DATELINE: Far side of planet earth (finally getting over jet lag, just in time to return stateside and start over).
While working on the engine wiring, there were several times when the project got stalled because I didn’t have the right hardware to get ‘er done. Since I can only work on the boat on weekends, a week can go by waiting for new parts to show up so I can continue the job. There are plenty of other things to do on the boat, though, and getting the exhaust system finished is a big item on the honey-do list. I’ve got all the tubing I need. I just need to finish preparing the mufflers, then cut, tack, and weld the risers together.
In retrospect, I may have been able to save several hundreds of dollars by buying a 5-foot length of 6″ stainless tubing and cutting it to size rather than buying Centek crush sleeves at $58/ea (wholesale). Ah well…that wouldn’t be the first time I made a noob choice that cost more than it had to.
I still haven’t decided for sure how much I want to isolate the mufflers so they don’t transmit exhaust vibrations. Since they’re not solidly attached to the engines, vibration may not be a problem at all. Time will tell.
The 180° connector above the muffler allows it to be rotated and also moved in a small arc to line the inlet up with where the riser will be.
I had a problem with slightly crooked cuts on the stainless tubing I used for the fuel inlets, which took more work on the disk sander to get the mating surfaces fitting tightly. With the bigger 4-inch tubing I’m using on the exhaust, it was even more of a priority to make sure the cuts were all true. I followed online instructions for truing 4×6 metal-cutting bandsaws, and it cuts nice and straight now.
The muffler inlets are ~6″ in diameter. By clamping two 1″ x 1″ x 24″ mahogany cleats to the inside of the inlets, the distance between the two inner surfaces of the cleats is ~4″. By clamping the 4″ tubing to the other end of the cleats, I can position the mandrel-bent section while being confident that the other end is pointed directly at the center of the muffler inlet. When I weld on the showerhead, which will be made of 6″ tubing, it will be pointed right at the muffler. That’s the theory, anyway.
Note that the “spillover point” on the dry exhaust side is well above the lowest point of the 180° connector coming out of the muffler. That way, if the exhaust system fills with water it will naturally drain out the side of the hull rather than backing up into the engine. The 6″ exhaust pipe out the hull side would have to be completely full and still overflowing under substantial pressure before water can end up in the turbo. Gravity makes that pretty much impossible.
The dry side of the port exhaust riser is ready to be welded, but I’m still awaiting the delivery of some gear to purge air from inside the tube and replace it with argon. I also have to make the dry section of the starboard riser and have some parts CNC machined for the showerhead.
Next up on our 1969 Chris Craft Roamer 46 Refit: New Exhaust Risers III