The Mazda B6 (SOHC) is a 1,597 cc, inline‑four naturally aspirated petrol engine produced between 1985 and 1994. It features a single overhead camshaft (SOHC) design with two valves per cylinder, prioritizing simplicity and low-end torque for urban driving. Output typically ranged from 55 kW (75 PS) to 66 kW (90 PS), with torque figures around 120–130 Nm, depending on the specific variant and market.
Fitted to popular models like the 323 (BF/BA), 121 (DA), and Ford Laser, the B6 (SOHC) was engineered for reliable, economical transportation. Emissions compliance for its era was managed through carburetion or throttle-body injection (TBI) systems, paired with basic catalytic converters, meeting applicable pre-Euro standards.
One documented service consideration is the potential for distributor shaft wear in high-mileage units, which can lead to ignition timing inaccuracies and misfires. This is addressed in Mazda service documentation, recommending inspection and replacement of the distributor assembly if excessive play is detected.
Mazda
Production years 1985–1994 meet applicable emissions standards for their respective markets at time of manufacture (Mazda Technical Service Information).
The Mazda B6 (SOHC) is a 1,597 cc inline‑four naturally aspirated petrol engine engineered for compact hatchbacks and sedans (1985-1994). It combines SOHC 8-valve architecture with carburetor or throttle-body injection to deliver robust low-end torque and exceptional fuel economy. Designed to meet the emissions regulations of its production era, it offers a simple and durable powertrain.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 1,597 cc | |
| Fuel type | Petrol | |
| Configuration | Inline‑4, SOHC, 8‑valve | |
| Aspiration | Naturally Aspirated | |
| Bore × stroke | 78.0 mm × 83.6 mm | |
| Power output | 55–66 kW (75–90 PS) | |
| Torque | 120–130 Nm @ 3,000–4,000 rpm | |
| Fuel system | Carburetor or Throttle Body Injection (TBI) | |
| Emissions standard | Market-specific (Pre-Euro standards) | |
| Compression ratio | 9.0:1 | |
| Cooling system | Water‑cooled | |
| Turbocharger | None | |
| Timing system | Belt-driven | |
| Oil type | SAE 10W-30 or 10W-40 (API SG/CD) | |
| Dry weight | Not publicly specified |
The SOHC 8-valve design provides strong low-RPM torque ideal for city driving but requires strict adherence to the 60,000 km timing belt replacement interval to prevent engine damage. Using the specified SAE 10W-30/40 oil is critical for maintaining hydraulic lifter function and overall engine longevity. The non-interference design offers a safety margin if the timing belt fails. Regular inspection of the distributor shaft for wear is advised to maintain accurate ignition timing.
Oil Specs: Requires SAE 10W-30 or 10W-40 meeting API SG/CD specification (Mazda Owner's Manual BF Series). Modern equivalents like API SN are acceptable if viscosity is correct.
Emissions: Pre-Euro certification applies to all models (Mazda Technical Service Information). Specific standards vary by country of sale.
Power Ratings: Measured under JIS or DIN standards depending on market (Mazda Global Product Catalogue 1990). Output varies by fuel system (carburetor vs. TBI) and regional emissions tuning.
Mazda Electronic Parts Catalogue (EPC): Doc. B6-SOHC-SPEC
Mazda Workshop Manual: BF/BA Series 323
Mazda Owner's Manual: BF Series 323
Mazda Global Product Catalogue (1990)
The Mazda B6 (SOHC) was used across Mazda's BF/BA and DA platforms with transverse mounting. This engine received minor revisions for different fuel systems (carburetor vs. TBI) and power outputs, creating subtle compatibility differences. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped on the front of the cylinder block, near the gearbox flange. The code will read "B6" followed by additional characters indicating specific variants (e.g., B6, B6-ME). The SOHC head is visually distinct from the DOHC B6 by its narrower, simpler cam cover. Differentiate from the turbocharged B6T by the absence of a turbocharger and associated plumbing. Critical service parts, like the timing belt kit, are generally consistent across all B6 (SOHC) applications, but gaskets and sensors may vary by model year and fuel system.
The B6 (SOHC)'s primary maintenance focus is the timing belt, with failure leading to engine stoppage. While non-interference, valve damage is possible. OEM service schedules are critical, as neglect is the leading cause of major issues. High-mileage units may develop distributor wear, making proactive replacement advisable.
Analysis derived from Mazda technical bulletins (1985-1994) and workshop manuals. Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about MAZDA B6-SOHC.
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Regulation (EC) No 715/2007
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Commission Regulation (EU) 2017/1151
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