Do turbos need servicing from time to time?

[Medskipper]

All the years I have been boating and I have never had turbos serviced! so I guess the answer is if it aint broke don't try and fix it!

But does anyone service theirs? and if so what or how is it done?

Many Thanks

Barry

 

[No Regrets]

A turbocharger has no servicable parts, as it consists of a shaft, Rotors and three or four bearings.

Normally, the seals go, or the bearings, and then they will need overhauling or replacement.

As long as you regularly change the engine oil, and ensure you warm up and warm down during periods of hard extended use, they should last years.

 

[Medskipper]

Yep I do all that,

Many thanks

Barry

 

[oldharry]

The bearings normally 'float' on oil to give the lowest possible friction, which is why oil changes are so important for Turbo engines. Commonly after very extended service the oil seals begin to wear. This allows oil into the inlet (and exhaust) manifolds, and once enough leaks through, the engine runs on it quite happily for a brief moment of racing glory! (and lots of smoke!) Also, the turbo pressure can pressurise the sump through the oil return line, which in turn forces oil out of the breather into the air inlet - again allowing the engine to run away briefly.

They can be easily checked: the manufacturers will quote a maximum end float - that is the amount of lateral movement of the turbo spinner. If the turbo is at or near it, it needs sorting.

 

[Norman_E]

My Yanmar manual has a section on cleaning the turbo by pouring a special cleaning fluid (or just plain water) into it whilst it is running. I would not dare to try it and a Yanmar service agent I asked warned against doing it!

 

[Fire99]

Ive no experience of turbocharged engines in boats but have had a number of turbocharged car engines.

I agree there are no serviceable parts in a turbocharger. There are some which you can buy replacement seals etc but and effectively recon the unit yourself but these are few and far between.

Purely from a personal perspective i would stay well clear of cleaning fluid and all that malarkey. Turbo seals like good clean top quality oil.

My advice would be to ensure the engine is at operating temperature before running the engine on boost and ensure the engine idles for a minute or two before switching off to ensure the turbo has stopped spinning before you cut oil supply to it.
Also change the oil well within manufacturers recommendation. And finally regularly use your boat and engines. Over time of non-use, oil drains away from bearings etc and dreaded condensation creeps causing wear.

Lack of use IMO is probably the biggest killer.

regards,

Nick

 

[William_H]

Small aircraft turbine engines do get a compressor wash occasionally because a build up of dirt etc can reduce the efficiency. This is usually done while the engine is rotated on the starter not actually under power.
So there may be a case for cleaning the compressor part of the turbo charger and likewise the exhaust part could be clogged with soot.
The Yanmar manual story is quite amazing. It would be ok if you disconnected the compressor output from the engine intake then you could clean it.
However unless you need absolutely max power from the engine (max boost) leave well alone. Just keep up the supply of clean oil until the turbo has cooled down. If you shut down quickly then the oil supply stops while the turbo is still very hot. The oil gets coked resulting in damaged bearings next time it runs. olewill

 

[FlyingDutchman]

I always wonder why we treat the engines in our boats different than the ones in our car. We let them warm up gently and make sure the engine is cooled down before we switch it off. We also check the oil level, coolant level, drive belts and do a visual check every time before we start them up. We even worry about cleaning the turbocharger.
I have a diesel car and I never do this type of things before I drive away. The only thing I do is drive gently untill the engine is warmed up.
Is it because we are in love with our boat engines?

 

[No Regrets]

Nope, there are two reasons.

1/ The cost

2/ The expense....

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[Fire99]

i'd add another 2 reasons:

3) Work on broken marine engines always seems to be about 500 % dearer than any work on a car engine
4) If your car breaks down you pull over and ring the RAC or AA etc, if your boat engine breaks in heavy seas you get very scared..

