Nissan SR20 (SR family, 1.8 and 2.0)

Nissan's 2.0 four — in the Primera and Sentra, and, as the turbocharged SR20DET, in the Silvia and 200SX.

⚑ It is one of the most heavily modified engines in this catalogue, and that changes the diagnosis before it starts. An SR20DET swapped into a car that left the factory with something else is common; so is a rebuilt engine whose stamped code no longer describes what is inside it. Confirm what is actually fitted before trusting any specification — compression ratio, fuel requirement and boost target all move.

On a standard engine the recurring items are ordinary. The crank angle sensor sits in the distributor and fails with heat, giving an intermittent stall and no-start that clears when cool; valve cover and oil pan gaskets leak with age; and the timing chain guides rattle on a cold start at high mileage.

Its known weakness is the oiling system under sustained high load, which is why bearing failures are discussed so much — but that is a track-use conversation, not a road-car one. On a standard car the oil interval is what matters, and on a modified one the oil system is a design question rather than a maintenance one.

The SR20VE is a variable-lift engine and behaves differently above its switch point; treating it as a plain SR20DE misreads what a loss of top-end power means.