I started to put another of my Craigslist 215 Buick piles together. This particular engine had been sleeved to increase the bore to 3.75" and had a Buick 300 crank installed which increased the volume to over 3oo inches. I needed a small four barrel carburetor so I picked up the Holley Economieser(sp). It is a spread bore carb with the float between the venturis. The stock manifold is a square bore and was probably a Rochester. The adapter has to have splayed ports so lost foam was the ideal method to cast the piece. I started by making patterns of the two different configurations the located them with pins on both faces of the foam blank. A Dremel bit was used to connect the ports to either face and the sprue hot glued at an angle in one corner. Since I had to machine both faces,I did not bother with any coating. Lots of vibration when filling the flask and I topped it with my typical soup can. I pulled the crucible at 1300 degrees, scraped off the minimal dross and poured. When the sprue had cooled to about 700 degrees I tipped the casting out and quenched it. I bead blasted it to eliminate bringing any sand to the mill. That is one of the advantages of coating since it comes off in the quench. I machined both faces, cleaned up the edges and detailed the bores to clear the butterflies then drilled the mounting holes. I missed the port match slightly but it should be a runner and a new one is only a couple hours if I need it.
It's sure nice to be able to put metal where you want it, not to mention the cost savings of recycling castings versus buying plate. Best, Kelly
Yes. I was contemplating my bore mismatch and it is a result of the facing operation. When the pattern is carved they need to be offset from their final orientation.
