The Lycoming aviation spark plug, part number 66JR37SCNN, is a critical component within the engine's ignition system, responsible for initiating combustion in the cylinders by generating a precisely timed electrical spark.
This spark plug is engineered to withstand the demanding conditions of high-performance aircraft engines, ensuring reliable ignition of the fuel-air mixture under varying operational loads and altitudes. Its robust construction and specific heat range are tailored for optimal performance in the specified Lycoming engine series.
Overview
The aviation spark plug, designated by part number 66JR37SCNN, serves as the terminal point of the high-voltage ignition circuit in reciprocating aircraft engines. It is screwed into the cylinder head, positioning its electrodes within the combustion chamber. When energized by the magneto system, it creates an arc across a precisely set gap, igniting the compressed fuel-air charge and driving the engine's power stroke. This specific plug design is part of the overall ignition system, designed for optimal performance and longevity in its intended engine applications.
Specifications
- Type: Aviation Resistor Spark Plug, Shielded
- Thread Size: 18mm x 1.5 (Nominal)
- Thread Reach: Approximately 13/16 inch (0.8125 inches)
- Hex Size
- Stock: Out of Stock - On Backorder
- Manufacturer Part #: 66JR37SCNN
- Part#: 66JR37SCNN
Aircraft Fitment Finder
Returns & refund summary
- 30-day return window — with prior return authorization, unopened in original packaging.
- Restocking fee: 20% on unopened items, 30% on open-box items.
- Refund processing fee: 5.51% applies to all refunds (returns, cancellations, core-fee refunds) regardless of reason.
- Return shipping: paid by buyer.
- Non-returnable categories: installed/used parts, special-order or rebuilt items, programmed items (incl. ELTs), batteries, AOG-priority orders, international orders.
Full terms: Return Policy.
Authenticity & authorization
All parts sold by American Aviation Parts are genuine factory products sourced through authorized distribution channels. Our authorization status varies by brand — for some brands we are a direct authorized dealer; for others we are an independent reseller through authorized distribution. Either way, the part you receive is the same factory product, with standard documentation available on request.
See our full Manufacturer Authorizations page for the current per-brand status.
Need traceability paperwork?
If your installation requires FAA Form 8130-3, manufacturer Certificate of Conformance, or other traceability documentation, please call 1-877-722-8727 or email [email protected] before placing the order so we can confirm what is available for this part.
Shipping
Standard ground, expedited, and AOG shipping options are available at checkout. Full shipping-cost tiers and timelines are published on our Delivery Information page.
