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History Leonard high compression spark plugs?

Discussion in 'The Hokey Ass Message Board' started by theHIGHLANDER, Feb 17, 2019.

  1. theHIGHLANDER
    Joined: Jun 3, 2005
    Posts: 7,554

    theHIGHLANDER
    Member

    So I have something only the detail freaks would notice or appreciate. A set of 8 Leonard 14 F "High Compression" spark plugs. They're all side gapped, which according to an image search is how they were made. They're 14mm and will fit my flatty once I clean the threads. Frankly I can't remember what I took them out of but they were too kool to toss away and actually fire despite the existing crud. I'm well aware of the 'useless w/out pics' rule so I'll take some later or tomorrow and add them here. I also did some searching for history and all I found was that they're in the Smithsonian in some way and listed/cataloged, but no story. When all else fails the best source is, you guessed it, right here. I'll take all the info that's fit to print. I promise, pics soon. No really, I will.

    Quick edit: the Smithsonian has their catalog on file in the the library. Didn't see anything about actual plugs.
     
    Last edited: Feb 17, 2019
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  2. The37Kid
    Joined: Apr 30, 2004
    Posts: 24,904

    The37Kid
    Member

    Photos, that's The Point.

    Bob DSCF0004.JPG
     
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  3. ROADSTER1927
    Joined: Feb 14, 2009
    Posts: 2,423

    ROADSTER1927
    Member

    Still Waiting-----LOL Gary:D leonard.jpg leonard b.jpg
     
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  4. blowby
    Joined: Dec 27, 2012
    Posts: 5,484

    blowby
    Member
    from Nicasio Ca

    Ah I get it, I think. The side gap clears the block/valves/pistons on high compression engines? I had to shim up the plugs in my 60 to keep from closing the gap.
     
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  5. slowmotion
    Joined: Nov 21, 2011
    Posts: 2,948

    slowmotion
    Member

    No indexing required to boot. Cool!
     
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  6. Deuces
    Joined: Nov 3, 2009
    Posts: 15,943

    Deuces
    Member
    from Michigan

    That's worth about 5 ponies or better.... ;)
     
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  7. tubman
    Joined: May 16, 2007
    Posts: 3,860

    tubman
    Member

    When I was a kid, we heard about "hi-compression hubcaps", but this a new one on me!
     
  8. blowby
    Joined: Dec 27, 2012
    Posts: 5,484

    blowby
    Member
    from Nicasio Ca

    Anyone interested in some high lift connecting rods?
     
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  9. ROADSTER1927
    Joined: Feb 14, 2009
    Posts: 2,423

    ROADSTER1927
    Member

    OK, when does Soon expire? LOL Gary:D
     
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  10. theHIGHLANDER
    Joined: Jun 3, 2005
    Posts: 7,554

    theHIGHLANDER
    Member

    I might A-B-A test these plugs and see if they actually make a difference. Yes or no, I think they're kool. Found some old boxes online and they refer to the holes under the wire end as "air cooled". Kooky...
    20190218_165438.jpg 20190218_165814.jpg 20190218_165959.jpg 20190218_165646.jpg 20190218_165753.jpg
     
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  11. theHIGHLANDER
    Joined: Jun 3, 2005
    Posts: 7,554

    theHIGHLANDER
    Member

    So nobody knows anything about these?
     
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  12. Deuces
    Joined: Nov 3, 2009
    Posts: 15,943

    Deuces
    Member
    from Michigan

    I wouldn't mind trying one out on my Briggs and Stratton powered lawn mower.... ;)
     
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  13. ROADSTER1927
    Joined: Feb 14, 2009
    Posts: 2,423

    ROADSTER1927
    Member

    Sorry I just have the one plug in my collection and it fits my Harley single. Gary
     
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  14. I've heard of High Altitude flat heads, but not High Compression spark plugs.
     
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  15. theHIGHLANDER
    Joined: Jun 3, 2005
    Posts: 7,554

    theHIGHLANDER
    Member

    Just so it's clear, I dont expect to set an El Mirage record with spark plugs. I thought they're kool, I'm a fan of side gaps, and to see one done that way from way back when is intriguing to say the least. I guess their history will remain fleeting and mysterious. I'ma run em anyways even if it doesn't make a diff. Should be a nice mate to the Holthouse coil.

    Lawn mowers, WTF...:eek:
     
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  16. Deuces
    Joined: Nov 3, 2009
    Posts: 15,943

    Deuces
    Member
    from Michigan

    Just kidding..... :D:oops:
     
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  17. Bigchuck
    Joined: Oct 23, 2007
    Posts: 1,110

    Bigchuck
    Member
    from Austin, TX

    I know they look like they would make good fishin' weights!
     
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  18. oldolds
    Joined: Oct 18, 2010
    Posts: 2,620

    oldolds
    Member

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