so I bought this C1C last summer. The C1C is an angle valve 200hp engine that was on the Arrow among others, and it's setup for aft-facing induction. I bought the engine knowing that this would need to be done, and last night I got off my duff and got it done
I did the machine work on my Bridgeport clone 9x42 mill.
First thing I did was bolt a 246 block to the table and indicate it in parallel to X travel
Next, I set the sump on another 246 block placed under the existing aft servo mount pad and clamped it down. This way, the aft servo pad is parallel to the table. This way, since the surface that I cut will be parallel to the table surface, this ensures that the new servo mount surface will be parallel to the table. Also, I made sure that the sump flange (where it bolts to the case) was flat on the rear block that I previously bolted down. This insures that the new servo pad is also square to the case flange.
Then, I surfaced the pad with a 3/4" endmill
Finally, I drilled and tapped the stud holes, and bored the induction hole. To bore the hole, I started by drilling it in steps up to an inch, then I used a boring head to enlarge it about 0.300" at a time. I got a nasty surprise when I noticed that my boring head would only cut about 2.5" maxed out, but I discovered that I can turn the boring bar horizontally and cut much much bigger holes. The induction hole is 3.5".
I ended up cutting the pad a little higher than I wanted to, which is why it looks like I had to cut high up into the wall of the sump, and also why you can see a ridge at the bottom of the bored hole. The casting was irregular, and there wasn't enough meat on the bottom left corner. When I originally laid it out, I wasn't happy with the edge distance that I would have on that stud, so I decided to cut it up higher to make sure I'd have the edge distance. I'm going to need to take a burr to the inside of the bored hole and smooth that sharp edge for good airflow characteristics.
Another aft to fwd sump conversion
Linear Mode
