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At Munro & Associates, Sandy Munro has earned a reputation for his no-nonsense engineering reviews. His teardowns spotlight critical insights into automotive design, cost optimization, and manufacturing efficiency. In a surprising turn, the latest teardown of the Ford Mach-E’s front motor system left Sandy genuinely impressed — a rare feat. Here’s why.
First Impressions: A Dramatic Turnaround for Ford
Sandy’s prior experiences with Ford’s electric powertrains were less than enthusiastic. However, the Mach-E’s front motor and inverter architecture signal a major leap forward. Right away, he notes the dramatic difference compared to earlier systems, showcasing superior lean design and thoughtful engineering.
The first standout? A look inside the gearbox. Ford’s design here is leaner, with fewer ball bearing races — four versus Tesla’s six — while still delivering robustness and simplicity. The Mach-E’s front motor, estimated at about 65 horsepower, is notably less complicated than its Tesla counterpart, yet remains highly efficient and durable.
Clever Gearbox Innovations
The Ford Mach-E front gearbox — supplied by Magna — is packed with clever engineering. Sandy highlights how the differential is ingeniously integrated within one of the gears, creating a compact and elegant solution. Unlike more traditional layouts, this approach saves space, reduces complexity, and enhances durability.
A key component drawing praise is the forged, machined one-piece output shaft. By eliminating welding, pressing, or freeze fits, this design greatly minimizes manufacturing risks and improves long-term reliability. Forged gears throughout the system reinforce the gearbox’s robust, cost-effective construction — a major win for lean manufacturing principles.
Gaskets Over RTV: A Smart Sealing Choice
Another detail Sandy admires is Ford’s decision to use gaskets rather than RTV (room-temperature vulcanizing) sealant. In high-precision environments like an electric motor, minimizing contamination risks from stray sealant is crucial. Using gaskets ensures cleaner assembly, better serviceability, and fewer potential failure points.
Stator Integration: Pressed In, Not Bolted
Ford’s stator design further illustrates the team’s engineering sophistication. Instead of relying on large bolts — a common approach in earlier designs — Ford presses the stator directly into the housing. This simplifies the assembly process, improves reliability, and reduces the potential for vibration-related failures.
Additionally, Ford opted to cool the stator using the vehicle’s existing coolant system rather than a separate oil circuit. This decision eliminates the need for auxiliary pumps and filters, saving weight, cost, and complexity. It’s a prime example of smart, system-level design optimization.
Hairpin Stator Reconsidered
Initially, Sandy lauded the Mach-E’s use of hairpin stator windings, noting their cost advantages. However, he shares updated insights: hairpin stators reportedly achieve only about 70% first-time manufacturing yield, compared to around 80–85% for traditional wound bobbin stators. Despite the higher potential for rework, the hairpin approach still offers benefits, particularly for mass production and cooling efficiency.
Importantly, Sandy highlights the importance of flexibility: as new information emerges, good engineers adapt. His candid admission of changing opinions based on new data is a reminder that dynamic, evidence-based thinking is essential in today’s rapidly evolving EV sector.
Rotor Lamination Details
Sandy also details the Mach-E front motor’s rotor construction. It features a double-V magnet configuration — similar to the rear motor but with subtle differences in angle and alignment for optimized performance. Neodymium magnets are glued in place with remarkable thoroughness, supplemented by mechanical tabs (“stitching”) to ensure stability during high-speed rotation.
The rotor uses 226 laminations stacked to a length of 61.5mm. Comparatively, the rear Mach-E motor’s rotor measures around 125mm, while Volkswagen‘s ID.4 rear motor reaches 174mm. These differences reflect strategic choices in motor power density and vehicle packaging across different EV models.
Minor Critiques: Coolant Hoses and Casting Choices
No design is perfect. Sandy points out a less-than-ideal crossover hose solution for the coolant system. Instead of a fully integrated casting, Ford opted for a simple hose workaround. While inelegant, Sandy concedes that sometimes practical realities of manufacturing and cost containment drive such decisions — especially when they don’t materially affect performance.
Inverter Teardown: A Huge Leap Forward
The front inverter teardown also drew strong praise from Sandy. Compared to the rear inverter’s complicated assembly — a nightmare of nuts, bolts, and finicky connections — the front inverter is a model of elegance and efficiency.
Instead of traditional soldered connections, the Mach-E’s front inverter uses vertical floating connectors. These allow blind assembly, saving time and reducing the risk of damaging delicate pins. It’s an approach widely favored in high-volume, high-quality manufacturing.
Moreover, the cooling path for the IGBTs (insulated-gate bipolar transistors) is ingeniously simple and robust. Coolant flows directly over heat-generating components in a precisely managed pattern, ensuring thermal stability without the need for excessive fasteners or fragile seals.
Fastener Count: A Big Win for Lean Design
Lean manufacturing principles shine in the fastener count comparison:
- Front Mach-E inverter: 47 internal fasteners, 24 external
- ID.4 inverter: 95 internal, 20 external
- Rear Mach-E inverter: 83 internal, 16 external
The Mach-E front inverter requires dramatically fewer fasteners, translating into faster assembly times, reduced manufacturing costs, and improved reliability.
Final Verdict: Ford and Magna Deliver
Sandy closes the teardown by praising Ford, Magna, and LG for their outstanding engineering work on the Mach-E front powertrain. From the elegant gearbox and robust output shaft to the smart inverter design, the system exemplifies how thoughtful engineering can drive cost, performance, and manufacturability improvements.
For automotive engineers, EV investors, and technology enthusiasts, the Mach-E’s front motor and inverter teardown offers a masterclass in lean design and system optimization.
The Mach-E Front Motor: Teardown Takeaways
- Forged, machined components: Reduce risk, enhance durability.
- Gasket sealing: Improves assembly cleanliness and reliability.
- Pressed stator design: Simplifies assembly, boosts long-term performance.
- Coolant-based cooling: Saves weight and system complexity.
- Vertical floating connectors: Revolutionize inverter assembly efficiency.
- Fewer fasteners: Accelerate manufacturing and reduce potential failures.
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