intake manifold

[mocar]

Have a cast iron intake manifold , inside the manifold in the runners there is dark brown coloration, I assume that this is rust because the manifold has been sitting for some time. My question is how to get the surface rust out of the runners? Thanks in advance.

 

[Mr Gorsky]

Evaporust.

 

[JBurch]

Sand/shot/bead blast........take your pick

 

[furrystump]

Molasses and a bunch of time.

 

[rumblefish360]

Evaporust.

Sand/shot/bead blast........take your pick

And when your done with those & it is still there, forget you ever seen it and just use it.
;)