Date
    Jun 2010
    Location
    Somewhere between Liverpool & Chester.
    Posts
    1,155

    Default

    Geez don't do that...



    ...Who looks at the stickies?...


    j/k.


    ya wherever you thinks good.

  6. #6
    Baja-Forum Maniac Neon-RC's Avatar
    Join Date
    Feb 2010
    Location
    Rainford, St Helens
    Posts
    1,135

    Default

    nice guide! one of my 7r's are pretty heavilly carbon coated so might try this
    and idea if the bleach trick will work with Nitro Glow plugs?
    Built to bash, Rebuilt to perfection

  7. #7
    Baja-Forum Maniac brer rabbit's Avatar
    Join Date
    Jun 2010
    Location
    Somewhere between Liverpool & Chester.
    Posts
    1,155

    Default

    Nah, tried bleach didn't work has to be Harpic power plus.

    Neither did caustic soda or sink unblocker...

    Worth a try on the glow plugs but that platinum coil looks very delicate.

  8. #8
    Baja-Forum Maniac Neon-RC's Avatar
    Join Date
    Feb 2010
    Location
    Rainford, St Helens
    Posts
    1,135

    Default

    just dont brush it?
    Built to bash, Rebuilt to perfection

  9. #9
    Baja-Forum Maniac brer rabbit's Avatar
    Join Date
    Jun 2010
    Location
    Somewhere between Liverpool & Chester.
    Posts
    1,155

    Default

    Who knows, give it a go then post it on some nitro forums as your own idea lol.

  10. #10
    Baja-Forum Maniac Neon-RC's Avatar
    Join Date
    Feb 2010
    Location
    Rainford, St Helens
    Posts
    1,135

    Default

    havnt got any harpic lol
    Built to bash, Rebuilt to perfection

  11. #11
    Baja-Forum Maniac brer rabbit's Avatar
    Join Date
    Jun 2010
    Location
    Somewhere between Liverpool & Chester.
    Posts
    1,155

    Default

    ASDA - 2 for 2

    1 for your spark plugs, the other to get the yellow stained limescale off your toilet.

  12. #12
    Member towie's Avatar
    Join Date
    Jun 2011
    Location
    hexham
    Posts
    287

    Post

    Thats a brilliant tip bud ! But can i suggest instead of WD40 you use ptfe spray ? does exactly the same jobs but repels dust , grit etc, where as 40 attracts it ? . I have used it for a long time and its good stuff,. can use it on ball joints, suspension pins etc etc etc ... Its even good for cleaning as it leaves no sticky residue and leabve s all bits nice and shiny !!!

    cheers.

  13. #13
    Baja-Forum Maniac voo2doo's Avatar
    Join Date
    Mar 2010
    Location
    North Wales
    Posts
    2,489

    Default

    Or use a wire brush....

    J.
    .............................................BAJA OBLITERATOR!...................................... ....................

  14. #14
    Member bristolbaja's Avatar
    Join Date
    Apr 2012
    Location
    lawrence weston,bristol
    Posts
    265

    Default

    nice reconditioning tip
    time to get my old plugs out the scrap bin

  15. #15
    Senior Member
    Join Date
    Apr 2010
    Location
    durham
    Posts
    591

    Default

    lucky for me don,t have to bother as i have to a bead blaster in my garage takes about 30 secs to clean a plug to as good as new have not had to buy a new plug in two years LOL..

  16. #16
    Junior Member
    Join Date
    May 2012
    Location
    Slovenija
    Posts
    87

    Default

    clean easy cleaning

  17. #17
    Member
    Join Date
    Jun 2012
    Location
    london
    Posts
    59

    Default

    i have to say thanks a bunch for this tut man, since i saw this ive now revived 5 ngk iridium plugs, would of never thought to use this combo of products.

    top wright up.

Posting Permissions

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