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.40 DiamondFIRE Spark Plug

Name: .40 DiamondFIRE Spark Plug
Brand: E3
SKU: E3.40
Price: 8.49 USD
Availability: InStock

$8.49

SKU: E3.40

In Stock

Ships by Aug 29

Free Shipping over $200

$100 Minimum Order

30 Days Return

Description

The E3.40 Automotive Spark Plug is a direct replacement designed for various domestic applications from the 1960s to the early 1990s. It features a 14mm thread diameter, a 0.460-inch thread reach, and a taper seat, with a 5/8-inch hex size for installation. The plug incorporates E3's patented DiamondFIRE technology, utilizing a three-legged electrode design that aims to enhance heat transfer and promote greater turbulence within the combustion chamber. This construction is claimed to yield benefits such as increased power output, reduced fuel consumption, and improved hydrocarbon emissions over the long term. The E3.40 also features a unique ground electrode and a full-size center electrode. E3 guarantees optimal performance for a period of five years or 100,000 miles. This spark plug is a resistor type and has a fixed DiamondFIRE gap that cannot be adjusted.

Product descriptions are provided by our supplier partners and may not always be perfectly accurate. Not sure this fits? or call (760) 282-4645 and we’ll verify before you order.

Fitment

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Specifications

Brand	E3
Part Number	E3.40
Category	Ignitions and Electrical

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Built for enthusiasts. Every order is backed by our 30 day return window on eligible items. Unused and uninstalled products may be returned with approved RMA and no restocking fees when received in new condition. Orders placed through the MOTORMIA app with a complete build qualify for our Fitment Guarantee — free return shipping if the part doesn’t fit your exact setup. The guarantee covers fit only; installation must follow manufacturer instructions, and we recommend a qualified shop for parts marked Difficulty 4–5.

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Shipping

Orders are processed in 1–3 business days. In stock parts ship promptly from our partner network. Special-order items either aren’t currently stocked or are built to your spec — expect 4–6 weeks. If a part goes on backorder while your order is in the queue, we’ll reach out and work through discounted alternatives together.

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