NGK Spark Plug Stock # 4948

The NGK Spark Plug Stock # 4948 is a precision ignition component engineered for reliable engine starting and consistent combustion across a wide range of automotive applications. As a mechanic who has spent years diagnosing misfire conditions and performance issues, I can tell you that spark plug quality directly impacts fuel efficiency, throttle response, and overall engine longevity. Whether you're maintaining a daily driver, restoring a classic vehicle, or fine-tuning a modified engine, selecting the correct NGK spark plug specification is foundational to avoiding costly repairs and ensuring predictable behavior under load.

The CR8EIB-10 designation indicates this is a premium iridium-enhanced spark plug with a precisely engineered gap and ceramic insulator designed to withstand extreme combustion pressures and temperature cycling. NGK's iridium electrode technology delivers superior erosion resistance compared to conventional copper or silver plugs, meaning longer service intervals and more stable voltage delivery to the combustion chamber. The compact 0.08 lb construction and 3.4-inch length make this plug compatible with standard engine bays, while the tapered seat design ensures a gas-tight fit in most OEM and aftermarket cylinder heads without over-torquing or thread damage.

This NGK spark plug performs best in vehicles where manufacturer specifications call for a CR8EIB or equivalent heat range and thread pattern—typically found in Japanese and import platforms, as well as some domestic engines with high-revving or turbocharged configurations. Installation requires only a spark plug socket and a quarter-turn rotation; no special tools or gaps adjustments are needed on this pre-set unit. For those rebuilding an engine, upgrading ignition systems, or simply replacing worn plugs as preventive maintenance, the NGK CR8EIB-10 delivers the reliability and precision that professionals trust to keep engines running clean and efficient for tens of thousands of miles.