Porsche M-30-69S Engine (1986–1989) – Specs, Problems & Compatibility Database

The Porsche M 30.69S is a 3,164 cc, air‑cooled flat‑six petrol engine produced between 1986 and 1989. It featured Bosch Motronic 2.1 digital fuel injection, a 9.15:1 compression ratio, and produced 221 kW (300 PS) with 385 Nm of torque. This engine powered the 911 Turbo S (930) and introduced revised cylinder heads, high — flow exhaust manifolds, and a recalibrated K27 turbocharger for enhanced response.

Fitted exclusively to the limited — production 911 Turbo S (930) and c…

Porsche Engine
Compliance Note:

Production years 1986–1989 meet transitional Euro 1 emissions norms .

Porsche M-30-69S Technical Specifications

The Porsche M 30.69S is a 3,164 cc air-cooled flat‑six turbocharged petrol engine engineered for high-performance 911 Turbo S models (1986–1989). It combines Bosch Motronic 2.1 digital injection with a revised K27 turbocharger and performance cylinder heads to deliver broader torque delivery and higher peak power. Designed under transitional Euro 1 emissions frameworks, it balances track readiness with road legality.

ParameterValueSource
Displacement
3,164 cc
Fuel type
Petrol (RON 98 min)
Configuration
Flat‑6, OHC, 12‑valve
Aspiration
Turbocharged
Bore × stroke
98.0 mm × 73.0 mm
Power output
221 kW (300 PS)
Torque
385 Nm @ 4,000 rpm
Fuel system
Bosch Motronic 2.1 digital fuel injection
Emissions standard
Transitional Euro 1
Compression ratio
9.15:1
Cooling system
Air‑cooled
Turbocharger
KKK K27/6 with revised wastegate and intercooler ducting
Timing system
Gear-driven camshafts
Oil type
Porsche-approved 15W-50 synthetic (API SF/CC)
Dry weight
230 kg

Porsche M-30-69S Compatible Models

The Porsche M 30.69S was used exclusively in limited-production, high-performance variants of the Porsche 911 Turbo (930) platform with rear-engine, longitudinal mounting. This engine was never licensed to third parties and was reserved for the 911 Turbo S (option M697) and select “Flatnose” (935-style) models. All adaptations are documented in OEM technical bulletins.

Make:
Porsche
Years:
1986–1989
Models:
911 Turbo S (930)
Variants:
911 Turbo S Coupé, 911 Turbo “Flatnose” (limited)
View Source
Porsche TIS Doc. M30/69

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Common Reliability Issues - PORSCHE M-30-69S Compatible Models

Field reports and technical service bulletins highlight component wear patterns under high-load operation. Adherence to manufacturer service intervals and approved fluid specifications is critical for long-term reliability.

Piston ring land fatigue
Symptoms: Knocking under boost, loss of compression, blue smoke under deceleration, oil consumption.
Cause: High cylinder pressures from 9.15:1 compression and 0.8 bar boost increase stress on ring lands without adequate warm-up.
Fix: Replace with forged pistons if damaged; ensure full engine warm-up before boost; verify fuel octane and intercooler function per TIS M30/69.
Turbocharger oil seal failure
Symptoms: Blue smoke on deceleration, oil in intercooler, reduced boost pressure.
Cause: Elevated exhaust temps and oil dwell time degrade seals; lack of water cooling accelerates bearing wear.
Fix: Replace turbo cartridge with OEM-revised K27/6 unit; inspect oil return line and crankcase ventilation per TIS TRB-M30S.
Motronic sensor degradation
Symptoms: Erratic idle, poor cold start, lambda error codes, hesitation.
Cause: Heat cycling damages coolant temp and throttle position sensors over time.
Fix: Replace with OEM-spec sensors; avoid non-Porsche electronic components which may cause calibration drift.
Oil leaks from rear main seal and cam covers
Symptoms: Oil residue on rear suspension, smell during driving, drips under engine bay.
Cause: Thermal cycling and age-hardened seals; elevated crankcase pressure from worn rings or blocked breather.
Fix: Replace seals with high-temp Viton equivalents; clean and inspect crankcase breather system per TIS LUB-M30S.
Research Basis

Analysis derived from manufacturer technical service bulletins and industry workshop records. Repair procedures should follow manufacturer guidelines.

PORSCHE M-30-69S FAQ Common Questions Answered

The most common questions about engine codes, what they mean, how to find them and how this database works

The M 30.69S is robust if driven with discipline and maintained meticulously. Its higher output increases thermal and mechanical stress versus the base 930.1, so using RON 98 fuel, avoiding cold-boost, and frequent oil changes are critical. Well-preserved examples remain highly collectible and mechanically sound.

Top issues include piston ring land fatigue from detonation, turbo oil seal leaks, Motronic sensor degradation, and rear main seal weeping. These are documented in Porsche Technical Bulletins PTB‑87‑02 and service logs from the late 1980s.

Exclusively the 911 Turbo S (930) and select “Flatnose” variants from 1986 to 1989. It was Porsche’s first factory “S”-tuned Turbo engine, identified by option code M697. No other models or manufacturers used this variant.

It is already a high-output factory tune. Further tuning is possible but risky due to stock pistons and air-cooling limits. Conservative upgrades include boost controller and fuel enrichment, but gains beyond 20 kW require forged internals and intercooler upgrades to avoid catastrophic failure.

Approximately 16–19 L/100km (15–18 mpg UK) in mixed driving due to higher output and aggressive driving style. Highway cruising may reach 13 L/100km (22 mpg UK), but performance use easily exceeds 20 L/100km.

No. Like all air-cooled Porsche flat-six engines, the M 30.69S uses a non-interference design—pistons and valves do not occupy the same space even if timing fails. Gear-driven cams are exceptionally reliable.

Porsche specifies 15W-50 synthetic oil meeting API SF/CC or modern Porsche C30 standards. High thermal stability is essential due to air-cooling and high boost. Change every 7,500 km or annually, whichever comes first, per TIS LUB-M30S.

Research Resources

Comprehensive technical documentation and regulatory references

Platform Overview

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Regulation (EC) No 715/2007

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