# high exhaust temperature on diesel engine



## roliesguerra

good day sirs,

is there anyone here can help me how to rectify my problem regarding my marine diesel generator which is having high exhaust temperature on all cylinder (six cylinder daihatsu) we made alot of experiment but still the exhaust temp is still high at 220 kw load the exhaust temperature are 400 degrees celcius.



thanks


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## Basil

I'm not a diesel specialist but:

Leaking exhaust valve seats.
Worn injectors.
Air filters clogged.
Valve timing.
Is it running on Heavy Fuel Oil?


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## paulm

Do you know what the air inlet temperature is, what is the max rated load for the engine


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## funnelstays

Is the engine turbocharged,if it is check the inlet and outlet exhaust temperature
had the same problem on a Wårtsilla due to fouled nozzle ring because of incorrect mantenance and lack of turbocharger cleaning.


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## Satanic Mechanic

It's common across the cylinders , if it's turbocharged make a beeline for that.

Please send details of engine,


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## Tony Morris

funnelstays said:


> Is the engine turbocharged,if it is check the inlet and outlet exhaust temperature
> had the same problem on a Wårtsilla due to fouled nozzle ring because of incorrect mantenance and lack of turbocharger cleaning.


Hi Willie,

I agee with you this is the most probable cause.

Happy Xmas,

Tony


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## Varley

Does the current match the KW reading (W= Root 3 VI Cos Phi)? 

Ammeter is simple and most likely to read correctly, especially if any switchboard instrument transformers have been renewed, although translation to power will be less accurate.


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## Duncan112

Seen the key fail on the singularly crap split crank gear on these, allowing the cam timing to self adjust, giving weird and wonderful exhaust temperatures. Any problems synchronising the alternator?


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## mariner1945

Just a thought before any fancy detective work is done.
Have you verified all the timing from manufacturers specs ?
I have in the past, seen people chasing ghosts and they had not verified anything, just assumed !
Always good to start from basic specs and then work further to determine cause (s).


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## Hamish Mackintosh

Maybe I am missing something here but I recall working for an iron ore company in Ontario where we used 24yard self loading belly dumps to feed the plant, These machines were "Jimmy" powered, with 6-110 in the front and a 6-71 as the rear(pusher)power, the rear engine had the turbo mounted top centre with a "tailpipe" of about a foot in length, at night one could tell where the machines were worlking in the pit because the turbos would glow just about white hot, in fact when the machines came to the hopper to unload one could just about "see"the impeller going around in theform of a dark shadow thru the casing, so whats the problem ?what is the criteria for exhaust gas temps how hotistoo hot? We did not have too many problems with turbos operating in those conditions


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## Satanic Mechanic

Hamish Mackintosh said:


> Maybe I am missing something here but I recall working for an iron ore company in Ontario where we used 24yard self loading belly dumps to feed the plant, These machines were "Jimmy" powered, with 6-110 in the front and a 6-71 as the rear(pusher)power, the rear engine had the turbo mounted top centre with a "tailpipe" of about a foot in length, at night one could tell where the machines were worlking in the pit because the turbos would glow just about white hot, in fact when the machines came to the hopper to unload one could just about "see"the impeller going around in theform of a dark shadow thru the casing, so whats the problem ?what is the criteria for exhaust gas temps how hotistoo hot? We did not have too many problems with turbos operating in those conditions


It's a process of elimination - if the temperature rise is common across the cylinders then the common factors are fuel and air. The most obvious culprit is the air system as it is not as actively controlled as the fuel.

The most common fault is blocking of the exhaust passages causing exhaust gas to 'dwell' and for the turbocharger to lose efficiency. The equilibrium position of this equates to a higher exhaust gas temperature

If this is not the case then we move onto the fuel system and eventually the timing. After that we might look at ritually sacrificing a cadet to the God of diesels


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## Derek Roger

Satanic Mechanic said:


> It's a process of elimination - if the temperature rise is common across the cylinders then the common factors are fuel and air. The most obvious culprit is the air system as it is not as actively controlled as the fuel.
> 
> The most common fault is blocking of the exhaust passages causing exhaust gas to 'dwell' and for the turbocharger to lose efficiency. The equilibrium position of this equates to a higher exhaust gas temperature
> 
> If this is not the case then we move onto the fuel system and eventually the timing. After that we might look at ritually sacrificing a cadet to the God of diesels


Agreed SN but might well be a lack of water flow in the turbo charger cooler , Easy to check and fix ; check for shut off valves .
If the turbo charger is brown boveri no problem if I is a Napier change it they are junk.


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## Hamish Mackintosh

I think by the time one has moved to the timing(if that indeed is.the cuase)then there would be very little left of the top rings "or any of the other rings for that matter"


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## Satanic Mechanic

Derek Roger said:


> Agreed SN but might well be a lack of water flow in the turbo charger cooler , Easy to check and fix ; check for shut off valves .
> If the turbo charger is brown boveri no problem if I is a Napier change it they are junk.


