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Cleaning spark plugs with ammonia.

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  • Ignition: Cleaning spark plugs with ammonia.

    Used to hear about cleaning old spark plugs with household ammonia, but never tried it. yesterday, I did. Verdict: it works very well. I took a whole mess of H14Y's and a few J8's, and put them in an old stainless steel saucepan, and covered them with ammonia from the local grocery store. Took almost 2 liters, set the pan outside (because, fumes) and let it soak a little over 24 hours. This afternoon, I took an old toothbrush, and scrubbed the gunk off them as much as I could, and blew out the business end of the plugs with compressed air.

    The exterior insulators, shells, and threads cleaned up as well as one could want; 100% degreased, and the white insulators sparkled, except for one small group of H14Y's which had little freckles in the grooves of the insulator. Possibly plugs from one engine that got exposed to something caustic? Didn't take rust off the shells, nor did I expect it to.

    On the business end, maybe a third of them were completely stripped of gunk, as deep in as I could see, and could be put in service as-is. Of the remainder, in most cases, the hard deposits were somewhat softened, but not all removed. They should clean up readily with the abrasive blaster, and in a lot less time than if I were to try to blast them with the deposits oil-soaked.

    I don't think soaking over 48 hours would be helpful, as the ammonia had lost most of its strength in the first 24. The toothbrush work took about an hour and a half, and I scrubbed 88 plugs in that time, so roughly a minute each. I doubt I will spend more than a few seconds on each one, when it comes time to clean them in the abrasive blaster.

    One curious discovery: H14Y plugs evidently changed at least once. The older (?) ones have a plain-sided steel shell, with a short external insulator, and a more extended tip; compared to the newer (?) ones that have broad groove in the steel shell. The tip doesn't protrude as far into the cylinder, and the outer insulator is about "one ridge" taller.
    Gord Richmond, within Weasel range of the Alberta Badlands

  • #2
    Thanks for the tip, Gordon.
    I might try it now. I thought that this could damage the protective coating of the thread, but if it was the case, you'd have noticed it.
    As for Champion spark plugs, they were my choice for years but I don't use them so often now . My Hawk prefers NGK B4L. Like Standard products, the Champion quality took a serious dive.
    By the way, about the rear glass, I forwarded your address to the friend. I hope he'll keep in touch with you. Besides, StudeRich noticed that local auto glass shops are able to make a suitable package for it. This might be simpler for you.
    Nice day to all.


    • #3
      I to have noticed a difference in the H14Y plugs as you describe. cut backs i guess. my plugs get enough running to burn away most deposits though they will get sooty now and again. a brass brush and a bit of emery cloth do the trick in my case.Thanx for tip Luck Doofus


      • #4
        "Cleaning" only a tiny percentage of how a spark plug works.

        Both the ground and the center electrode "need" to have sharp edges to not overload the rest of the ignition system. Spark "likes" to jump sharp edges, not round surfaces.

        So, get out your small fine files boys, keep the surfaces parallel.