[Antonio micula]

Hi recently i have noticed oil coming out on blowby ( pls check attached photo).
There is about 4 oz after 20 hours of engine run.
Any recomendation?

[Antonio micula]

Tony

Finally we have adressed last problem which is causing black smoke.

Last week after test run with bypassed muffler i have noticed that black smoke is minimized , it is remained only at 2300 – 2500 rpm but only a little bit and i would adress that to boat hull type because that is when boat is pushing biggest amount of sea.

If i compare boost with and without muffler i can see that i can get more boost at lower rpm with less black smoke.

And now I come to another issue and that is new muffler installation and i would need more advice about that.

I have attached drawing to better explain which are mine limitations , and the biggest is not enough space between water line and deck where i have to install new muffler.

I will make new riser where we will use all available height and that will be about 14″.

1. Original Yanmar wet exhaust is 5″ , can i use same size for all system or i have to go to 6″ or more in order to reduce back pressure? Manufacture suggest 6″or even more for 370 hp.

2.Since i have only 10″ above LWL , which type of mufller i have to use (in-line or lift ) , to get less back pressure and less noise?

Thank you

[Antonio micula]

Tony

Please find attached picture where you can see bolt on the exhaust elbow where test probe was connected

[Antonio micula]

Tony

– Probe was installed on the exhaust elbow test port

– He was using digital gauge..i am not sure which brand

May I ask (just for my understanding) please :

– if boost is reaching good 35 psi for the 3400 rpm does this still means that back pressure have negative effect on engine?

– at about 2500-2600 rpm when smoke is worst , back pressure is about 70 inH2O ( still within limit) , does this means back pressure is not problem at this rpm?

– could I do a simple test by bypassing muffler , just temporary for testing to see does smoke goes away?

[Antonio micula]

Hi Guys

– Finally i did back pressure measurement : at 2500 rpm – 70 inH2O
at 3100 rpm – 118 inH2O

– Just reminder that boost pressure at 2700 rpm is 15 psi and at 3400 rpm is 30 psi(full scale).

– Yanmar mechanic who did measurement said that on my turbo there is NO waste gate .

– I can reach max 3400 rpm

[Antonio micula]

– it might be connected with planning curve…my boat is pure semi displacement type….but then again , how come the other boat (same as mine) with less hp(iveco 280HP) is got same max speed and it doesn’t have black smoke….that is what bugs me

1. I will be in chance to measure exhaust pressure in few weeks

2. photos attached

3. I am not sure where is it and how to check waste gate?

4. On the last test run (video posted above) i could get 3500rpm on the yanmar tachometer , this is accurate 3430 and still you can see on video there is some black smoke….on the video I am running at 2700 rpm first and than drop to 2500 rpm

[Antonio micula]

and more

[Antonio micula]

here are some photos

[Antonio micula]

Tony

It will take some time until i will be able to do a backpressure test.

Tomorow i will post some photos of exhaust system.

I hope you dont mind if i ask a few questions

1.does engine has to be loaded(running a boat) while taking a readings…..all rpm ranges?

2.if we allready did confirm that boost pressure is OK….is there anything else how backpressure can cause problems (especially black smoke)

Thank you

[Antonio micula]

1.I have personally installed boost sensor and it is installed on the dedicated place for it next to oil pressure sensor , this means that boost is measured after intercooler

2. I did measure back pressure , and it was 0 (zero) psi….i did measurement with analog pressure gauge with 6 bar scale and needle wasn’t move at all

Right now I am at work , but i will ask my friend to take some engine photos and i will post it tomorrow.

[Antonio micula]

1. yes turbo just came back from overhauling from specialized company , and exhaust is OK

2. as far as i know , mechanic took intercooler to his workshop and soak it in some liquid….I dont know more details

3. I have check rpm with special instrument and then compare with yanmar tachometer…yanmar is showing 70 rpm more….so I am deducting 70 rpm from yanmar tachometer

4. it is 3700 rpm on yanmar tachometer…if I deduct 70 rpm that is 3630 rpm

5. yes I am measuring boost pressure….at max rpm is over 2 bar(30 psi)….the max scale on the instrument is 2 bar and it is going even more….before turbo overhaul it was 2 bar straight
At 2700 rpm which i like to run most is 1 bar (14.5 psi)

[Antonio micula]

Thank you for reply

Let me try to explain because i dont want to look like i am making up stories.

I did not have prop done again but this time boat was lighter for about 350 kg or 800 lb and turbo was overhauled.

