Blast Tubes Fabrication
Moderators: GAHorn, Karl Towle, Bruce Fenstermacher
Blast Tubes Fabrication
I’ve read with great interest about the importance of correct positioning of the blast tubes that reduce engine oil temperature. I’ve never been satisfied with the high oil temperature in my ’52 170B with a 300A, with “D†accessory case and with oil filter adapter. The right blast tube is positioned correctly in the middle of the filter adapter, but the left one was positioned in the general area of the back of the accessory case. I manipulated the left tube to point at the middle of the oil filter adapter and this effort reduced the oil temperature by 30-40 degrees. I wasn’t satisfied with the tube positioned being too close to the primer line and it needed to be extended approximately 1-2 inches aft for a proper fit. This made me wonder where one could obtain 1†aluminum tubing suitable for fabricating new tubes, especially with the required 90-degree bend. Then I remembered those old 1960-70s folding aluminum lawn chairs with the web bottoms that ‘Bubba†had fallen through. I had a couple that had the front leg that came down from one armrest to the ground, crossed over and went back up to the other armrest. I was in luck; they were 1†diameter and had the 90-degree bend and the same material as the original blast tubes. You have enough tubing to fabricate two tubes. Cut the leg in the middle of the section that sat on the ground. Fabricate two 3†circular aluminum mounting plates with a 1†center hole. After correctly measuring your application, place one mounting plate on the tube. If you don’t have access to aluminum welding, you can make ¼†long slices spaced ever ¼†on the front edge of the tube, bend those out to make a flange, move the mounting plate against the flange, use the other mounting plate to sandwich the flange. You may want to use metal glue or J&B Weld between the two plates. Drill the three mounting holes. You now have new inexpensive blast tubes that are “owner manufacturedâ€.