I decided to spend some time working on the intake manifold and throttle body.  Along with everything else, these parts will be sanded smooth and painted.  I haven't decided on the final color of these, but that won't change the prep required.

Here is the throttle body before getting started.  That raised text must go!

Bocar? Nope.

In addition to smoothing the parts, I'm working on the joint between the throttle body and upper intake manifold. First off, the throttle body is from an OBDI MK3 Jetta (1994) and the manifold is from a MK4 Jetta (2002), so the castings don't match.  And even if they 'matched,' they would not match exactly.  I plan on sanding them while bolted together to form a perfect set.

Another thing that must be considered is the gasket.  Unless I match all three pieces together (throttle body, gasket, and intake manifold), they will never align perfectly.  In order to eliminate one variable, I decided to skip the gasket and retrofit an o-ring seal to the throttle body.

Here is the gasket face of the throttle body, before modification.

The first step was to make a fixture so I can turn the throttle body in my lathe.  It's difficult to grip since none of the surfaces are perfectly round or square, so I decided to bolt it.

The fixture mounted in my lathe and turned true to the axis of rotation

The first step was to mount the throttle body and turn the outside face, which was originally just a rough casting.

After flipping it around and bolting it to the same fixture, I added a face groove for an o-ring.

Look at this tool clearance!!  I had to clock the bolts exactly right so they didn't hit the grooving tool.

Done. Now it will seal completely without a gasket.

I also noticed this ugly barb fitting, which I decided to remove.  The casting was just the right size for an SAE -4 O-Ring boss fitting, so I cut off the barb and added the features for a proper fitting.

With the barb removed, I found the center of the hole to prepare for the next step.

Done.  This will be much more clean than an ugly barb fitting and allows me to use the same AN fittings and hose I'm using in the rest of the engine bay.

Another project I had left unfinished a few years back was the coupling between the throttle body and intake tube. Here you can see it wasn't symmetric - the throttle body had a round bead and the intake tube was just smooth.  I didn't want to add a fancy coupling, like a Wiggins clamshell clamp, because it doesn't quite have the right look.

Fast forward to modern times, and I have a Kramer bead roller!  I bought this for a Fort Pitt Classic Cars project a little while back, and it's the perfect tool for the job!

I'm going to trim the length of my intake tube to make it even more symmetric, but generally I'm happy with it!  The outer diameters are within 0.010" or so when they're perfectly aligned.

I also found this K&N coupling for 2-3/4" tubing, which didn't exist when I started this portion of the project.  I think it will look just right in the engine bay - just the right mix of custom and OEM style and a nice shade of satin black.

Back to the matching of the throttle body and upper intake manifold.  This simply won't do:

I still have a lot of work to do, but it's already looking much better!