NGK Iridium Ignition Spark Plug - 90654

NGK SILZKFR8E7S / 90654 Iridium Ignition Spark Plug Replaces 004 159 70 03. With the smallest tip ...

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Ngk Silzkfr8e7s 90654 Spark Plug Laser Iridium New Ngk-Silzkfr8e7s Small

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Product Information

Full details

The NGK SILZKFR8E7S (90654) Iridium Ignition Spark Plug is designed for automotive enthusiasts and DIY mechanics looking to restore or maintain optimal engine performance with an OEM-standard component. Featuring the smallest available tip diameter, these plugs offer superior ignitability and a significantly longer service life compared to standard copper options. While these plugs provide excellent fuel efficiency and smoother idling, users must verify engine compatibility against their vehicle's specific manual, as improper fitment can result in poor performance or engine damage.

All features

Model Part Number	NGK-SILZKFR8E7S
Brand	NGK

Extended Product Information

FAQs

What is the spanner size for this plug?

This plug requires a 14mm spanner size.

Can I adjust the gap on this iridium plug?

It is generally not recommended to adjust the gap on iridium plugs as the fine-wire center electrode is fragile and easily damaged.

What material is the center electrode?

The center electrode tip is made of laser-welded iridium.

Does this plug come pre-gapped?

Yes, NGK Iridium plugs are typically pre-gapped, but you should always verify the gap against your vehicle's specifications before installation.

What is the thread length of the SILZKFR8E7S?

The thread length is 26.5 mm.

How does the platinum disc help?

The platinum disc on the ground electrode acts as a wear-resistant surface, allowing for longer intervals between plug changes.

Troubleshooting

Engine misfiring after installation

Verify the plug is fully seated and the ignition coil is firmly connected to the ring-type connector.

Rough idle persists

Ensure the spark plug gap has not been inadvertently altered during installation and check that the ignition wires or coils are in good condition.

Difficulty removing old plug

Use a penetrating oil if the plug is seized; allow time for it to soak before applying torque to prevent thread damage.

Pros and Cons

Pros

Extended service intervals due to iridium/platinum durability
Superior anti-corrosion properties from trivalent plating
Enhanced ignitability leads to smoother throttle response
OEM-approved design ensures exact fitment when matched correctly
Helps maintain lower vehicle emissions

Cons

Requires precise torque installation to avoid damage
Not compatible with every engine type; requires careful cross-referencing
More expensive than standard nickel or copper spark plugs

Setup, Compatibility & Care

Proper installation is critical for the performance of the SILZKFR8E7S.

Verification: Always cross-reference the `90654` part number with your vehicle's service manual or the manufacturer's compatibility list before purchase.
Installation: Use a 14mm spark plug socket. Since these plugs feature a copper gasket, ensure the threads are clean and free of debris before threading by hand to avoid cross-threading.
Torque: Tighten to manufacturer-recommended specifications. Over-tightening can crack the ceramic insulator.
Maintenance: While Iridium plugs are long-lived, inspect them during scheduled vehicle maintenance intervals to ensure there is no excessive electrode erosion or heavy carbon buildup.