Just bought first diesel (Cummins) boat, blue smoke

[Steve Barrett]

Hi guys, new member and first time poster here. First I want to say thank you for this awesome web site. Just purchased my first diesel boat, a very clean 2002 410 Sea Ray Express powered by twin Cummins 6CTA8.3-M3 450 Diamonds (Serial numbers 46177147 and 46176773, CPL 8089). Engines only have 750 hours on them but 15 years of marine age. Prior maintenance records were minimal when I got the boat so I am in the process of establishing new baseline of engines. Used photo tach today and confirmed accuracy of my dash tachs. Unfortunately the dash tachs are pretty accurate and I need to get some prop work done. Here are the numbers.

Ran boat to get engines to operating temperature, both engines stay right at 160 degrees, Dash tach vs. (Photo tach) readings:

Port engine:
Idle RPM in neutral: 650 (630)
Idle RPM in gear: 600 (560)
WOT NO load RPM: 3100 (2980)
WOT at cruise: 2500 (2550)

Starboard engine:
Idle RPM in neutral: 650 (620)
Idle RPM in gear: 600 (575)
WOT NO load RPM: 3000 (2968)
WOT at cruise: 2500 (2540)

Only other issue so far is both engines are producing blue exhaust smoke. I believe this usually means engines are burning some oil. It is not coming from the crankcase, been keeping eye on oil level and it has been stable. Could it be the AirSeps need to be cleaned?

Aftercoolers: Last serviced, ???? This is number one on my winter to do list
Heat exchangers serviced in spring 2017
As you can tell from the pictures, I already have some exhaust elbow issues. Don’t think I will be able to get the turbo off without snapping some of those rusted bolts off.

Future projects:
Install redundant engine alarms:
205F temperature switch
Low Engine Oil Pressure
Raw water failure alarm
Low Gear Oil Pressure
Valve adjustment
A visual inspection of both sides of the turbo
Replace Transmission oil coolers
Install EGT (exhaust gas temperature) gauge
Install Turbo boost gauge
Upgrade to SeaMax pumps

Topic

[Steve Barrett]

New elbows it is

Thanks guys. That is why I came to this site, to keep the newbies like me from making a major mistake. I will have to print some more $ and get the new elbows made. Would anyone have any recommendations on where to get this done on the east coast, Annapolis, MD?

Tony, I know you guys can handle this job, any idea on how much you would charge for 2 custom elbows?

Thanks in advance,
Steve

[Tony Athens]

Steve,

It’s hard for me to believe you’d even consider re-installing your old exhaust mixers with your new turbos..

Not much else for me to offer other than, IMO, you are making a major error in judgement.. If you need to move your boat, have it towed.

Tony

[firehoser75]

Exhaust Elbows

Hi Steve,
I agree with Dan!!!
I replaced my exhaust elbow this year due to an exhaust hose overheat issue. I only discovered this problem because I had installed an exhaust hose heat alarm. Send at least one of your elbows to the radiator shop for cleaning. That is how I discovered that mine was corroded through. It did not look anywhere near as bad as yours and my turbo was luckily still OK. If you continue to run the boat with these old elbows and new turbos, you risk ruining the new turbos (or at least damaging them), but potentially even worse, allowing salt water into the engine. In the worst case, that could lead to major engine issues costing mega dollars!
I had a custom “dry” elbow (with water injection down near the hose connection) built to reduce the potential future problem of salt water intrusion. Yes new elbows are not cheap, but a new or rebuilt engine is way more. My custom elbow cost about the same as the Cummins original elbow. Photo of new elbow attached, but upside down for some reason. At least if you do all this now, you will have a good starting point for moving forward.
Good luck with your decision,
Tom Easterbrook

[Dan]

‘Exhaust redesign will have to wait until this coming winter”

If this where my boat the priority would be the exhaust issue,looking at the pics it doesn’t look to be a big issue to set it up correctly,

[Steve Barrett]

New turbos finally arrived

Finally got new turbos from Cummins. Wow, what a difference. My old turbos really were in bad shape.
Exhaust redesign will have to wait until this coming winter. Already spent to many $ this year. I boat in the upper Chesapeake Bay so the water is not that salty. I will religiously flush system and drain exhaust elbow this season to minimize any damage to the new turbos.

So here is my status and question. All components in the seawater circuit serviced, pressure tested and reinstalled. Will install new turbos and exhaust elbows this week and refresh the engine coolant. Question is, boat is currently in the water and winterized. Can I run the engines to get the air out of the freshwater cooling system and also travel approximately 100 yards to get hauled out without using the seawater cooling? Seacocks are closed and impellers are removed. Need haul out to get props off to be redone and new transducers installed.

[Rob Schepis]

Great….15 years of marine age and they are serviceable tells you 1 or more of the following apply:

a) prior owner(s) proactive maintenance schedule w/ proper methods
b) slipped in brackish/fresh waters
c) religiously fresh water flushed

They could also be newer than the engines themselves but that is neither here nor there as all that matters now is going forward. Hard to tell but maybe in that second picture I am seeing green grease around the core end and anti-seize in the threaded holes for the cap bolts..