Yup that would work but a further symptom would be high scavenge temperature


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## Engine Serang

Hi Roli,
Further to the above advice, all excellent stuff, have you tried tapping the pyrometers with your Bacho 8 inch shifter? I found it worked as often as poking about with the turboblower. Let me know how you got on.


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## Hamish Mackintosh

And if that don't fix it get a bigger hammer?


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## Engine Serang

Failing that I would tap the Third Engineer with a 10 inch shifter.


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## Duncan112

Just another thought, but if the engine has been running at low power for any period on either HFO or a blend then there s a high liklihood that the intake valves have become choked. Remove the inlet manifold/bends and, ensuring the valves are closed on each cylinder in turn you can carry out a manual decoke, replace the manifold and away you go. Mind you, operating Diahatsus on heavy or a blend never was a good idea.


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## sternchallis

Is it possible to do a turbo water wash.


Had similar trouble on a MAN (engine same as QE2 Diesels), engine was eating exh valves, turned out to be poor HFO, badly set up HOP by shipyard (so it wouldn't loose its seal, so it was just a pump) . TC nozzle ring choked up, slowing down TC, causing insufficient boost, bad combustion and so on. Ended up taking out all 14 exhaust valves and lifting two heads for burnt inlet valves. MAN said drop the exhaust cages in dhobi dust ( or teepol) and water and let soak. TC nozzle ring paint frequently with same solution (as we did not take nozzle ring off) . Eventually the carbon melted off all parts. At the same time as this was going on the 3rd, 4th ,cadet and RO were removing genny cylinder heads to replace some sleeve that MAN/MEP (tractor engines almost) said had a tendancy to drop in the cylinder. And were on our maiden voyage as well. Dressed overall and blacked out. DOP was set up the same filled serv tank with water just after bunkering.
Once the ME was back together we took it for a spin and was recommended to waterwash every 4/5 days as soon as exh temps started to rise. After that it was ok. One of the other troubles was the engine was underpowered for the ship size. Originally they had a deck less in the superstructure. This extra deck also caused a few heartaches for the Mate and stability. He said for goodness sake don't break down or we will capsize, just like a bicycle as long as you keep pedalling.

Recommend the dhobi dust & water treatment, no mechanical cleaning required.


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## sternchallis

Try a choked air cooler, perhaps full of mussels and weed.


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## John Cassels

sternchallis said:


> Try a choked air cooler, perhaps full of mussels and weed.



Then fill it full of ice cubes - that should help with the overheating


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## howardws

I assume that this generator engine is fitted in a ship. In that case am I alone in worrying about the qualifications and experience of some engine room staff?


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## Varley

It is always easy to look in from outside but what does irk on these threads is that we never get to see the outcome. Those sticking to the straight and narrow deserve this surely?

Others - John! - Moule Plombier rather than Marinier?


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## sternchallis

Howardws, that thought crossed my mind, but thought I would be diplomatic.
Never come across a Daihatsu , thought they made trucks. More of a Ruston, Allen myself . But a diesel is a diesel.


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## dannic

sternchallis said:


> Howardws, that thought crossed my mind, but thought I would be diplomatic.
> Never come across a Daihatsu , thought they made trucks. More of a Ruston, Allen myself . But a diesel is a diesel.


Unless it is a Rolls Royce!! They should never have been diesels!!
Dannic.


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## Engine Serang

Mr V,
It's difficult to have an outcome when we don't know if we have a problem or what that problem actually is. 
Mr Roliesguerra illustration of the 'problem' is so vague as to make one suspicious that it is an actual problem and worthy of study.
The Engine Serang, clue's in the name, will engage the clutch of diesel knowledge if Mr R reverts with a more fulsome description of the ailing Daihaitsu.
BTW Happy New Year.


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## Varley

I hoped that was my point. It is from the seeker after SN wisdom and wit that should feed us with the denouement. I was not criticising contributors (of either commodity).

Your Happy New Year - I Reciprocate (but will probably have to lie down later). May you have as many as you wish.


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## steamer659

Ok, here's a little tidbit to add to the discussion... I am presently C/E aboard a Car Carrier. Our Main Engine is a KHIC-B&W 8S60MCC. 14940 kW at MCR.

We did a ring inspection prior to leaving Southampton and found one broken and one collapsed ring on #2, (Top and 3rd Rings) and one broken ring on #5 (2nd Ring). We Babied the engine all the way across the WNA- averaging around 57% load...

The exhaust gas temp on #2 rose steadily throughout the crossing, necessitating backing off the fuel rack by first one, then two mm. Toward the end of the crossing, we had reduce power even more to keep the #5 temp from rising to higher than allowed temp deviation... We just left Baltimore having had to change the #2 Piston complete- we went to the "new" 14 mm low top land 14 mm top ring....

SO, there you have it- High Exhaust Temps....


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## Derek Roger

It is irritating when a question is asked and a good response given with no feed back from the questioner . Derek


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## Ian J. Huckin

Derek Roger said:


> It is irritating when a question is asked and a good response given with no feed back from the questioner . Derek


Very true...


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