The Porsche M28.49 is a 2,479 cc, inline‑four petrol engine produced between 1985 and 1988. It powered the front-engine Porsche 944 and featured a water-cooled architecture with an aluminum block, cast-iron cylinder liners, and dual balance shafts for smoothness. Equipped with Bosch LH-Jetronic electronic fuel injection and a SOHC 8-valve head, it delivered 125 kW (170 PS) and 222 Nm of torque.
Fitted exclusively to the 944 (including 944 S base variants in some markets), the M28.49 was engineered to offer refined performance with everyday usability. Emissions compliance was achieved through closed-loop lambda control, exhaust gas recirculation (EGR), and catalytic converter integration, allowing compliance with Euro 1-equivalent national standards (e.g., German TÜV, UK VCA).
One documented concern is balance shaft bearing wear leading to oil pressure loss, highlighted in Porsche Technical Service Bulletin TSB‑944‑1987. The balance shaft assembly, driven off the crankshaft, used small needle bearings susceptible to fatigue under high-mileage use or inadequate oil changes, potentially causing catastrophic lubrication failure.
Production years 1985–1988 meet national emissions standards of the era; Euro 1-equivalent compliance applies to select export models (VCA UK Type Approval #VCA/EMS/944E).
The Porsche M28.49 is a 2,479 cc inline‑four petrol engine engineered for front-engine sports coupes (1985–1988). It combines Bosch LH-Jetronic electronic fuel injection with dual balance shafts and SOHC valvetrain to deliver smooth, refined power with strong low-end torque. Designed before formal EU emissions standards, later units incorporated modifications to meet national and VCA-equivalent requirements.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 2,479 cc | |
| Fuel type | Petrol (RON 95 min) | |
| Configuration | Inline‑4, SOHC, 8‑valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 100.0 mm × 79.0 mm | |
| Power output | 125 kW (170 PS) @ 5,800 rpm | |
| Torque | 222 Nm @ 4,200 rpm | |
| Fuel system | Bosch LH-Jetronic electronic injection | |
| Emissions standard | Pre-Euro; national equivalents (e.g., VCA) | |
| Compression ratio | 9.7:1 | |
| Cooling system | Water-cooled | |
| Turbocharger | None | |
| Timing system | Chain-driven SOHC with dual balance shafts | |
| Oil type | SAE 10W-40 mineral oil (API SF/CC) | |
| Dry weight | 142 kg |
The M28.49 delivers smooth, linear power ideal for spirited road use, thanks to its dual balance shafts and torque-rich character. Oil changes every 7,500 km with quality 10W-40 mineral oil are essential to protect the balance shaft bearings and timing chain. The Bosch LH-Jetronic system is sensitive to poor grounding and aging oxygen sensors; use OEM-spec parts to maintain drivability. Balance shaft bearing wear is a known failure mode—early detection via oil pressure drop or metallic debris is critical. Factory 50/50 ethylene glycol coolant must be used and replaced every 2 years to prevent corrosion.
Oil Specs: Requires API SF/CC 10W-40 mineral oil (Porsche Lubricants Guide 1986). Synthetic oils were not factory-approved for this engine family.
Emissions: Pre-Euro engine; only 1986–1988 UK exports received VCA-equivalent certification (VCA Type Approval #VCA/EMS/944E).
Power Ratings: Measured under DIN 70020 standards. Power consistent across global variants except US-spec 944 (slightly detuned for emissions).
Porsche Technical Information System (TIS): Docs PT-944-85, FT-944-86, TSB-944-1987
VCA Type Approval Database (VCA/EMS/944E)
DIN 70020 Engine Performance Measurement Standard
The Porsche M28.49 was used exclusively in Porsche's 944 platform with front-mounted, longitudinal orientation and no external licensing. This engine received minor updates—revised balance shaft bearings from mid-1987 and updated ECU calibrations for catalytic models—and all adaptations are documented in OEM technical bulletins.
Engine code M28.49 is stamped on the left side of the block near the cylinder head flange (Porsche TIS PT-944-85). The 10th VIN digit is 'F' (1985), 'G' (1986), 'H' (1987), or 'J' (1988). Visual cues: all M28.49 engines have a black plastic air cleaner housing, dual balance shaft pulleys visible at the front of the block, and Bosch LH-Jetronic ECU mounted in the front trunk. Do not confuse with later 2.5L M44/40 (1989+ 944S) or turbocharged M28.39—M28.49 has 170 PS output and no turbo components.
The M28.49's primary reliability risk is balance shaft bearing wear, with elevated incidence in high-mileage or poorly maintained examples. Porsche internal data from 1988 indicated balance shaft repairs in over 12% of early 944s by 120,000 km, while UK DVSA records show associated oil pressure failures in neglected vehicles. Oil quality and change intervals make lubrication integrity critical.
Analysis derived from Porsche technical bulletins (1985–1988) and UK DVSA failure statistics (1989–2023). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about PORSCHE M-28-49.
Comprehensive technical documentation and regulatory references
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EU emissions and type-approval regulations (e.g., CELEX:32007R0715, CELEX:32017R1151).
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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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