Porting and Polishing the Throttle Body

throttle body before porting and polishing

Throttle Body Before porting and polishing

Porting and Polishing the Throttle Body was a bit of a mystery for me.  I was able to find bits and pieces of the process on YouTube, but no video (I found) showed the entire process from start to finish.  As with all my other videos, I don’t intend for this to be a “how to” video, just more of a “this is how I did it” video.  I hope that between the video and any comments I might get on YouTube, it might help someone else out.

I broke down the porting and polishing process into several phases.  First degreasing, second porting, then sanding, then polishing.

With degreasing, I started with brake cleaner, but found it hard and frustrating to get into all the nooks and crannies of the throttle body.  After removing the sensors, I sprayed the whole thing with Easy Off oven cleaner and let it sit in the hot sun for about 20 minutes. Then I broke out the old fashion wire brushes and went to work on scrubbing.  The result was a dull, non-reflective piece of aluminum, but fairly clean.

Next, I moved on and continued to clean it up with some brass brushes that I affixed to my drill press (and moved the throttle body around the drill press).  I started out with a dime sized brush and then went with smaller brushes for the hard to reach places.

porting and polishing throttle body

Throttle Body After porting and polishing

Next came porting.  I started with the 2 big bits you see in the video, and then moved on to much smaller bits based on what I was trying to port.  The kit came from eBay and was fairly cheap.  The 2 big bits were from Lowe’s and were a couple bucks a piece.

I grinded and grinded away, trying to get rid of the big bump that caused the air to miss almost a centimeter of the throttle plate.  My goal was to make that bump flush so the air would utilize the entire plate from edge to edge.  There are also two ports on my throttle body for the 2 sensors.  I also attempted to file those down and make them smoother.  I went overboard and put two holes through the wall of the throttle body.

At this point, I decided the throttle body was junk, but continued on with the project solely for the purposes of learning.  Also, because my engine is STILL at the machine shop and I was bored.  You have to be either extremely bored, or just plain crazy to port and polish.  It takes many, many hours.

Next came sanding.  I got a kit from Jegs with 60, 80, and 120 grit sandpaper.  I guess these are called barrel sanders, but I’m not 100% sure.  If you have read any other article on this blog, you know I am a complete noob, and I make no secret about it, and most of the time, I don’t know what stuff is called.  Anyway, I used the kit (again using the drill press) and went through the sanding process from 60 to 80 to 120 grit.

Next phase was harder.  I used old fashion wet/dry sandpaper and took the throttle body through 400, 600, 800, 1200.  This is where I got kinda sloppy and stopped worrying about the small cracks and crevices.  In the back of my mind, I didn’t even know if the throttle body would be savable with the 2 holes I put in it.  More on that later.

Polishing – I got the cotton polishing bits you see in the video (again on eBay) and proceeded to polish starting with the black bar, moving on to the brown bar, then the white bar.  After that, I polished with a coat of Mother’s Aluminum polish and was done.  NOT!

I took the throttle body to a friend who knows how to weld, and he said that trying to weld aluminum would just make the holes bigger.  He was not the one who recommended the Alumiweld (that I ultimately used), I found Alumiweld on my own on YouTube.  He recommended just getting a new throttle body.

When I found the Alumiweld solution online, I had to give it a try, so I ordered some for Harbor Freight.  You see the final glob of aluminum I placed on the back side of the throttle body in the video.

Then it was back to sanding.  40/60/80/120, then a break, then 200/400/800/1200.  Then back to polishing.  Black bar, brown bar, white bar.  Then the final result is in the video.

I’m putting the video on YouTube in hopes to get some constructive criticism on the process I used and for thoughts on if the damn thing is even usable.  I’m not sure how much heat the throttle body is subjected to in the engine bay, and if those “welds” will even hold.  If you are reading this, feel free to comment here on the blog, or over on YouTube.  Thanks for reading.  Here’s the video!