Starters are one of those subsystems most people don’t think about until a problem arises. That’s a shame because bump starting your racecar to finish an endurance race is no fun (ask me how I know). All the glitz and glamor may be paid to the engine, but the motor playing second to it is just as important to fire up the band.
We had a chat with Tilton Engineering Chief Engineer Casey Lund, about just what goes into developing and testing starters that will stand the test of time, high compression engines and perform under pressure.
Tell us about the design architecture of a Tilton starter.
They are originally based on Hitachi OEM starter platforms that have a modular adapting nose design. This allowed the pinion and mounting nose block to be easily swapped to fit different applications (Ford/Chevy/Chrysler etc.). The modular nose mounting blocks also allow for different clocking of the starter motor and solenoid so that the end user can adjust for fitment, clearing frame rails and headers, etc.
Simplified 3D models are available for some configurations, allowing chassis builders to confirm the fit in their CAD assembly. Starters in the 4000 series are available in clockwise and counterclockwise rotations to allow for different mounting locations and applications. Installation drawings are available for download on our website.
On the 4000 series, the pinion is in the form of an “offset gear reduction” (OSGR). This means that the electric motor is offset to the pinion centerline. The armature gear drives larger gear that also contains the one way clutch and pinion. This offset allows us to mount the starter and tuck it in tight against the engine block or bellhousing/gearbox to reach a small diameter ring gear. This allows for the smallest flywheel/ring gear possible which allows the lowest ground clearance and minimizes the mass and moment of inertia of the flywheel. In racing, this is preferred for fast shifting and RPM matching between engine and drivetrain.
Tilton’s solenoids are a key part of the equation aren’t they?
Tilton Solenoid 54-422HD is now standard on all 4000 series starters. This solenoid is supplied direct to Tilton by a major OEM and uses a custom Tilton designed plunger that is 49 percent bigger than the original Hitachi plunger. This means more iron for the electromagnet and results in a very snappy actuation, kicking the pinion out hard for positive engagement with the ring gear while subsequently connecting power to the main electric motor to spin the engine. Multiple years of development and on track testing from the Baja 1000 to multiple 24 hour races have resulted in the most robust starter solenoid combination we have ever produced. They have proven to be very thermally stable and resistant to shorting due to vibrations.
Give us a breakdown of how Tilton starters are manufactured.
Current starter production starts with bulk shipments of the components made to Tilton Engineering specifications. The starters are assembled in large batches and all of the components are inspected for accuracy and consistency. Build manuals and drawings control each step of the process down to the thread locker and torque specifications. The mounting nose blocks are made in house on the Tilton CNC lathes and milling centers.
Tilton Engineering has employed a continual improvement philosophy based on use and feedback in some of the harshest environments for electro-mechanical devises. Specific improvements on internal insulation are included per the build manual to eliminate arcing and shorting with the high power demands and tight packaging. Historical learning on long term fatigue life of wire leads and transitions has led to applying anti-vibration/damping measures.
What does a Tilton starter have to go through in order to “Pass” all the testing?
Every starter unit is tested on a D&V ST16 test stand which has become the industry standard for automotive starter assemblies. This test stand (or dyno) is a computer controlled test stand that sequentially and systematically tests and energizes the solenoid and electric motor while the pinion engages and spins a gear on the machine with a controlled variable resistance. See ST-16 data sheet and spec sheet attached for more information.
Each starter unit is packaged and shipped with the actual test data summary sheet showing the performance data in graph form for quick reference. Any unit that falls outside of the set test parameters is automatically failed at the test stand and set aside for review. Performance characteristics are shown on the graph. This testing is done in accordance with the Japanese Industrial Standard JIS D1607.
Where else can we find Tilton starters other than racecars?
Because of the reputation for performance and durability Tilton Super starters are used throughout the world on racecars, race trucks, race boats, airplanes, helicopters, engine dynos, all the way down to remote engine/generator/pump stations in industrial farming applications.