Sparkplug (spark plug) cross reference guide for Happy Time style engines

Discussion in 'Electrical' started by Fabian, May 21, 2010.

  1. Fabian

    Fabian Well-Known Member

    Sparkplug (spark plug) cross reference guide for NGK, Bosch, Denso & Champion

    Ok, been doing some research as to alternative plugs for the NGK BP*HS series that we seem to commonly use in our Happy Time or China Girl 2-stroke engines.

    Cross reference part numbers and equivalents.

    NGK BP5HS = Denso W16FP-U or Denso Iridium IWF 16 = Bosch W8B or W8BC or W8BP = Champion L92Y
    NGK BP6HS = Denso W20FP-U or Denso Iridium IWF 20 = Bosch W7B or W7BC or W7BP = Champion L87Y
    NGK BP7HS = Denso W22FP-U or Denso Iridium IWF 22 = Bosch W5B or W5BC or W5BP = Champion L64Y
    NGK BP8HS = Denso W24FP-U or Denso Iridium IWF 24 = Bosch = None......................= Champion L61Y

    Unfortunately, neither Denso or NGK manufacture a supplementary gap spark plug (multi pronged) to suit a 12.7mm thread reach.
    With NGK, each heat range figure gives 70 degrees celcius (158 degrees fahrenheit) temperature differential at the firing tip, to the next heat range above or below the nominated sparkplug.
    So, a BP7HS runs 70 degrees hotter than a BP8HS or 70 degrees cooler than a BP6HS sparkplug.

    Now you can go out and play till your hearts content.

    Last edited: May 21, 2010

  2. machiasmort

    machiasmort Active Member

    My unconfirmed notes, feedback appreciated....\

    Spark plug gap .22-.25
    NGK B6HS & B5HS
    Champion L86C
    Champion CJ7Y low profile ( I like these)
    Autolite 425
    ND W2OFS_U
    Bosch W9EO
    Diamond Fire E3.12
  3. Fabian

    Fabian Well-Known Member

    What was your impression of the Diamond Fire E3.12 spark plug.
    It's the closest thing available to a supplementary gap (multi pronged) spark plug, which is my preferred option.

    Have you tried the projector nose equivalent of the NGK B*HS series, being the BP*HS

  4. machiasmort

    machiasmort Active Member

    I have not tried any of them yet, these were notes that I took from other sources on the web...
  5. GearNut

    GearNut Active Member

    I put an E3.10 in my HT engine. It starts easier and runs wonderfully.
    I have not put many miles on it though, as the dilapidated bicycle is not up to the task.
    I cannot give you long term results.
  6. srdavo

    srdavo Active Member

  7. Delaware Destroyer

    Delaware Destroyer New Member

    After breaking the stock plug trying to remove it.I went with the Champion L86c plug. It has been in there several hundred mile no problems, quick starts. Napa also also crossed a Autolite plug 425. will try it next...I also use AMSOIL Interceptor oil a synthetic blend 10 oz to 2 gal... Very smooth running motor..
  8. machiasmort

    machiasmort Active Member

    Dave, I'm sorry, I forgot? Probably other chat blogs. I opened up microsoft word and started dumping other peoples notes (copy,cut,paste) to it.

    I've assembled a serious collection of info on our 2strks, have it in word format but can't post it here due to size constaint of the board. PM me your regular e-mail adress if as a MOD, you can post it! Would be of value to others!
  9. srdavo

    srdavo Active Member

    yes...I'd like to see your info.

    PM sent
  10. adb140275

    adb140275 Member

    b5hs is an autolite 2656 if memory serves me correctly... I'm not sure why everyone leaves autolites out
  11. justinsidethegates

    justinsidethegates New Member

    I was wondering in your opinion what heat range should be run in a given ambient temperature. I read somewhere to use the NGK BP5HS when the outside temp is below 70F and the NGK BP6HS from 70F to 110F. I found the ACDelco R44F which should be the equivalent to the BP5HS(according to CarQuest) and tried it out in temps under 70F and it ran ok but best at temps below 60F. The NGK B6HS tends to run well at all temps even warmer temps up to 96F this week in SoCal but always feels less powerful than the hotter range ACDELCO R44F. Maybe just between nice cold air in the cylinder and a nice hot plug its the best combo... And its hard to compare across different manufacturers so i was wondering if anyone else has figured this out.
    Also tried a plug a local mechanic with a MB recommended that he found at a local mower shop. Oregon 77-301-1 plug is much shorter than the others but is the same length into the cylinder. The cross references on the box are to NGK B2LM Champion J19LM and the Bosch W9E0. He swears by this plug even after trying loaning him my B6HS to try out.
    For now my NGK B6HS is staying in til i can figure out the best iridium plug to go with and probably shell out the $7-$8 for one rather than the $2.50 i've spent each of the ones i've bought so far. So if you know the best one that iridium plug out there let me know.
  12. happycheapskate

    happycheapskate Active Member

    Champion J19LM is a very common lawnmower spark plug. I am using it now. Seems to work fine. Starts easy. I used Champion EZ Start plug before too.

    Video from NGK describes the "heat range" of spark plugs
  13. happycheapskate

    happycheapskate Active Member

    Make your own spark plug testor, $3 (yes three dollars)

    Basically it holds and grounds the plug while you "start" the motor and see with your own engine and ignition system what the spark looks like, or if plug is dead. Be cautious, as obviously an open spark can ignite fuel vapors!
    Last edited: Jul 9, 2011
  14. HeadSmess

    HeadSmess Well-Known Member

    3 dollars is a lot of money... :jester:
  15. happycheapskate

    happycheapskate Active Member

    Some of the battery powered go-kart tuning plug testors are $150.