Cummins blue smoke issues

[Harry Newman]

Over the past two years I have rebuilt or replaced both turbo’s on my motors do to lack of power (1990 boat & motors, 2,300 hours) My mechanic and I just finished rebuilding which included replacing the exhaust housing, 1/8″ plus gap between turbine fins and housing. Mechanic had to leave so I finished reinstalling the heat exchanger, reconnecting hoses and filling the coolant. Then I took the boat for a three and half hour run. It ran okay, at least so I thought. When I got to where I was going I found that the engine was running very rough at idle and now putting out blue smoke, I fear that this is a very bad sign. I will note that when I was filling the coolant one of the jugs that I used was old and a piece of the fibrous gasket went into the coolant tank. Being in a hurry and with no easy way to remove it I decided to chance it. My mechanic say that it should not be an issue but I am concerned that it might have lodged itself in the block causing a cylinder to overheat… Granted I am no mechanic but the blue smoke is telling me something bad.

Topic

[Harry Newman]

Turbo

Thanks Tony, I see and understand. 1st off, I am not a mechanic, just a boat owner who likes to know how to maintain it, diagnose issues and fix things as needed. As to the salt water getting to the turbo, I’m not sure how to change it though. There is very little room for adjusting the exhaust system. I will give the matter some thought and talk with other mechanics. On Monday I figured out that one of the injectors failed. Made sure that cylinder was visibly ok than swapped the injector with another cylinder to make sure that it was that was it. It was. Thank goodness.

[Tony Athens]

“I figure normal condensation and age has something to do with it as well.”

This is a 100% erroneous statement that seems embedded in the minds of many including “supposedly” experiences mechanics.

Read this a few more times:

What a Marine Diesel Turbo should look like when Inspected

Tony

[Philip]

Take your exhaust elbow off and post some pictures of the exhaust outlet if the turbo showing the fan blades in focus.

[Harry Newman]

Exhaust elbow

I actually did read the article. It was very good. My exhaust elbow and turbo is original to the boat which makes it 30 years old now. 2500 hours on it. I qind I’d figured that is just normal wear in a salt water environment. Basically the boat sits for 5 months a year. I figure normal condensation and age gas something to do with it as well.

[Philip]

Look at you exhaust elbow. Then do some reading on this site about SAFE exhaust design and you will solve your long term issues.

Phil

[Harry Newman]

New Turbo and blue smoke

I didn’t take a photo of the new exhaust housing with turbine set it. Visually the distance between the new housing and fins were roughly a millimeter. Last year I had to replace the heat exchanger, that was a job in itself. Off the shelf was 1/4″ too long and I ended up have to have it custom made.

[Harry Newman]

Images attached. New and old.

[Tony Athens]

1/8″ gap in the exhaust housing outside the blade tips? Have to changes the exhaust design since you installed new turbos? If not, you have , or are going to have soon enough, bigger problems than “blue smoke”..

Better post pics ASAP of your engine installations showing all including the exhaust set ups you have.

Tony

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Harry Newman

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