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Thread: Spark plugs

  1. #11
    Senior Member efwd's Avatar
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    Default Re: Spark plugs

    Anybody using an alternative spark plug to the
    ROTAX SPARK PLUG 297-656 used on the 912iS which cost $21 each?
    Eddie Forward
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    SS7, 912iS, Garmin G3X

  2. #12
    Super Moderator Av8r3400's Avatar
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    Default Re: Spark plugs

    I'm still using the same NGK DCPR8E plugs (gapped to .020") I have always used in my engine. No plans to change to the "Rotax" brand plugs.

    I have the same opinion on continuing to use Mobil-1 Racing 4T.
    Av8r3400
    Kitfox Model IV
    The Mangy Fox
    912UL 105hp Zipper
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  3. #13
    Senior Member efwd's Avatar
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    Default Re: Spark plugs

    Thanks Larry. I happened to note that those NGK plugs are what is in the Rotax Parts list of Old. Not that old but they have since started putting their name on the side of what is likely the same plug. I have just ordered my new NGK plugs from AS&S.
    Eddie Forward
    Building
    SS7, 912iS, Garmin G3X

  4. #14

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    Default Re: Spark plugs

    Quote Originally Posted by Flybyjim View Post
    Hi Mic,

    Yes, I am always amused when I see folks trying to save a couple $$ on spark plugs and Rotax oil filters when they spend more than $40,000 for a plane. We only get one ride in this rodeo, better have a good saddle and a sound plan.

    How was the harvest?

    Jim
    I used to work on corporate jets, The annual/Phase 4 inspections were about 150,000 or more. we had owners not blink at $150,000 for an inspection then argue the price on a $20 part.

  5. #15
    Senior Member efwd's Avatar
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    Default Re: Spark plugs

    Yeah, I would like to have their bank account as a result too. That is likely why they have $150K available to do the work in the first place. When NGK plugs were the prescribed plug and all was good, why would I need to pay 5X the price because it is labeled differently? Rotax is obviously not differentiating between what they sell for their certified engine and what is fine in their experimental engine. I don't need to pay certified prices for my engine as it is not certified. No problem here spending money when it is warranted.
    Eddie Forward
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    SS7, 912iS, Garmin G3X

  6. #16
    Senior Member jiott's Avatar
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    Default Re: Spark plugs

    Eddie, there are many, many of us staying with the tried and true NGK plugs.
    Jim Ott
    Portland, OR
    Kitfox SS7 flying
    Rotax 912ULS

  7. #17
    Senior Member jiott's Avatar
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    Default Re: Spark plugs

    In fact, I would argue that the new Rotax plugs are LESS proven and have the possibility of problems yet to show up, compared to the NGK plugs track record of reliability for umpty-ump years. I could be wrong, but I don't believe the Rotax plugs are just rebranded NGK plugs.
    Jim Ott
    Portland, OR
    Kitfox SS7 flying
    Rotax 912ULS

  8. #18
    Senior Member Dave S's Avatar
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    Default Re: Spark plugs

    FWIW - According to a detailed look at Rotax documentation on this deal, The new plugs are designed to go with the new boots; however, Rotax also says that the NGK branded plugs are fine to use, till they are no longer available (from Rotax).

    The NGK plugs can be found from many vendors dealing with motorsports like quads, snow machines, motorcycles, etc; and, they vary in cost from $2.52 to almost $5 depending on who you buy them from.

    I am sure it is not possible to determine to what extent the actual engineering is different with the new boots and plugs other than the shape of the boots and the name on the plug. That information is internal company info that will not be shared, I am sure.

    My suspicion is this probably has more to do with dueling lawyer over the aviation use of NGK products than anything else. No idea who makes the new Rotax plugs, however, it is not beyond possibilities that NGK could make them but brands them for Rotax. The branding basically moves some of the product liability to the entity who's name is on product from the manufacturer.

    On a sidebar comment about plugs - no matter new or used or whatever brand, I have always checked the resistance of the center conductor ( should be 5K ohms on these) and ocasionally find a plug, not necessarily used, which doesn't meet spec. A high resistance plug will still fire; but, who knows when/if it will fail. New plugs are not necessarily without flaws.

    Certainly a person is generally OK with Rotax branded parts (although they have had a few bad parts of their own in the past), I see no reason to switch to the Rotax branded plugs on our 912ULS.

    Jim's comment about the reliability of the NGK branded plugs rings true.
    Dave S
    Kitfox 7 Trigear (Flying since 2009)
    912ULS Warp Drive

    St Paul, MN

  9. #19
    Administrator DesertFox4's Avatar
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    Default Re: Spark plugs

    Dave S- no matter new or used or whatever brand, I have always checked the resistance of the center conductor ( should be 5K ohms on these)
    Thanks Dave for this. 👍. Will be checking every new spark plug in the future. Added it to my iPAD notes on regular Rotax 912 ULS maintenance.


    DesertFox4
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  10. #20
    Senior Member efwd's Avatar
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    Default Re: Spark plugs

    Okay, a follow on to the issues. I pulled my plugs and found them to be the NGK plugs. This engine was delivered from the factory with these plugs. I first bought replacements at Aircraft Spruce and found them to be the incorrect model of the correct part. Only one model has the metal top that will unscrew and leave you with the threaded post that is required. It is my understanding that NGK chose to not accept the liability for aviation use so now they have a big red X over an airplane and a trike right on the box. Problem with this was they were still manufacturing plugs for an aircraft engine manufacturer so... they quit Rotax. So, either they have actually quit, or they manufacture the plug ( or someone else does ) and label it as a Rotax manufactured part and up the price 10 fold to cover the liability.
    Eddie Forward
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    SS7, 912iS, Garmin G3X

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