Verify the individual car
This page describes a model, engine or historical subject at archive level. Before using a specification for purchase, valuation or repair, confirm the chassis identity, production date, market version and installed parts of the individual car. Previous repairs and conversions can change what is present. Use the linked factory material for exact procedures and record measurements and observations rather than relying on appearance alone.
One family, distinct characters
The 2.0-litre M20B20 values smoothness, the 2.3 and 2.5 add urgency, and the long-stroke 2.7-litre eta trades revs for low-speed torque and economy. Buying by badge alone is therefore misleading: gearing, market specification, engine management and maintenance condition all shape how an M20 E30 feels.
The timing-belt rule
A missing invoice means the belt, tensioner and usually the water pump belong at the top of the job list. Age is as relevant as distance. The M20 is an interference engine, so postponing this service can turn a modest preventive job into cylinder-head repair.
Listen, inspect, verify
A light, regular valve tick can be normal; heavy knocking, persistent blue smoke or coolant pressure is not. Verify cold start, hot restart, stable idle and clean acceleration under load. Oil around the rocker cover is common and fixable, while emulsified oil, repeated overheating or unexplained coolant loss requires deeper diagnosis.