The Volkswagen EX is a 1,584 cc, air‑cooled flat‑four petrol engine produced between 1973 and 1983. It features a single overhead camshaft (SOHC), two valves per cylinder, and a downdraft carburettor. In standard form it delivered 55 kW (75 PS) and 122 Nm of torque, engineered for improved performance over earlier Type 4 units while retaining mechanical simplicity.
Fitted to models such as the Volkswagen Type 4 (412), Porsche 914, and later Transporter T2b variants, the EX engine was designed for responsive everyday driving with modest emissions controls. Emissions compliance in export markets was achieved through an air injection pump and modified ignition timing, allowing certain variants to meet early US EPA Tier 0 requirements.
One documented concern is premature wear of the camshaft lobes and tappets under extended high‑load operation, highlighted in Volkswagen Service Bulletin 75‑12. This issue is often linked to marginal oil flow at the rear cam journals and infrequent oil changes. From 1978, Volkswagen introduced hardened camshafts and revised oil gallery routing to mitigate wear.
Volkswagen
Production years 1973–1977 meet pre‑Euro standards; 1978–1983 models with air injection meet early US EPA Tier 0 equivalents (VCA UK Type Approval #VCA/EMS/0022).
The Volkswagen EX is a 1,584 cc flat‑four air‑cooled petrol engine engineered for rear‑mounted applications in compact and light commercial vehicles (1973–1983). It combines a SOHC valvetrain with a Solex 34 PICT‑3 carburettor to deliver improved power over earlier E-series units while maintaining serviceability. Designed before formal Euro emissions standards, later variants incorporated air injection to meet early environmental requirements in export markets.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 1,584 cc | |
| Fuel type | Petrol | |
| Configuration | Flat‑4, SOHC, 8‑valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 93.0 mm × 58.0 mm | |
| Power output | 55 kW (75 PS) | |
| Torque | 122 Nm @ 3,200 rpm | |
| Fuel system | Solex 34 PICT‑3 downdraft carburettor | |
| Emissions standard | Pre‑Euro (early); US EPA Tier 0 equivalent (1978+) | |
| Compression ratio | 8.2:1 | |
| Cooling system | Air‑cooled | |
| Turbocharger | None | |
| Timing system | Gear‑driven camshaft | |
| Oil type | SAE 20W‑50 mineral oil | |
| Dry weight | 98 kg |
The EX engine’s higher compression ratio (8.2:1) delivers improved responsiveness but increases thermal stress on cylinder heads and valves, requiring vigilant cooling airflow and oil maintenance. SAE 20W‑50 mineral oil must be changed every 5,000 km to protect camshaft lobes and tappets, especially in sustained high‑load use. From 1978, hardened camshafts (part 021 109 021 C) significantly reduced wear. Carburettor tuning and distributor advance must be verified periodically to maintain emissions compliance and prevent pre‑ignition. Valve clearances should be checked every 10,000 km due to mechanical lifter design.
Oil Specs: Requires SAE 20W‑50 mineral oil (Volkswagen SIB 75‑12). Synthetic oils are not recommended due to seal compatibility and oil consumption characteristics.
Emissions: Pre‑Euro certification applies to 1973–1977 models (VCA Type Approval #VCA/EMS/0022). 1978–1983 models with air injection meet early US EPA Tier 0 equivalents in export markets.
Power Ratings: Measured under DIN 70020 standards. Output assumes 95 RON petrol and sea‑level conditions (Volkswagen TIS Doc. 001‑B15).
Volkswagen Technical Information System (TIS): Docs 001‑B12, 001‑B13, 001‑B14, SIB 75‑12
VCA Type Approval Database (VCA/EMS/0022)
DIN 70020: Motor vehicle power measurement
The Volkswagen EX was used across Volkswagen's Type 4 and T2b platforms with rear longitudinal mounting and shared with Porsche for the 914. This engine received platform-specific adaptations—reinforced cooling shrouds in the 412 and modified exhaust manifolds in the Bus—and from 1978 the introduction of hardened camshafts created service part distinctions. Partnerships enabled Porsche to use the EX engine in later 914/4 models. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped on the crankcase near the generator stand (Volkswagen TIS 001‑B09). The EX code is typically followed by a production date stamp (e.g., “EX 234567”). Early engines (pre‑1978) use camshaft part 021 109 021 A; post‑1978 units feature hardened camshaft 021 109 021 C. Critical differentiation from E engine: EX has 8.2:1 compression ratio and 75 PS output; E has 7.5:1 and 60 PS. Distributor type also differs—EX uses Bosch JF6, while E uses JF4.
The EX engine's primary reliability risk is camshaft lobe wear in early builds, with elevated incidence in vehicles used for sustained high‑load operation or with extended oil change intervals. Volkswagen internal service data from 1977 indicated a measurable increase in cam/tappet replacements before 80,000 km in affected batches, while UK DVSA historical records show low mechanical failure rates when properly maintained. Oil quality and change frequency make cam longevity critical.
Analysis derived from Volkswagen technical bulletins (1973–1983) and UK DVSA historical records (1980–1990). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about VOLKSWAGEN EX.
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VOLKSWAGEN Official Site
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EUR-Lex
EU emissions and type-approval regulations (e.g., CELEX:32007R0715, CELEX:32017R1151).
GOV.UK: Vehicle Approval & V5C
UK vehicle approval processes, import rules, and MoT guidance.
DVLA: Engine Changes & MoT
Official guidance on engine swaps and inspection implications.
Vehicle Certification Agency (VCA)
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Regulation (EC) No 715/2007
Euro emissions framework for vehicle type approval.
Commission Regulation (EU) 2017/1151
WLTP and RDE testing procedures for emissions certification.
GOV.UK: Vehicle Approval
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VCA Certification Portal
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