OS Speed 12TZ Performance Crankshaft - OS21532120 by O.S. Engine  [OS21532120]

O.S. ENGINES CRANKSHAFT OS SPEED 12TZ SPEC-2
Price:
AUD$39.23
Brand:
O.S. Engine
Model:
OS21532120
GTIN:
4531028141520
Condition:
Brand New
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alt="O.S. ENGINES CRANKSHAFT OS SPEED 12TZ SPEC-2" title="O.S. ENGINES CRANKSHAFT OS SPEED 12TZ SPEC-2"

Performance crankshaft for 12TZ Spec-2 series

This crankshaft is an OEM-design replacement part for RC-scale nitro engines identified as OS Speed 12TZ Spec-2, intended for direct engine rebuilds and maintenance. It serves as the rotating core inside the engine case, providing the counterweight and journal surfaces required to convert piston motion into rotational output within a model engine.

Install the OS21532120 when restoring worn rotating components; check bearing fit and journal condition, and make sure mating surfaces are free of debris. Attention to these details helps the engine deliver consistent throttle response and reduced vibration in demanding runs.

While the crank itself does not alter carburation, fitting a straight, balanced shaft can stabilise mechanical timing and improve the engine's overall behaviour under acceleration.

Specifications

  • Item: Crankshaft, OS Speed 12TZ Spec-2
  • Model Number: OS21532120
  • Brand: O.S. Engine
  • Compatibility: OS Speed 12TZ series engines

Use this OS21532120 crankshaft for rebuilds of OS Speed 12TZ Spec-2 engines and verify bearing and seal condition when assembling.

Does this crank change engine response or power delivery?

A correctly installed and balanced crank helps maintain consistent mechanical timing, which can improve perceived throttle response, although it does not increase engine power by itself.

Will swapping to OS21532120 affect vibration levels?

Replacing a worn or damaged crankshaft with the OS21532120 typically reduces unwanted vibration and helps stabilise idle and mid-throttle behavior.

Are there tuning tips after installation?

After reassembly, check idle and acceleration; fine-tune needle settings only if the engine shows a noticeable change in response, and monitor temps during the first runs.

Is additional balancing recommended for high-performance use?

For aggressive use, verify the counterweight balance and consider light dynamic balancing if you detect residual vibration at higher RPM.

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