Honda’s first engine CVCC (what is CVCC)
CVCC means Compound vortex controlled combustion.The CVCC engine debuted in 1975. Offered alongside the standard Civic engine, the 53-horsepower CVCC engine displaced 1,488 cc and had a head design that promoted cleaner, more efficient combustion. The CVCC design eliminated a need for a catalytic converter or unleaded fuel to meet emissions standards. (Nearly every other U.S. market car for this year underwent the change to exhaust catalysts and the requirement to use only unleaded fuel.) Due to California’s stricter emissions standards, only the Civic CVCC was available in that state. A five-speed manual gearbox became available this year, as did a Civic station wagon (only with the CVCC engine).
A CVCC engine has a special cylinder head. The CVCC head uses a stratified charge combustion chamber. A stratified combustion mixture is richer at the sparkplug and much leaner at the main part of the combustion chamber. The rich mixture is easily ignited by the sparkplug and this initial flame will ignite the remaining leaner mixture. The CVCC head uses a pre-combustion chamber that is about the size of a thimble. The CVCC carburetor is actually two carburetors in one, a lean part and a rich part. The lean part feeds the main combustion chamber and the rich part feeds the pre-combustion chamber. The rich mixture in the pre-combustion chamber is ignited . A “flame hole” in the pre-combustion chamber allows the pre-combustion flame to blow across the regular combustion chamber and ignite the lean mixture.
How to identify a CVCC:
-1500cc engine, designated ED1
-They say CVCC on the rocker cover
-The hose for the air filter goes to driver’s side fender
-2.17″ length increase in the front fenders to accommodate the larger CVCC engine
-Water pump is on the back drivers side and alternator is on the front
-3 spoke steering wheel (either wood grain or black)
-5 speed CVCC’s have a deluxe gauge cluster- Tach/Speedo and Fuel/Temp gauges on the center of the dash
-Hood has a split scoop type vent in front of the wind shield on later models.
-Rear struts on the hatch & coupe models are straight and similar in design to the front. Un-likethe 1200 models have a U-shape bracket welded to the bottom.
How The CVCC Engine Operates
Suction Stroke
On the intake stroke, a large amount of very lean mixture is drawn through the main intake valve into the main combustion chamber. At the same time, a very small amount of rich mixture is drawn through the auxiliary intake valve into the pre-chamber.
Compression Stroke
At the end of the compression stroke, a rich mixture is present in the pre-chamber, a moderate mixture is formed in the main combustion chamber near the pre-chamber outlet, and a very lean mixture is present in the remainder of the main combustion chamber.
Ignition
When the spark plug fires, the rich mixture in the pre-chamber is easily ignited.
Expansion Stroke
The flame from the pre-chamber ignites the moderate mixture and this, in turn, ignites the lean mixture in the main combustion chamber. The formation of carbon monoxide is minimized because of this lean mixture.
Bottom Dead Center
The stable and slow burning in the main combustion chamber has two desired effects. The peak temperature stays low enough to minimize the formation of oxides of nitrogen. And the mean temperature is maintained high enough and long enough to substantially reduce hydrocarbon emissions.
Exhaust Stroke
The hot gases exit through the exhaust valve, and oxidation continues in the manifold.
