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Old 12-04-2012, 02:48 PM
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Zooks527 Zooks527 is online now
M235xi currently at sea
Location: Mansfield, MA
 
Join Date: Mar 2009
Posts: 4,288
Mein Auto: 2004 VW Passat 4mo
Quote:
Originally Posted by MP3_E46 View Post
Hmm.. I'd not thought of that before. So this is an air intake valve on a DI car? Presumably the carbon is sucked in from the combustion chamber and builds up over time?
Reburn from the PCV line. The crankcase vents into the intake with oil vapor in it. Most of the vapor is burned in the combustion cycle, but some carbonizes on contact with the hot metal around the valve. Another bit of anti-pollution joy.

In a Port Injection system, the fuel contacts the valve stem and helps keep it clean. In a Direct Injection system, you don't get this effect.


Extra credit: Complete this jingle: "We're the rocker arm assembly, assembly, assembly; we're the rocker arm assembly, and ...."
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Last edited by Zooks527; 12-04-2012 at 02:55 PM.
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