Head Porting

CSVT Main   3L Conversion   Head Porting

A larger portion of this information was collected from Contour Enthusiast Group CEG

Original 3L port
 

Original 2.5L port
 
There are a couple things to decide before you begin porting:
  • Remove the heads?
  • Remove Valves?
  • How to get the LIM (Lower Intake Manifold) shape in the head? (Trace with a pen or use the Intake Plates *New*)
  • How to fill the 3L injector ports? (Aluminum Weld, JB Weld or Intake Plates *New*)

I opted to remove both heads for easier access to the ports.  On the first head I removed all of the valves - very time consuming 3 or 4 hours to remove and reinstall.  I would not recommend that unless you are having the head welded.

I was going to weld my ports originally, but I have a TIG welder with no MIG attachment.  The port is a little tight to TIG Weld in.  From what I read on CEG you can have a shop weld the port for 20 - 100 dollars.

One thing I found difficult right off was trying to accurately represent the LIM shape onto the head.  That is the original reason I started developing the Intake Plate.  The plate is the size and shape of the LIM and not the Gasket.  The ports in the gasket are larger then the ports in the LIM, so if you port to the gasket size you are just spending extra time.
 

Porting

  • Tracing the LIM shape onto the head:
    		•

    • Line up the LIM on the head and bolt it in position.  Take some time to make sure all ports are lined up correctly.  The bolt holes in the LIM are larger then the bolts so there is some slop.

    • Use a sharpie and trace the shape onto the head.  This is a little tricky trying to get the pen close enough to mark right where the LIM meets the head.

     

    		  
     
    • Cut out the port shape as best you can. Try and keep the top edge of the port as square as possible - this will help flow.
    • Notice on the lower left area by the new injector port, the die grinder popped out of the port and marred the surface of the head.  Needless to say you want to avoid this.
    • Verify that the shape is close to the shape of the LIM.
    • Port some more if needed.
    • Sand the port for a smoother finish.  **There are some debates over how smooth the finish should be, and if a finish that is too smooth slows flow.  According to the LIM you can be pretty smooth.
    		  
     
    • Here are most of the bits I used for the porting.
    • I found that the round end bit leaves a nicer transition from where you worked to where you did not - then a square end.
    • The sanding wheels (on the left) leave a smoother surface then the sanding barrels (in the middle).
    • The small bit was use to cut the injector port.
     
  • Using the Intake Plate:
    		•
    These are the intake plates.
    • The bolt holes in the plates are almost tight for alignment purposes.  This way the plates align themselves and you do not have to hope you got them close enough.
    		  
       
       
       
       
         
         
    Sealing the 3L injector Port
  • Using JB Weld:
    		•

    JB Kwik Weld - Very sloppy - but with a nicely made pocket it can turn out nice.  I did a poor job with this.

    		  

    JB Stick Weld - Very easy to control - just cut off a section, mix it up in your fingers and form it into place - it stays how you put it.
       
       
         
     
     
     

     

     

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