Also known as: r18a, r20a, 1.8 i-vtec, 2.0 i-vtec, r18, civic 1.8, r18a2, r18a1, r18z1, r20a3, r18z9, r16a, r16b, r20z, r16, r20, r16a1, r20z1
Honda's 1.8 and 2.0 litre economy fours — the engine of the eighth- and ninth-generation Civic and of the CR-V, sitting below the K-series in the range and designed for efficiency rather than output.
The R18's distinguishing feature is an unusual form of i-VTEC that delays intake valve closing at light load to reduce pumping losses, effectively running an Atkinson-like cycle in cruise. That is worth knowing because it makes the engine's part-load behaviour and fuel trims look different from a conventional Honda four, and a fuel-trim reading interpreted by K-series expectations can mislead.
In service they are durable and undramatic. The complaints that recur are the VTEC spool valve screen and solenoid — clogged by neglected oil and producing a performance complaint with a system-level code — plus ignition coils and, at high mileage, valve clearance drifting out of specification. Honda engines of this era genuinely need their valve clearances checked, and a ticking or a misfire on a high-mileage R-series is often exactly that.
Cars fitted with this engine
9 generations, across 2 makes. From the authored catalogue — an absent car means the catalogue has not reached it, not that the engine was never fitted.
Acura
Information, not instruction
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