Bluish grey exhaust smoke

[Boatsb]

one of our members here rebuilt heads for those or ones like them. What a machining job it was as I understand parts are not available and had to be made for them.

Word is there are only a few of those marine lambos in existance. Id be easy on them too if they were mine. probably $4k a hole to rebuild.

 

[Triskele]

Black smoke is non burnt fuel (either too much fuel, or not enough air), white smoke is generally steam and bluish smoke is burning oil, one possible cause is leaky blower seals. to check; remove intake from blower, start engine and shine a light across the top of blower, if your see a mist then you have a leak (also, if the rotors of the blower are wet, this would indicate oil coming in with your air charge). Be careful not to allow anything to fall into the blower.

good luck,

Pete

Hello Pete...

Have given a bit more thought to my blue smoking problem and am leaning more towards the idea that it is either a blower seal or oil leaking in from the turbo. To check a leaky blower seal you suggested removing the intake from the blower and check for an oil mist. My boat has an Airesearch turbocharger. The blower intake is connected to a heat exchanger which cools the air from the turbo (I guess) and then the air from the turbo is fed into the blower? I have attached some photos. Was your advice for a naturally aspirated or turbocharged engine? I'm presuming both, but then the question becomes, do I have to remove the heat exchanger to look inside the blower or is there another way?

Okay, also, the starboard turbo (its the starboard engine that is blowing the blue smoke) seems to be more oily than the port turbo leading me to believe that oil may be getting directed to the blower from the turbo. Could the turbo be throwing off oil into the blower? If so, how can I check this out. What should I be looking for. Presuming that there is leaking oil, it seems most trouble shooting guides point to seals. Is there a way to know or test if a seal is bad? How does one know if the culprit is actually the seal or something else short of replacing it? From the photos you can see some oil on the rubber pieces connecting the air tube from the blower to the heat exchanger. In comparison, the port connections are clean and dry.

Sorry attached pics aren't very revealing, but meant to show oil dripping from turbo air intake filter (which I'm told is usually normal) and oil around air tube. Other photo is of heat exchanger in front of blower. Will I need to remove this to get to blower intake? Please feel free to share any thoughts on the matter. If your experience and advice is only relevant to naturals, please indicate that as well. Thanks.

 

[osprey]

Hi I have just re-read your original post as well as your last one. As for my suggestion to run the engine with the blower intake removed so as to look for a oil mist, you are correct it is very difficult to do with a turbo engine. But you can still look at the blower lobes with the engine off and if one end is wet this would suggest a leaking oil seal in the the blower. But first, you suggested there may be oil coming from the turbo, yes the seal in the turbo is a very likely culprit, remove the rubber boot going from the turbo to the intercooler, if its wet with oil the turbo is most likely leaking. also look at the compressor side of the turbo (air intake) not sure what you have for inlet filter, but if you use an airsep or other system that helps the rocker cover vent, the oil drain could be blocked and you may be pulling oil from your head cover. Another note, you mentioned that the mech set up the rack, did he set the exhaust vaves before setting the injectors? This would not cause oil burn, but may have more to do with your engine hunting.

Good luck, Pete

 

[osprey]

Further, on some engines, on the right hand injector control tube there is a throttle delay mechanism, which is a piston that prevents the rack moving too quickly to prevent engine smoking when reving up (allows the turbo to keep up with air demand. The ajustment and timing of the injectors is critical. if you have a thottle delay mechanism, it needs to function correctly or it will causes all sorts of performance issues. will the engine make max rpm under load?

Pete

 

[Triskele]

Further, on some engines, on the right hand injector control tube there is a throttle delay mechanism, which is a piston that prevents the rack moving too quickly to prevent engine smoking when reving up (allows the turbo to keep up with air demand. The ajustment and timing of the injectors is critical. if you have a thottle delay mechanism, it needs to function correctly or it will causes all sorts of performance issues. will the engine make max rpm under load?

Pete

Thanks. I'll take a look as well. Am not familiar with the right hand injector control tube or the throttle delay mechanism. Will need to do a bit of research there. Others on this thread have pointed to piston ring and exhaust valves as the potential problem. I'm not sure I would agree. Seems that black smoke would be my problem with those issues. Not blue. To me, blue smoke is more a symptom of oil leaks in the air that is provided by the blower to scavenge exhaust gases after the power stroke. A bent valve or stuck ring would more than likely cause oil to mix with cumbustion gases causing black smoke. As well, black smoke is attributed to incomplete fuel burn (fuel that would escape throught a pourly seating or partially closing exhaust valve. My problem is blue smoke, not black. That's why I tend to go with your theory? What do you think?

 

[osprey]

worn rings could allow oil to get above the piston and cause blue smoke. But as you said in the first post, you did not have this problem before the oil change and rack ajustment, check that turbo.

Pete

 

[Triskele]

12-71Ns with a few million neglected hours on a 1974 58TC. After being under water a few days
(sunk) they fired right up. 1500 mile trip from NOLA to Chicago at 1400 turns and 11 mph, used
4 or 5 qts of oil per engine. Port engine has a leaking injector producing slight sheen on the water...


https://www.youtube.com/watch?v=ifkfGV7L0CI


After a 2 hour run I spooled 'em up to about 2400 (by the tachs with some left!!) and they get
clean...

https://www.youtube.com/watch?v=_gXjN60SLwg

https://www.youtube.com/watch?v=jCyYi3UQaEY

https://www.youtube.com/watch?v=UNFGwPgbEOE

Like Jabril says, "Drive it like ya stole it..."

Can you explain to me what you mean by you "spooled" the engines up and why you do this? I ask because a mechanic who worked on my engines recommended that before shutting down my boat after being out on the water that I should open the engines up to full throttle before backing them off and low rpm them into the marina. What is the purpose of doing this and when should it be done. Today I had the boat out and both engines were running quite well. Before going into the marina I ran them up to full rpm for about five minutes (2300 rpm on the port and 2100 rpm on the starboard). When I cut them back to idle the oil pressure dropped to near zero in both engines. As I idled into the marina the starboard engine was "hunting" the whole way and idled at around 375 rpm (normally it idles around 500 rpm). When initially starting the starboard engine, it "hunts", but settles in to steady idle after less than a minute. I know that hunting is related to tuning, but this seemed to be more than a tuning issue. Anyway, can you explain the purpose of spooling the engines and how it should be done correctly?