American Tug 34 Exhaust

[Jonathan St.Mary]

Pictures of 2004 install.  I suspect the original elbow is near end of life.  Pictures attached.

Topic

[Fireisland1]

Don’t make this your Final decision, phone a friend. Why would you invest in a ‘ near exact ‘ replacement when the original was not right. This makes no sense to me. Get something built properly and forget about it.  Maybe $5k . If you ruin the engine it’s $40k and you still will need a new exhaust. 

[Tony Athens]

When you drop a valve from saltwater feeding your turbo, don’t say you were not warned.. .. It’s not the elbow, its  the LWL in relation to your turbo inlet.  Your exhaust system  lets water into your turbo when you engine is not running–It’s called gravity  

[Jonathan St.Mary]

Final decision

I bought a (nearly exact) replacement to what had been there.  I was able to avoid major rework of the area around the exhaust, which almost any redesign would have required.  I’m sure it will fail eventually.  If it does, I may go to some exotic material . . .

[Chris Rupe]

End Result

Hello Johnathan.

What was the end result and or correction to your Cummins OEM/American Tug exhaust issue.

Thank you for any info.

Chris

[Tony Athens]

Johnathan. Only ONE of the pictures tells the story as to what American Tug sold you.. An inferior designed exhaust system and was probably OK-ed by some Cummins engineer that had his head where the sun doesn’t not shine), and that design has been allowing water to back up into your turbo , but hopefully not worse…………………….At the VERY least, you need a proper riser, but possible more that than…………………. This has been going on for a long time………. Where do you go from here? Real simple, plan on redoing do the riser and have your turbo rebuilt.. That’s the absolute you are in for… Tony

[Jonathan St.Mary]

Mixing elbow definitely shot

Got the elbow off the QSB380 with a combination of PB Blaster, brute force, and ignorance. The elbow has several pinholes between the water jacket and the interior. The interior is sverely pitted at eh wet end, though the dry end seems fine.
Attached are a few photos – the really dark one is an attempt to show the pinholes, using a bright backlight in the water jacket.

Sorry about the formatting – I don’t know how to make word-wrap turn on.

[Jonathan St.Mary]

Bolt heads

I will continue trying to get things apart.  Worst case is I snap the bolt heads off.  If that happens, I’ll pull the elbow, then weld a nut in place on the stud, and keep trying.  I’ve run into this sort of thing repairing old steam locomotives – just not in such confined space.

[james]

bolt heads

Good luck on those bolt heads.  On my engines, we ended up having to take the Turbo’s off with the elbows and cut the heads off.  I tried for a solid week with every penetrating oil I could find.

I currently back those bolts out about 4 times a year just to try and prevent future problems.  To get them started, I welded a 6 point 10m box wrench to an old adjustable wrench, giving me a lever arm of about a foot and a half.  Really makes a big difference.

[Tony Athens]

Jonathan,

 

Considering what you are dealing with, don’t you think it would be prudent to remove the wet mixer from the engine for an internal peek of the exhaust outlet side of the turbo? I suspect your issue goes deeper than you think..

Tony

 

 

Tony

[Jonathan St.Mary]

AT-34 Exhaust – inspection

I’m going to remove the hump hose, and see if I can clean things up enough with the elbow in place to see what the condition is.  There isn’t much room, but maybe with bright lights and mirrors . . .  Right now, the bolts fixing the elbow in place are holding tenaciously.  Penetrating oil will be applied occasionally over the next few weeks, as I find time to get to the boat.  If that doesn’t work, I’ll try heat on the assembly to try to avoid snapping off the bolt heads. 

[Jonathan St.Mary]

AT-34 Exhaust – further info

Pretty much the whole engine is below the waterline.  In fact, the waterline is about the same level as the axis of the turbo.  The outlet from the turbo turns 90 degrees and points straight aft, at a slight down slope of about 6 inches per foot.  Right after the hump hose, another elbow connects the exhaust to the side of the muffler.  After whatever happens inside the muffler, the exhaust comes out of the top of the muffler, and up and over the last arch before exiting under the boat.  The waterline is about 13″ below the bottom of the arch.  Picture attached.  You can see the mixing elbow on the right edge, the muffler, and the final pipe coming out of the top of the muffler.

[David Marchand]

And do you have the recommended 12″ or greater from the waterline to the bottom of the dry part of the elbow/mixer (the spillover point). It looks like you have room to add height if you don’t have 12″.

David

[Rob Schepis]

Inside a 12 Yr Old OEM Mixer

And this was a brackish water boat since day one…  I add an exterior shot just to prove you cannot “judge a book by it’s cover”….

[Rob Schepis]

Photo Re-Orientation and Further Inspection

I deleted 3 of your pics and re-posted here with proper orientation which is helpful for getting a better feel of what you have.  Are you planning on taking the elbow apart for a turbo inspection and a cleaning and interior inspection of the elbow?  I pulled my OEM mixer in 2014 for a complete exhaust redo including Seaboard dry risers, the OEM mixer was self draining but still not pretty inside.  I’ll post some pics…

[Author]

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