SECTION I · THE BRIEF
Brief #31304Updated 18 SEP 2026MENLO PARK, CALeverKHOSLA VENTURES
Employbl Company Profile

Staff Mechanical Engineer, Sealing Systems

Onsite power generation for the net-zero carbon grid.

Location
Menlo Park, CA
Company size
100–500
Posted
4d ago
Via
Lever
Section II · Full ProfileFree with an account
  • 01Comp band & equity packageLocked
  • 02Seniority & experience requirementsLocked
  • 03Interview process & rubricLocked
  • 04Hiring manager & team contextLocked
  • 05Growth trajectory in this roleLocked
  • 06Offer & decision timelineLocked

Free account · no card · 2 minutes

Staff Mechanical Engineer, Sealing Systems

Mainspring Energy· Menlo Park, CAView company profile


Job title
Staff Mechanical Engineer, Sealing Systems
Job location
Menlo Park, CA
Job description

About Mainspring

Mainspring Energy manufactures and delivers fuel-flexible, low-emissions local power solutions that rapidly add new capacity and deliver reliable, affordable, and sustainable electric power. The company began commercial shipments of its Mainspring Linear Generators in 2020 and today has hundreds of megawatts in advanced development and field operations for leading Fortune 500 companies, data centers, and utilities. Mainspring also partners with global energy leaders including AEP, NextEra Energy Resources, Schneider Electric, and more.

The core values that ground our work, guide our decisions, and connect us together:

  • Pragmatic Optimism
  • Excellence without Ego
  • Proactive Collaboration
Job Overview

The Rings team owns one of the hardest technical problems in the Linear Generator: a piston and ring system that seals without liquid lubricant. Getting this right is foundational to the product’s low emissions and maintenance business model. The design space is demanding, with complex sealing geometry, demanding thermal and pressure conditions, and material performance and system behavior that all need to be considered simultaneously. Progressing the ring service interval is one of the most important development programs at Mainspring. As a Staff Mechanical Engineer on this team, you will take ownership of a significant piece of that challenge.

What You’ll Do
  • Lead ring and piston development projects, including setting requirements and scope, developing novel designs, reviewing colleagues' designs and analyses in detail, and building production introduction plans

  • Design complex moving parts in the piston and ring system, from originating ideas through detailed design, build, test, and evaluation of performance

  • Assess and root cause failures that involve coupled thermal, structural, materials, and fluid interactions, balancing analysis with hands-on physical intuition

  • Design and run effective test campaigns, using both benchtop rigs and in-generator experiments, to validate designs and accelerate learning

  • Discover and define requirements on surrounding subsystems to improve ring and piston performance

  • Collaborate closely with a talented engineering team in a fast-paced, iterative environment to find the best solutions

  • What We’re Looking For
  • Master's degree in Mechanical Engineering or equivalent with at least eight years of experience, or a Ph.D. with at least five years of experience

  • A proactive and collaborative work style suited for a dynamic R&D environment where priorities can evolve as you learn, including comfort with problems that cross team boundaries and engineering disciplines

  • Experience designing high-performance, precision parts from R&D through to production release

  • Fluency in SolidWorks or a comparable CAD package. Comfortable using structural and thermal FEA as a design tool (Ansys is a plus)

  • Ability to generate 2D drawings for manufacturing, including comfort with GD&T

  • Excellent physical understanding and intuition in structural mechanics and heat transfer; strength in tribology, fluid mechanics, or thermodynamics is a plus

  • A systems approach to problem solving: Prefers to look at the whole system to identify negative interactions and opportunities for improvement

  • Nice to Have
  • Excellent understanding of thermodynamics, experience interacting with a complex thermodynamic system. Power generation, energy storage, and aerospace (especially turbomachinery or propulsion) are all extremely relevant

  • Experience designing for high-cycle fatigue and high-pressure, high-temperature environments. Experience with super alloys is a plus

  • Fluency in Python programming for data analysis, and experience developing and validating simplified models of systems and subsystems to inform failure analysis and design

  • View job listing ↗
    The Saturday Briefing

    Get the Saturday tech briefing

    New company profiles, funding moves, and who’s hiring across the market — every Saturday morning.

    Mainspring Energy headquarters

    Menlo Park, CA

    Company size

    100500 employees

    Founded

    2010

    Total raised

    $813,000,000

    View company profile ↗

    Funding rounds