Here's What It Takes to Redeem Ford's Underwhelming 2.0-Liter Zetec Engine

The 2.0-liter Ford Zetec four-cylinder engine saw widespread use in motorsport following its introduction in a number of 1990s Fords. SVT versions of the engine in the Focus eventually produced as much as 170 horsepower naturally aspirated from 2.0 liters of displacement, which is respectable. All that said, other dual overhead-cam four-cylinders from the likes of Honda have much better-flowing cylinder heads, and to get a Zetec even close to that takes a lot of skilled labor.

YouTube channel Josh’s Engine Rehab recently documented the process of boosting the flow of a Zetec head with some port and valve adjustment. He does a variety of work on different manufacturers' stuff, but it's mostly modifying heads for performance. He thought he could get this particular Zetec out of a Caterham Seven up to flow levels of a comparable Honda engine, but as it turns out, that might've been a little ambitious.

Cylinder head port flow is typically evaluated on a flow bench using cubic feet-per-minute as the unit of measure. The stock Ford head came in around 160 CFM on the intake and 129 CFM on the exhaust. After removing a lot of metal and making some other modifications, those figures were eventually boosted to 233 CFM on the intake and 204 CFM on the exhaust.