FlyingDutchman - well to be fair even on your diesel car engine, you should check the oil and coolant level every week which correlates with most boat owners, being every time they take the boat out..
Marine engines by their usage habits, loading (pushing tonnes of boat though water) and mere environment where they live, have a much tougher time than your daily-use car and as a result you gotta give 'em a bit more loving! /forums/images/graemlins/smile.gif

 

[spannerman]

I used to work for the largest Yanmar dealer in the country, and we washed turbos regularly as part of the service with no problems at all, we took off the aircleaner and ran the engine up to about 2500 3000rpm and sprayed a mixture of water and cleanser in short bursts. The customers used to ask for it to be done and we never had a single problem because of it.
As others have said jet turbines get their compressors stages washed to remove build up of dirt, and if you think about jet engines have to be able to tolerate water, its part of their certification process, otherwise every time you holiday jet went through a rain storm the fire would go out!
I remember reading years ago in a Readers Digest that a 747 on full power at take-off flying through heavy rain pulls enough rain drops through its four engines to empty a normal size swimming pool in several minutes!

 

[Skylark]

Turbochargers are remarkably simple devices that should give "life of the engine" service. A high Ni content turbine wheel harnesses energy from the exhaust and spins an aluminium radial compressor wheel. These two wheels are supported by journal bearings, either fully or semi floating in oil. A thrust bearing takes axial loads from either direction, depending upon operating conditions. The seals are most commonly piston rings. Most passenger car turbos have water cooled bearing housings. Most small marine do not. Hence it is prudent to ensure that the engine is cooled down a little, allowed to idle for a while, before the engine is shutdown. If not, and if there is a lot of heat within the engine, any oil lying around inside the bearing housing may thermally degrade and breakdown into carbon. These carbon deposits will find there way through the bearings and the seals and will cause wear. Of course, this is at the extreme, not at the norm. Hence the need for good quality oils, good filtration and regular change intervals.

At engine start, oil has to find its way through the pipe and into the bearings. Take a look at your own engine. If the oil feed into the bearing housing is fairly short, there will be little delay. If it's long, there will be more delay. The turbo should be designed to tolerate engine start from cold. However, a bit of mechanical empathy suggests that it's wise not to engage prop drive within a second of starting the engine. After a long time of not using an engine, it may be wise to prime. The danger is always doing more harm than good. Remember that the engine maker invested a lot of resource into designing and developing their products so it's probably unwise to think that we know best.

Air filtration is another key area. Keeping the filter clean is as much as I would do. I would not dream of trying to clean the compressor wheel. A turbo on a relatively small engine will rev to about 150,000 rpm at full load. A lot of R&D money is continuously invested by the turbo manufacturers each year in balancing technology. I would not touch the rotating group. At these speeds, imbalance usually manifests its self as noise. Increasing noise is increasing imbalance. Increasing imbalance is a failing soon to occur.

Measuring radial and axial bearing clearances is indeed the correct way to check that all is well. However, it will involve gaining access to the oil drain, usually, for the journal bearing and removing inlet and exhaust adaptors to measure axial. Far too high a risk of causing harm, in my view, unless you have real reason to think that a problem exists.

Checking seal integrity is more of a problem. It's worth thinking about the signs of any problem your facing. The turbine end seal separates oil from exhaust gas. Depending upon the conditions of operation,there can be a higher pressure within the oil, hence forcing oil into the exhaust, or vice versa. Same for the compressor seal. Oil into the induction or, less likely, air into the sump. My experience is that seals usually work extremely well unless there are other problems. Given their speed of rotation, once there's a small problem, there's usually a bigger problem soon to follow!

Your very first thought is absolutely right - it aint broke so don't fix it.

I hope this was helpful and did not teach you to suck eggs, grandmother.

 

[FlyingDutchman]

Your username is wrong!
It should read: The Turbospecialist.
Excellent reply if I may say so.

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[Guest]

"Marine engines by their usage habits, loading (pushing tonnes of boat though water) and mere environment where they live, have a much tougher time than your daily-use car and as a result you gotta give 'em a bit more loving! "

I disagree with that ... I reckon average boat engine is less hard treated than a car or other road vehicle. A car / van / truck is thrashed to get acceleration out of it etc. - is often pushed to near rev limits ... Average yottie engine plods away at economic revs rarely above 1/2 throttle - apart from odd bursts to beat a tide etc.

