Used Mazda RX-8 Crankshaft

The RX-8 uses a rotary engine (the Renesis 13B-MSP), which does not have a conventional piston-and-cylinder layout, so it does not use a crankshaft in the traditional sense. Instead of pistons driving a crankshaft, the rotary engine uses a triangular rotor turning on an eccentric shaft, which is the rotary equivalent of a crankshaft. If you need the central rotating component of your RX-8 engine, the part you are looking for is an eccentric shaft, not a crankshaft — search for that term when requesting quotes from breakers.

The RX-8 was produced in two generations: Series 1 (2003–2008) and Series 2 (2008–2012), and Mazda made changes to the 13B-MSP engine between these phases, as well as refinements within Series 1 itself. Confirming whether an eccentric shaft from a 2004 car will fit a 2007 car requires checking the engine code stamped on your unit, as internal dimensions and porting can differ between build years. Provide your registration or engine code to the breaker and ask them to match it precisely, as this is not a part where a rough year match is reliable.

No, trim levels like PZ, GT, Kuro, and R3 are specification packages relating to equipment, interior, and cosmetic features — they do not change the engine internals. All RX-8 trim levels used the same 13B-MSP Renesis rotary engine, so the eccentric shaft you need is determined entirely by your engine code and build year, not your trim. You can disregard trim when sourcing this part, though it is always worth confirming the engine code with the breaker against your registration.

The Series 1 and Series 2 RX-8 both use the 13B-MSP Renesis rotary engine, but Mazda made various internal revisions across the production run, and the Series 2 introduced changes aimed at improving reliability and emissions. Whether an eccentric shaft crosses the 2008 Series 1 to Series 2 boundary without issue is something you must confirm with the breaker against your specific registration and engine code, as this is a precision internal component where subtle machining differences matter. Do not assume interchangeability across that boundary without the breaker verifying the part numbers.

A part listed as an RX-8 crankshaft is almost certainly being mislabelled, since the rotary engine in the RX-8 does not use a crankshaft at all. The correct term for the equivalent rotating component is an eccentric shaft, and buying a mislabelled part risks receiving something entirely incorrect for your vehicle. Always search for 'RX-8 eccentric shaft' and confirm the engine code with the breaker before purchasing to ensure you receive the right part.

All UK-market RX-8 models used the same 13B-MSP engine with a single power output (192 PS in most markets), so there is no variation in eccentric shaft specification driven by power output on this model. The key detail to supply to the breaker is your engine code, which you can find on your V5C or via a VIN check, as this is the most reliable way to ensure an accurate match. Confirm the exact part number with the breaker against your registration before committing to a purchase.