Spark Plug To Compression Testing Nipple

Discussion in 'Workshop Tips and Secrets / Tools' started by Vision_2012, Apr 25, 2016.

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  1. Apr 25, 2016 #1

    Vision_2012

    Vision_2012

    Vision_2012

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    Hi,
    I want to convert a spark plug to accept a quick disconnect nipple to do leak down compression testing.

    I found it very hard to remove the insides of a spark plug. The inside is too hard for my drill.

    Help?
     
  2. Apr 25, 2016 #2

    Joe Fisher

    Joe Fisher

    Joe Fisher

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    Years ago to make a differential compression tester, I took a unshielded 18mm plug and broke the porselin with a hammer. Then brazed a pipe union to the steel.
     
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  3. Apr 25, 2016 #3

    kent Ashton

    kent Ashton

    kent Ashton

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    Much easier just to buy one. Do a google image search for Spark Plug Compression Adaptor. Many available
     
  4. Apr 25, 2016 #4

    PTAirco

    PTAirco

    PTAirco

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    I welded a grease (zerk) fitting to an old spark plug to unstick a very stuck piston. Had to smash out the insides with a punch and hammer.
     
  5. Apr 25, 2016 #5

    PTAirco

    PTAirco

    PTAirco

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    That sums up HBA!
     
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  6. Apr 25, 2016 #6

    Dan Thomas

    Dan Thomas

    Dan Thomas

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    If you look carefully you'll see that a sparkplug is actually two pieces of metal. The skinnier top part fits into the fatter lower part, and a collar around the top of the lower part is rolled over a lip on the top part to hold it there. You can grind that collar off, or stick the plug in a lathe and turn it off, and the top part will come off and let the ceramic fall out. Tap the bottom part for 1/4" NPT and you're done.

    See the joint?

    EditedPlugWCallouts.png

    SparkPlugTesting.jpg
     
  7. Apr 25, 2016 #7

    Vision_2012

    Vision_2012

    Vision_2012

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    Dan,
    Thanks!
     
  8. Apr 25, 2016 #8

    BoKu

    BoKu

    BoKu

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    Well, you kind of have to pick your battles. People who make their own screws instead of buying them for a nickel each rarely get finished and flying.
     
  9. Apr 26, 2016 #9

    cheapracer

    cheapracer

    cheapracer

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    Sure but who said finished and flying is everyone's primary goal. It's not of course.
     
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