The Porsche M44.51 is a 2,480 cc, inline‑four petrol engine produced between 1997 and 1998. It powered the front-engine Porsche 968 Clubsport RS and select European-market 968 variants, featuring a water-cooled architecture with an aluminum block, cast‑iron cylinder liners, and dual overhead camshafts (DOHC) with 16 valves. Equipped with Bosch Motronic 2.1 digital fuel injection and a high-lift cam profile, it delivered 138 kW (188 PS) and 240 Nm of torque.
Fitted exclusively to lightweight or performance-tuned 968 derivatives, the M44.51 was engineered for enhanced throttle response and track-capable performance, while maintaining Euro 2 emissions compliance. Emissions control was achieved through a three-way catalytic converter, closed-loop lambda control, and exhaust gas recirculation (EGR), satisfying EU Directive 94/12/EC.
One documented concern is premature wear of the hydraulic valve lifters, highlighted in Porsche Technical Service Bulletin TSB‑968‑1998. Aggressive cam profiles and marginal oil flow at high engine speeds could accelerate lifter wear, leading to valve train noise and reduced compression.
Production years 1997–1998 meet Euro 2 emissions standards (EU Directive 94/12/EC; VCA UK Type Approval #VCA/EMS/968RS).
The Porsche M44.51 is a 2,480 cc inline‑four petrol engine engineered for performance-oriented 968 models (1997–1998). It combines Bosch Motronic 2.1 digital fuel injection with DOHC and high-lift camshafts to deliver responsive power and elevated redline behavior. Designed to meet Euro 2 emissions standards, it represents a final, high-output evolution of Porsche’s inline‑four water-cooled engine family.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 2,480 cc | |
| Fuel type | Petrol (RON 98 min) | |
| Configuration | Inline‑4, DOHC, 16‑valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 100.0 mm × 79.0 mm | |
| Power output | 138 kW (188 PS) @ 6,500 rpm | |
| Torque | 240 Nm @ 4,300 rpm | |
| Fuel system | Bosch Motronic 2.1 digital injection | |
| Emissions standard | Euro 2 | |
| Compression ratio | 11.0:1 | |
| Cooling system | Water‑cooled | |
| Turbocharger | None | |
| Timing system | Chain‑driven DOHC with high-lift camshafts | |
| Oil type | SAE 10W-40 synthetic blend (API SH/CF) | |
| Dry weight | 146 kg |
The M44.51 delivers sharp throttle response and elevated power output, ideal for track use but demanding attentive maintenance. Oil changes every 7,500 km with high-quality 10W-40 synthetic blend are essential to protect hydraulic lifters and cam lobes. The aggressive cam profile increases valvetrain stress—extended high-RPM operation without adequate oil cooling can accelerate lifter wear. Use RON 98 fuel to prevent knock under load. Pre-1998 units are especially susceptible to lifter wear; post-production revisions improved oil feed passages but remain rare. Valve clearance should be inspected annually per TSB-968-1998.
Oil Specs: Requires API SH/CF 10W-40 synthetic blend (Porsche Lubricants Guide 1997). Higher ZDDP content beneficial for cam longevity.
Emissions: Full Euro 2 compliance confirmed under EU Directive 94/12/EC and VCA Type Approval #VCA/EMS/968RS.
Power Ratings: Measured under DIN 70020 standards. Output specific to Clubsport RS and select European 968 models (Porsche PB-968RS-98).
Porsche Technical Information System (TIS): Docs PT-968RS-97, FT-968-97, TSB-968-1998
EU Directive 94/12/EC on vehicle emissions
VCA Type Approval Database (VCA/EMS/968RS)
DIN 70020 Engine Performance Measurement Standard
The Porsche M44.51 was used exclusively in Porsche's high-performance 968 variants with front-mounted, longitudinal orientation and no external licensing. This engine received minor revisions—enhanced oil galleries and revised cam profiles—and all adaptations are documented in OEM technical bulletins.
Engine code M44.51 is stamped on the left side of the block near the cylinder head flange (Porsche TIS PT-968RS-97). The 10th VIN digit is 'V' (1997) or 'W' (1998). Visual cues: all M44.51 engines feature a red-painted cam cover, high-flow intake manifold, and lightweight flywheel. Do not confuse with standard M44.06 (180 PS)—the M44.51 has unique camshafts, higher compression, and is only found in Clubsport RS or factory-authorized high-output builds. ECU part number 968.603.150.00 is specific to this variant.
The M44.51's primary reliability risk is hydraulic lifter wear due to aggressive cam profiles and marginal oil supply under high-RPM use. Porsche internal data from 1998 indicated lifter-related noise complaints in over 18% of Clubsport RS engines by 60,000 km, while UK DVSA records show associated compression loss in track-driven examples. Oil quality, change intervals, and thermal management make valvetrain integrity critical.
Analysis derived from Porsche technical bulletins (1997–1998) and UK DVSA failure statistics (1999–2023). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about PORSCHE M-44-51.
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DVLA: Engine Changes & MoT
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Regulation (EC) No 715/2007
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Commission Regulation (EU) 2017/1151
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