Video is done recently when boat is lighter and after turbo overhaul and there is still a smoke. Max rpm in this conditions is 3430rpm.
However i did check max rpm with loaded boat (like before when max rpm was 3330)and it went up to 3370 ,what is telling me that i get about 40 rpm after turbo overhaul.

Why i did turbo overhaul?
When i was leaving home for a work i found mechanic and told him to remove fuel pump and send it for repair. Well , when he came on boat(i was already gone) he decide that turbo is bad and that he want to try with turbo and intercooler overhaul first.
I tought OK…it can not hurt…and is cheaper…if it doesnt help we will do pump

So,when i came back home(after 1 month)….mechanic has installed back turbo and intercooler….we did test run with lighter boat…result is that i can almoast reach required rpm but smoke is still there?!!!?

What to do…what to think?

Just to mention that any mechanic i have been asked to remove fuel pump was not happy or confident about that job. Conclusion is that is not easy to find really good mechanic,at least here where i live.

And to mention….sudden stopping problem was dirty fuel problem….i have cleaned pre-filter and replace filter and no problem since…

Sorry for long post but i hope things are more clear now…

[Antonio micula]

anybody?

I have hit a wall here…what to do ?

[Antonio micula]

On the above link it is possible to see how does it look like when I am running.

Until about 35th second of video engine is running at about 2750 RPM , after that it is about 2500 RPM.

I would appreciate if i could get opinion is this colour and amount of smoke acceptable ?

[Antonio micula]

According to company that did turbocharger repair no any major faults was found.

[Antonio micula]

Yes I did say that I will post picture and I am sorry i didnt . Unfortunately nature of my job is that i travel a lot and i don’t have enough time to spend on my boat so i just let mechanic to take off turbocharger and send it for repair . I tought it can not hurt. The main thing is that this engine is used and i dont know real history so every maintenance is welcome. I forgot to mention that intercooler was cleaned as well .

Below are photos that i took at that time when i promised that i will post them , but i was dragged to something else.

[Antonio micula]

Hi all

After some time i did more test runs.

Just reminder about engine :

Turbocharger hes been sent for reparation.

We have replaced all 6 nozzles and calibrate them properly to 260 bar.

Intake and exhaust valves clearance was adjusted by service manual to 0.1 and 0,5 mm.

Engine working temperature is OK , about 70-80 degrees Celsius .

Propeller has been sent for correction and now i can reach 3430 rpm.

There is still some black smoke coming out exhaust (and black liquid), starting at 2100 rpm and the worst is at 2500 rpm.

At 2700 rpm black smoke is changing to black and white smoke (like vapor), at this time boost is about 1 bar (14.5 psi).

What I am not sure is how much black smoke is normal ? After all this work at engine , amount of black smoke is much less but it is still there , and not only when accelerating but also when running constantly (especially at 2500 rpm).

Please note that same boat as mine with 280hp Iveco engine is got same max speed (21kts) as I have with 370hp yanmar?

Attached photos are showing smoke at 2700 rpm.

[Antonio micula]

Hi

It just happend half hour ago again….It is was not shut down completely….just rmp drop down by itself….from 2600 to app 800…it took like 20 sec to rev up again……the other day happened diferent thing…I lowered down by command rpm from 2500 to app 1300 and engine shutdown byitself…..in both cases it looks fuel reduction….in fuel water separator i have noticed dirt…
Maybe I need to change diesel oil filter

[Antonio micula]

Tony

Yas i did check tach accuracy and is reading 70 rpm more…since it is reading 3400- real engine rpm is 3330.

I will post turbo photos later when i get to PC.

What do you think why engine is sometimes shuting down when i am sudenly slowing down…for example from 2000 rmp to minimmum rpm?

[Antonio micula]

Hi guys

I have update….propeller is changed as per calculation from 21 X 26 to 21 X 22.

I did get 400 rpm more and now max rpm is 3350.(unfortunately not 3450)

Black smoke is significantly less but it is still there. Black smoke is starting at 2150 until 2750 – it is less then before but you can still see it.

Lets say I am happy comparing how it was before.

However the other problem what i have experience is engine shut down when fast lowering rpm from about 2000 to minimum rpm (it happen twice).

Just reminder my boat is semi-displacement hull and it is not going easy to plane (maybe this should be taken in consideration)??….i did check turbo and no signs of rust….i did check back pressure it is almost 0 psi.

Thanks a lot for your help it means a loooot to me.

Toni

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