How to Align ITBs and Cut Throttle Shafts to Length
This article applies to Extrudabody's universal kits only.  If you are buying a kit from us that includes a manifold, then we'll take care of alignment for you.  The best quality manifolds will not require any special effort to properly align ITBs.  However, the quality of cast manifolds varies dramatically, so the instructions below will help create an ITB setup that performs no matter what manifold you have.  Also note that our system is easily adaptable to carburetor-type linkages (with a rod rotating within a fixture on the manifold).  These bypass most shaft alignment issues. 
Tools you will need:
  1. Carpenter’s Level/Square or a Metal Straight Edge Ruler
  2.  Die Grinder with thin Cut-off Wheel or Hack Saw
  3. Grinder or File
  4. Allen Wrenches a good set of Bondus end helps
  5. Permanent Marker  
Step 1 - Check Alignment

First, using a Straight Edge placed across the top of the ITB Bases make sure they are aligned perfect across the top of the bases after being bolted to the manifold. Place the rule along the bore edge or bolt holes to verify alignment.  This will insure smooth shaft operation!    

    

The manifold above was a little off when we bolted the base plates “In Alignment” to it so we had to drill the Manifold Stud Threads out to allow the bases to be aligned properly!    

Step 2 - Cut Shafts

Our throttle shafts are made to bolt in to the longer spaced manifolds, such as IDA.  If your bore spacing is less than 120mm, you'll need to cut the shaft to length.  To do this, first bolt the Left ITB in a Pair of ITB’s to the Base Plate and secure a Coupling to the shaft, placing the ITB below, but squarely over it’s mounting holes.  Mark the shaft to be cut off. You don’t want the Shafts to touch one another in the center of the coupling, as this will defeat the purpose and flex of the Coupling itself.  Use a hacksaw to cut 1/3 of the way through the shaft and let it cool for a minute. There are Silicone Vacuum Seals behind the Bearings that you do not want to over heat!  

Step 3 - Cut TPS side of shaft if needed.

On DCOE/IDF or 90mm Bore Spacing the TPS end of the shaft will need to have 3mm removed to give extra clearance for the couplings. The 2 ITB’s below show the difference (see the top of picture).  This was achieved with a die grinder being careful not to cut it all at once! Again, cut 1/3 of the way through and let coo for a minute.    

Next, round the edge of the shaft slightly to remove any burrs that may be present after the shaft is cut.  A file, Dremel tool, or die grinder will work fine. 

Assembled ITB’s on a Datsun Z Car Manifold!  

See also ITB Installation Overview