EGR valve spindle was a ground-breaker

Posted by zjautopartsLee on January 27th, 2016

EGR valve spindle was a ground-breaker because it included a vane in the exhaust port flow that was designed to reduce turbulence. This vane, which is frequently removed by head porters, gives the port a "C" shape as opposed to the "D" shape it would have without the vane. So the same port configuration is alternately described as a "D" port with a vane or as a "C" port.

Bow Tie aluminum heads with rectangular exhaust ports and vanes in the floor are often referred to as "W" ports. However, the "W" may look like a "C" to some people, so the question then becomes is a "C" port a "D" port with a vane or a rectangular port with a vane? Typically, the "C" designation applies to the production heads, while the "W" is reserved for Bow Tie heads.

Think of it this way: The accumulation of the valve and all the reciprocating accoutrement of the valvetrain affect the armament in the system. The dispatch and force of the arrangement are dictated by the camshaft affiliate profile—or the bulk at which the affiliate moves the hydraulic lifter—so a authentic antithesis of basal mass, stiffness, accustomed frequency, cam-lobe acceleration, and armament accomplished in the arrangement is analytical to high-rpm valvetrain stability.

That's why artlessly replacing the Valve seat with those with a altered accumulation has cogent implications on performance: It upsets the antithesis that was congenital into the arrangement in the aboriginal place.