The Mazda BP is a 1,839 cc, inline‑four naturally aspirated petrol engine produced between 1989 and 1998. It features a dual overhead camshaft (DOHC) and 16 valves, delivering a sporty character for its era with outputs up to 105 kW (142 PS). This engine prioritised responsive performance, using a multi-point fuel injection system for precise fuel delivery and throttle response.
Fitted to iconic models like the MX-5 (NA), 323F (BA), and Familia GT-X, the BP was engineered for enthusiasts seeking agile handling and rev-happy performance. Emissions compliance for its production period was managed through its electronic fuel injection and catalytic converter system, meeting applicable local market standards (pre-Euro norms) at the time of manufacture.
One documented service concern is potential wear in the hydraulic tensioner for the timing belt, which can lead to belt slippage or failure if neglected. This issue, noted in Mazda workshop documentation for the BA and NA platforms, is often related to extended service intervals. The engine received a minor update in 1993, revising the cylinder head casting and camshaft profiles for improved emissions and mid-range torque.
Mazda
Production years 1989–1998 meet applicable local emissions standards for their respective markets at time of manufacture (Reference: Mazda EPC, Model Year Specifications).
The Mazda BP is a 1,839 cc inline‑four naturally aspirated petrol engine engineered for sporty compact cars and roadsters (1989-1998). It combines a DOHC 16-valve design with multi-point fuel injection to deliver responsive, high-revving performance. Designed to meet local emissions standards of its production era, it offers an engaging driving experience balanced with reasonable economy.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 1,839 cc | |
| Fuel type | Petrol | |
| Configuration | Inline‑4, DOHC, 16‑valve | |
| Aspiration | Naturally Aspirated | |
| Bore × stroke | 83.0 mm × 85.0 mm | |
| Power output | 85–105 kW (115–142 PS) | |
| Torque | 150–162 Nm @ 5,000–5,500 rpm | |
| Fuel system | Multi-Point Fuel Injection (MPFI) | |
| Emissions standard | Local Market Standards (Pre-Euro) | |
| Compression ratio | 9.4:1 (early) / 9.0:1 (late) | |
| Cooling system | Water‑cooled | |
| Turbocharger | None | |
| Timing system | Belt-driven | |
| Oil type | SAE 10W-30 or 5W-30 | |
| Dry weight | Not Available |
The DOHC 16-valve design provides excellent high-RPM power, making it ideal for spirited driving. Adherence to the 60,000 km timing belt replacement interval is critical to prevent catastrophic engine damage, as this is an interference engine. Using the correct SAE 10W-30 or 5W-30 oil is essential for proper hydraulic tensioner and lifter operation. The MPFI system is generally robust but benefits from clean fuel and periodic injector cleaning.
Oil Specs: Requires SAE 10W-30 or 5W-30 mineral/semi-synthetic oil (Mazda Owner's Manual BA/NA Series). API SG/SH specification recommended.
Emissions: Certification based on local market regulations applicable at time of manufacture (Mazda Model Year Specifications). Pre-dates standardized Euro norms.
Power Ratings: Measured under JIS D 1001 standards. Output varies by model (e.g., MX-5 vs 323F) and market (Mazda Model Year Specifications 1993).
Mazda Workshop Manual (BA/NA Series)
Mazda Electronic Parts Catalogue (EPC) Doc. BP-01
Mazda Owner's Manual (BA/NA Series)
Mazda Model Year Specifications (1993)
The Mazda BP was used across Mazda's BA and NA platforms with transverse and longitudinal mounting respectively. This engine featured specific intake manifolds and ECU calibrations for different model applications. From 1993, a revised cylinder head with different cam profiles was introduced for the 323F GT-X and later MX-5 models, creating minor interchange limits. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped on the flat machined surface at the front of the engine block, near the timing cover (Mazda Workshop Manual BA/NA Series). The 8th digit of the VIN typically indicates engine type for Mazda-badged vehicles ('P' often denotes BP engine family). The BP can be visually identified by its DOHC valve cover and multi-point fuel injection rail. Critical differentiation from the B6 engine: The BP has a larger displacement (1.8L vs 1.6L) and distinct cam cover shape. Post-1993 models have a slightly different head casting. Always verify the engine code stamp for absolute identification before ordering parts.
The BP's primary reliability risk is timing belt failure due to neglected replacement intervals, which will cause catastrophic engine damage as it is an interference design. Mazda service data indicates this is the most common cause of major engine failure for this model. The hydraulic timing belt tensioner is a known wear item; failure can lead to rapid belt degradation. Adherence to the basic service schedule is critical for longevity.
Analysis derived from Mazda technical bulletins (1989-1998) and aggregated owner repair data. Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about MAZDA BP-DOHC.
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DVLA: Engine Changes & MoT
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Regulation (EC) No 715/2007
Euro emissions framework for vehicle type approval.
Commission Regulation (EU) 2017/1151
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GOV.UK: Vehicle Approval
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