I reckon that boat engines die not through hard use - but lack of use and marine environment corrosion etc.

IMHO of course !!

I'd like to see a car engine run as sweet as my 40yr old Perkins ....... after similar number of years but hammering away on the roads ...

 

[alb40]

I would agree that a marine engine is worked much harder than a car engine.

A boat's engine is continously loaded by the propeller, so although a cars engine goes through periods of hard accelleration, the rest of the time they run very lightly loaded, and you only rest your foot on the loud pedal just enough to keep you going. Even on hills, the engine is not on full load even if your foot is down, because you are not using full engine speed, but using around the point of maximum torque on the rev range, so they engine is working at its most efficient pulling power.

In comparison, boats engines are heavily loaded. They are pushing tonnes of boat through water, with only a single gear to play with. Sail boats are normally very underpowered, with small engines working hard to push a heavy displacement boat with small amounts of power. Motor boats often use all the engine can give to pull the boat onto the plane or achieve maximum speeds.

My 40 odd year old perkins also run sweet. Its because they are old heavy low reving units, with big capacity and low power. My 14 year old ford diesel car was also still going well too, and had been around the clock a couple of times before I had to get rid of it as the bodywork didn't fare so well.

im not so sure the modern high power high reving diesels would fare so well. High power coupled with the high stresses in boats equals breakdowns for these new units. e.g. the new volvo D series engines seem to be failing at an alarming rate, but the same unit in a vehicle fares much better.

Alex

 

[William_H]

There is a vast difference between a turbine engine and a diesel if you throw water into it. A little water into both is fine even gives more power (on a turbine) however if you completely flood a turbine it might lose power. If you put enough water into a diesel whilke running you can get a hydraulic lock. That is when the piston stops becuase the water in the chamber can't be compressed but the crankshaft keeps turning. This usually results in bent or broken con rod.
So although I don't know much about it I would be vary wary of spraying water into a turbo charger on a running diesel. A little bit might be vapourised OK a lot = crunch. olewill

 

[BrendanS]

Very useful, and far better input than the usual smoke and fluff that most post here, who actually know nothing about the subject.

 

[MapisM]

I can only second Brendan's comments. Is your job related to this subject somehow?
Mind you, after such interesting inputs just at your third post, we are entitled to expect even more valuable contribution for the future!...

 

[PaulJS]

If the Yanmar handbook details a procedure for water washing the turbo it will presumably be recommended as part of their maintenance schedule.
As to previous posters thoughts on whether a car or marine engine has an easier life I would absolutely agree that the marine engine has an easier life: it runs at or about optimum load for a much higher proportion of the time, this is much "kinder" to any engine rather than constant large changes in load as experienced in automotive engines, engines are designed so that all of the various clearances are at optimum values and they are at their most efficient under working conditions, thus a steady medium to heavy load is preferable to a varying load.
On large marine diesel engines we regularly injected small measured quantities of fresh, preferably distilled, water into both turbine sides and compressor sides of turbines to keep the blades clean, although in the past other cleaning chemicals and various substances such as ground nut shells have been used for their cleaning properties. On medium speed engines (Approx 750kW to 4500kW) we only washed the turbine side of the turbochargers by pressurising a small container of water with a bleed of pressurised air from the compressor side and injecting a measured quantity of water as a spray into the turbine side - to alleviate previous concerns about injecting water into an engine causing hydraulic lock, the amount of water is miniscule in comparison to the amount of air being induced by the engine, probably comparable to the quantity of fuel injected.
However, on smaller engines such as generator sets (up to approx 500kW) the planned maintenance of turbochargers is normally just a periodic check of the rotor end play, regular oil, oil filter, and air filter changes. They are normally completely stripped and overhauled during major engine overhauls.

I don't think that I've actually shed any light on this debate, but some of what I've said might be slightly interesting to some forumites.
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