If you’ve jumped right into this as a new owner I’m sure you have read all of the articles here about the servicing and the thick vs. thin o-rings.

That should be just condensation puke settled around the base of the core but do pressure test the core itself (after cleaning but before assembly) to verify no seawater seepage and then pressure test the assembly.

[Steve Barrett]

How about some good news!

Thank you everybody for the great information and helping me through this for my first time. I will start reading the articles on exhaust redesign and am working with local Cummins dealer on getting some new turbos. Now for the good news. Took apart one of the aftercoolers tonight and was shocked at how easy it came apart and how clean it was. Already have the Seaboard rebuild kit to clean it up and put it back together (as per Tony’s protocol of course).
Happy New Year

[Tony Athens]

Your exhaust system is “feeding the engine” SALT water and it’s been doing it for years..

From the looks of the housing, they are not rebuild-able……..

#1——You need to redesign the exhaust risers–Luckily you have the room to do it right and there are dozens of example of what would work in the exhaust articles on this web site

2) Get new turbos

3) Prop down at least 2″ of pitch so your engines spin up easy to OVER an accurate 2700 RPM

4) Your oil consumption / smoke is probably from the turbos being done.

Tony

[Rob Schepis]

As the turbo housing rusts away the wall to the coolant jacket thins out. That rust looks deep.

[Philip]

The wetness is salt water eating your turbo.

Although the elbow looks ok, it’s the design and install of the exhaust not the elbow itself. Even with a 100% perfect brand new elbow the way it’s installed/designed is what is causing your issue. It looks from the picture of you cutting the bolts that there is lots of room above the turbo to take advantage of designing a new exhaust with a hump and injecting water on the downhill side of the hump which will fix your issue.

Time to get that turbo off and rebuilt. But without redesigning the exhaust install you will face the same issues in time.

When installing the elbows to the turbo use new bolt/washers and use plenty of hi temp anti seize. It’s even worth it to pull one bolt at a time and reapply the anti seize on a yearly basis just so you don’t have to deal with cutting the bolts in the future – that’s a real pain.

Glad to see your getting after it in a systematic way. You will be happy when all the hard work is done and your mind is at ease knowing all is safe as you motor. And thanks for posting pictures so we can all learn as you go through the process!

[Steve Barrett]

Turbo issues????

Many issues to discus but want to start with the most serious first. Pulled the exhaust elbows today, we had to cut off the bolt heads because they were rusted so bad. Honestly I have no idea what to look for, but to me the elbows look pretty good. They were dry and had some carbon build up. The turbos on the other hand, they look bad. Very wet and not sure if its rust or carbon build up on the inside. It looks like they are rusting from the inside out. Could the wetness be the engine coolant leaking in to the turbo?

[james]

I've seen that exhaust situation before

A friend of mine has a searay 44 with twin cummins, his exhaust flow looks to be similar to yours, essentially asking water to run uphill. Suggest you get that fixed in a big hurry. I would suggest you do everything in your power to get the exhaust separated from the Turbo. Mine is the voice of experience, when you have to take them off together, it is a very heavy job. Good luck.

[Rob Schepis]

Doomed to Fail

Cale,

Basically the “doomed to fail” category is for those wet (seawater jacketed) risers that are either too flat to fully drain or are oriented upward so that they hold water after the engine is shut down. Some of these setups do provide safe height to the exhaust but they are guaranteed NOT to last because the seawater corrodes them internally causing them to leak seawater back into the turbo, exhaust manifold, cylinder, etc etc.

Here’s a good link:

Marine Exhaust Risers that are Doomed to Fail

[Philip]

Have you read…

Everything you Need to Know About Marine Exhaust Systems

What a Marine Diesel Turbo should look like when Inspected

Cummins Marine Aftercooler Maintenance

[cale domek]

Hi guys, I have read and reread all I can on cummins motors. Would you guys mind pointing out the specifics in regards to the doomed exhaust system? I have a friend who is searching for one of these 410 express’s and any info I can pass along is helpful. Thanks for all the knowledge in advance…

cale

[Philip]

Yes…. I’m my response I failed to state that the exhaust is “doomed to fail” at some point in the future if not beginning already. When you can it would be worth pulling the exhaust elbow and posting some pictures of the turbo insides as it will telll a story….

[Jason Leslie]

Wow, from the looks of the paint on those engines, you have to appreciate those Cummins motors. For the past 15 years and 750hr of use they have been saying I’m Giving You All I’ve Got Captain. But the previous owner/operator didn’t care to unload those engines and give them a breath of cool air, and easier work load. Glad you care and are willing to make it right. Seriously, they have been through a lot and have survived a crappy exhaust install as well. Correct the obvious and they will be so happy with their new owner they might return the favor with many more years of happy trouble free service.

[Philip]

What you already know

1. Overpropped
2. Aftercoolers need proper service and pressure testing

What i see
1. Your port intake heater had something going on with it given the paint discoloration. I would investigate that and consider removal from both sides.

Get yourself propped correctly and aftercoolers serviced and then see what the blue smoke does.

[Fireisland1]

I’m no expert but it sure looks like some real hot air going into those inter coolers. Maybe run hard and not proped right?

[Author]

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