Intake Manifold crud??

[s car go]

Hi All
Took the head off my truck yesterday,and the inside of the intake manifold and ports is caked in about a 5 mm deep layer of black crud. I am assuming this is soot brought in from the EGR valve,but can anyone suggest why this would build up like this so badly??

Cheers

Mark

[tweak'e]

you assume correctly.
its build up of soot from egr, fine dust that gets through any air filter and oil from engine breather.
5mm is fairly good ! plenty get a lot worse than that.

thats why we block off egr systems and use catch cans on the breather.

water/alcohol injection systems are really good for keeping it clean.

[s car go]

you assume correctly.
its build up of soot from egr, fine dust that gets through any air filter and oil from engine breather.
5mm is fairly good ! plenty get a lot worse than that.

thats why we block off egr systems and use catch cans on the breather.

water/alcohol injection systems are really good for keeping it clean.

Hmm!,so the EGR,designed to help with emmisions,is starting to strangle the engines air suppy and increase emmissions!! OK need to find some plate and blank it off,it will make putting it all back together easier anyway.

Cheers

[tweak'e]

Hmm!,so the EGR,designed to help with emmisions,is starting to strangle the engines air suppy and increase emmissions!!
Cheers

exactly. some engines make less emissions with egr blanked off than they do with it working due to the build up.

the only thing i don't know with those engines is how to get around the throttle butterfly setup.