4381 - Champion Aerospace Slick Left Hand Rotation 5 Lag Impulse Coupled Magneto

4381 – Champion Aerospace Slick Magneto (Left-Hand Rotation)

Available now through the AirParts Aero marketplace.

Overview Section

The Champion Slick 4381 is a high-performance, Impulse-Coupled Magneto designed for 4-cylinder general aviation engines. Magnetos are self-contained ignition units that generate high-voltage electricity to fire the engine's spark plugs, operating independently of the aircraft's battery and alternator for maximum safety.

The 4381 model is specifically engineered for Left-Hand (LH) Rotation and features a 5-degree lag impulse coupling. This mechanical coupling is critical for engine starting; it momentarily "holds back" the magneto's rotation and then snaps it forward rapidly. This creates a high-intensity spark and retards the ignition timing by 5 degrees to prevent engine kickback during the low-RPM cranking phase of a start.

Key Features Section

• Impulse Coupling (5° Lag): Ensures a hot, retarded spark for easy starting and prevents backfiring during hand-propping or starter engagement.

• Independent Ignition: Operates completely separate from the aircraft electrical system, ensuring engine operation even in the event of a total electrical failure.

• Lightweight Design: Slick magnetos are significantly lighter and more compact than traditional "large-body" magnetos, reducing engine accessory weight.

• Heavy-Duty Internal Components: Features high-grade points, a robust coil, and a precision-balanced rotor for consistent firing at all power settings.

• Fully Shielded Housing: Designed to minimize Electro-Magnetic Interference (EMI) with avionics and radio communications.

• Standard 4-Cylinder Configuration: Optimized for the firing order and harmonics of common Lycoming and Continental 4-cylinder powerplants.

Technical Specifications Section

Aircraft Compatibility Section

The 4381 is a primary ignition source for many 4-cylinder engines, typically installed on the left side of the accessory case:

• Lycoming O-235, O-320, and O-360 Series: Found on the Cessna 152, 172 and Piper Cherokee fleet.

• Continental O-200 and IO-240: Used in many light sport and trainer aircraft.

• Experimental Aircraft: A standard choice for Van's RV and Grumman builders due to its reliability and ease of maintenance.

Technical Applications & Safety

The impulse coupling is a wear item. The "snap" you hear when pulling a propeller through by hand is the impulse coupling pawls engaging and releasing.

Safety Warning: Magneto Timing and Inspection. Proper internal timing (E-gap) and "timing to the engine" are critical. Incorrect timing can lead to high Cylinder Head Temperatures (CHT) and catastrophic engine detonation.7 Champion/Slick recommends a 500-hour inspection for all 4000-series magnetos.8 This inspection involves checking the points for pitting, verifying the health of the distributor block, and most importantly, inspecting the impulse coupling for "pawl wear" or spring fatigue.

Technical Engineering Insight

The engineering value of the Slick 4381 lies in its Self-Contained Power Generation. The unit contains a permanent magnet rotor that spins inside a soft iron core, creating a magnetic field. When the "points" open, the field collapses across a primary and secondary coil, stepping the voltage up from roughly 200V to over 20,000V. The 5-degree lag impulse coupling uses a coiled spring to store energy during the compression stroke and release it at the precise moment of Top Dead Center (TDC), overcoming the fact that magnetos naturally produce a weaker spark at very low starting RPMs.

Installation & Maintenance Addendum

1. Gasket Replacement: Always use a new LW-12681 (or equivalent) gasket when installing the magneto to prevent oil leaks from the accessory case.

2. P-Lead Security: Ensure the P-lead (the wire to the ignition switch) is secure. A disconnected P-lead means the magneto is "HOT," and the engine could start unexpectedly if the propeller is moved.10

   
   

   
   

3. Spark Plug Wires: When connecting the harness to the 4381, ensure the wires are routed to the correct cylinders according to the engine's firing order to prevent backfiring.

Description:     Slick Magneto (NEW)
Part Number:     4381
Approved Replacement for Part Number:     Lycoming Engines 66GC05SFNN, Champion Aerospace MK401, Kelly 4381R, ES4381
FAA-PMA Part Information: [Click Here]

NOTE: Please remove drive gears before returning Magneto cores for “Core Credit.”

These lightweight aircraft magnetos are being used by many new equipment manufacturers. Weigh only 3-3/4 lbs. compared to 6-1/4 lbs. for typical old-style magnetos.

In early 1988, Slick discontinued the sale of re-manufactured magnetos to offer new units only.

All units carry a one-year warranty after delivery to the user. These model magnetos are completely rebuildable. The old 4000/4100 series magnetos and the 600 series magnetos may not be returned as an exchange unit for a new magneto of the same model. Most other Magnetos may be returned for core credit.

Drive gears are not included. *When purchasing slick magneto separately gaskets are not included.

4300 series is a direct replacement for the previous 4200 series Magnetos.

Features

• Champion slick magnetos make timing, installation, inspection and maintenance simpler and more convenient than ever before, also incorporated mechanic-endorsed features to improve performance and service life
• Lift-off housing - internal timing is not disturbed during inspections
• Simplified internal timing - improved internal markings and unique slick E-gap tool make timing easier and more accurate
• Fully sealed bearings - keeps contaminants out and grease in for smoother operation and less maintenance
• Lower EMI levels - redesigned housing improves sealing and results in less radio noise



Specifications

• Rotation Lag: 5 deg
• Product Weight: 4.92 lbs
• Suitable for Use With: Lycoming O-235-L2C and O-235-N2C Series Aircraft Engine
• Domestic/Import: Domestic

Application Guide

Related Documents:
Slick Mandatory Service Bulletin: [Click Here]
Engine Application Guide: [Click Here]
Magneto Application: [Click Here]
Harness Application 5/8": [Click Here]
Harness Application 3/4": [Click Here]