Spark Plug Change (Petrol)

Accord 03-08 i-VTEC, K20A6

  1. Dom
    The car need a full service so rather than changing for the standard plugs this time went for an upgrade and used Iridium plugs.

    The standard plugs on the K20A engine are
    ZFR6K-11 (NGK)
    KJ20DR-M11 (DENSO)

    The petrol service schedule recommended they need to be replaced at 25000 miles or every two years which ever comes first. I have always carried a lot spare parts for my cars and there was no exception with ZFR6K-11 plugs I have used 4 sets till date.Now that I have depleted the last of these plugs and it perfect time to upgrade to the IZFR6K-11.These plugs are seen on the K24A engine and it is the same heat range and it make sense to upgrade to these plugs on the K20 engine. Goodbye 25000 mile changes :Wave:

    I prefer to use NGK plugs on my cars and always buy Honda Genuine NGK spark plugs to escape the huge counterfeit plug market.You can get the same iridium plugs in NGK OEM packaging which are slight cheaper than the Honda main dealers but they authenticity is always suspect.The Asian cloners are making perfect counterfeits it not worth the gamble to save a few pounds. There is no way the Honda supply chain is infiltrated with counterfeiters and all the parts are 100% GENUINE.:Thumbup:

    Check out these links to learn more how to spot the genuine and the fake ones.


    NGK Video

    The change on the K20 engine is relatively straight forward and easy.

    The Removal Process

    1) First remove the ignition coils cover (A)
    2) Disconnect the ignition coil connectors (B), and
    3) Then remove the ignition coils (C) ensure sure you replace the coils in their original position. I just lay them in front of the cam cover.
    4) If you have access to a compressor blow air into the the spark plug tubes to get the dust and any debris out before you remove the plugs.
    1 Ignition Coil Removal and Installation.JPG

    2 Coil cover removed 2.

    3 Coil cover removed.

    4 Coil cover removed 3.
    5) Remove the plugs and inspect them thoroughly.Inspect the electrodes and ceramic insulator. All the plugs removed from my car.

    5 Perfect Combustion.

    6 ZFR6K-11 (NGK).

    How to inspect spark plugs and interpret the colours?

    Burned or worn electrodes may be caused by:
    - Advanced ignition timing
    - Loose spark plug
    - Plug heat range too hot
    - Insufficient cooling

    Fouled plug may be caused by:
    - Retarded ignition timing
    - Oil in combustion chamber
    - Incorrect spark plug gap
    - Plug heat range too cold
    - Excessive idling/low speed running
    - Clogged air cleaner element
    - Deteriorated ignition coils
    NGK's superb guide of troubleshooting

    NGK PLUG Troubleshooting

    The installation
    1) Using a spark plug wrench with an extension rod remove and replace one plug at a time, This will ensure no debris blow or drop into the cylinder, especially if you are working out in the open.
    2)Screw the plugs into the cylinder head, finger-tight,then torque them to 18 N·m (1.8 kgf·m, 13 lbf·ft) using a calibrated torque wrench. You have to be careful to ensure the plugs are not cross threaded,novice users do take care a crossed thread plug will wreck your delicate aluminium head.

    The new versus old plugs
    7 IZFR6K-11 (NGK). 8 ZFR6K-11 (NGK)  & IZFR6K-11 (NGK).

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  1. aznspidey
    Not for my car model but good general info!
  2. jol
    Additional info -good!