1969 Chris Craft Roamer 46 Refit: New Exhaust Risers III

I’m finally back from the funeral trip abroad. Jet lag is slowly getting better, and as the fog has been clearing it’s become apparent that the Roamer will not splash in 2016. I could rush to get it done and have it ready to bring around to my home port a month later than I planned. But I’ve learned that rushing generally doesn’t work out well, and I’d need to splash around a month past the time the yard starts packing boats in tight for the winter. The downside to leaving it in the yard for another winter is that I’ll keep having to waste several hours per day driving to the yard and back every weekend. On the upside, it’s a lot closer to my Boatamalan painter, so as I install more mahogany panels in the interior it’ll be easier for him to come out and spray the ICA clear coat. It’s not ideal, but it is what it is.

In other news, I got the dry side of the starboard exhaust riser cut and tacked together. It was a bit more challenging to work out the angles than the port side riser.

Starboard riser will have to make a loop

It would be super easy to just make a straight shot out of the turbo and point it down to the muffler inlet. But the easy road would end up potentially destroying the engine if the muffler was ever to fill with water, since gravity would cause the water to flow into the turbo and engine long before it went over the hump and out the side of the hull. To make the exhaust system inherently safe, I’ll need to have a loop coming off the turbo and going as high as possible before turning and pointing back toward the muffler opening.

X marks the spillover spot

In the pic above, there’s a 1″ x 1″ x 30″ mahogany cleat clamped to the muffler inlet, which tells me the direction the riser needs to point in at the showerhead outlet. I’ve also tied a red and white collapsible mop handle to the bottom of the U-bend that connects the muffler outlet to the exhaust port through the side of the hull. The mop handle indicates the spillover point. As long as the final turn of the dry section of tubing is above that point, even if the muffler fills with water completely, gravity will naturally force the water to drain out the exhaust rather than backing up into the turbo and engine.

Somewhere around here will be inherently safe

In the pic above, you can see the red mop handle clearly ~2″ or so below the bottom of the dry section exhaust tubing. That puts it well above the spillover point and also leaves sufficient room for the Inferno Wrap insulation I’ll use to keep the exhaust heat in the riser.

Trimming the tubing to fit the turbo flange

135° showerhead tubing + 90° turn is a bit too loopy

Final fitting before tacking

Unbolt the whole thing and line up the Sharpie marks

Let the tacking begin!

Tacked all around

Re-attach the riser, final fit, and mark the showerhead section

Remove the riser, line up the Sharpie marks, and tack all around

Tacking complete!

Loopy riser

Well above the spillover point

That wraps up Phase 1 of my riser build. They’re tacked together, with the showerhead ends pointing toward the muffler inlets. I’m still waiting for my argon diffuser to arrive, which I need to finish the welding. I’ve already got a couple of lengths of 6″ stainless tubing that I’ll use for the showerhead itself, but I also need to finish the CAD drawings for the showerhead end plates. Then I need to find somebody with a CNC cutting machine who can cut the ends per the CAD drawings.  All in due time.

Next up on our 1969 Chris Craft Roamer 46 Refit: New Coolant Hoses, Clamps, and Coolant Test

1969 Chris Craft Roamer 46 Refit: New Riser Materials

Having wasted time trying to modify new exhaust risers that simply won’t work (cost effectively) for this application, I decided to do what I’d been toying around with all along: buy some stainless tubing and mandrel-bent elbows, a new TIG welding machine, and make my own risers.

What have we here?

Verocious Motorsports stocked the items I needed, and the shipping was very quick and well done. While they’ve got 90° mandrel-bent elbows in the 4″ size I need, those only come with a 6″ radius bend. But I need short radius bends coming off of the turbos and also at the turn at the top of the engine room. Fortunately, the 120° mandrel-bends come in a 4″ radius. Perfect.

I also got one-foot sections of polished 316 stainless in straight 6″ tube that I’ll use for the showerheads. Seaboard Marine out in California (owned by Tony Athens, of boatdiesel.com fame) sells Cummins turbo flange kits at a fair price, so I picked up a couple of those, too.

All the bits and pieces

In addition to the turbo flange and the curvy bits and pieces on the blanket, I also picked up a 5-foot stick of 4″ tube, a 5-foot stick of 2-3/8″ tube, and two 4-foot sticks of 1-1/2″ tube. The 4″ tube is for the exhaust system, the other two are for the fuel tank inlets, which originally were made up of Schedule 40 galvanized pipe and lengths of hose. The stainless tubing will save 100 pounds off the stern over the galvanized pipe and I’ll  fit it a lot tighter to the hull and frame than the original-style hose.

More fancy bits for the fuel inlet tubing

I got the 2-1/2″ to 1-1/2″ reducers because the original fuel inlets are beautiful chromed bronze, but the new aft fuel tank has 1-1/2″ inlets. The 45° and 90° elbows will help get all the bends right.

The OE 2-3/8″ bronze fuel inlet and the new stainless

I’ll cut the original fuel inlet bronze pipe in half–it doesn’t need to stick into the aft stateroom that far. A short hose will connect the bronze pipe to the 2-3/8″ stainless tubing, which will drop down a couple of feet  along the transom on each side, then transition to the reducer. From there, the straight 1-1/2″ pipe will drop down to the 45° elbow, turning the pipe diagonally inboard toward the keel, where the tank is (but still running tight along the transom frames). Straight pipe will then run down to the 90° elbow, where it makes the final turn toward the fuel tank inlet. One final short length of straight tubing will get within a couple inches of the tank inlet, with a short section of hose connecting the two.

The 2-3/8″ stainless pipe is an odd size, and I don’t need anywhere near 5-feet for this fuel inlet. But, I’ll use the scraps to practice with the new AHP AlphaTIG 200X welder that’s on its way from the factory. I highly recommend Tiger Sales (tigersalesco@gmail.com ) if you decide look into buying one of these. You might be able to find the machine for a bit less, but Tiger’s pre- and post-sale support is second to none. Reports are that it’s a fine welding machine for a hobbyist like me. Time will tell. It will reportedly arrive in early March, so I have until then to cut and fit all of the stainless pieces. In the meantime, there’s plenty more that has to happen if we’re going to splash later this year.

Next up in our 1969 Chris Craft Roamer 46 Refit: Turbocators!