question about plenum
Thread Starter
Racer
Joined: Apr 2007
Posts: 292
Likes: 0
From: Houston texas
question about plenum
i bought a used plenum and received it with black stuff inside. oil or carbon buildup. is there suppose to be anything like that in the plenum? the reason i ask is because only air has gone through there. was there something wrong with it?
Melting Slicks
Joined: Apr 2002
Posts: 2,118
Likes: 0
From: St. Charles, MO Route 66 Corvette Club
The presence of black crap is "normal" inside the plenum of a L98 engine. It is caused by the evaporation of unburned fuel each time you shut down the engine. You cleaned plenum will look like this in a few months 
Melting Slicks
Joined: Apr 2002
Posts: 2,118
Likes: 0
From: St. Charles, MO Route 66 Corvette Club
Suggest you contact the person who will do the porting work for you and ask if it should be cleaned prior to shipping 
Their standard practice may be to clean the part upon arrival.
Their standard practice may be to clean the part upon arrival.
Race Director
Joined: Jun 2004
Posts: 13,961
Likes: 707
From: WI
I would think EGR would add more crud then unburned fuel. When I ported the plenum on mine it was VERY difficult to remove the carbon. I tried cleaners and also a wire brush, I ended up making some progress with a wire wheel on the die grinder.
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