Common Rail Engine 48/60 cr

A place to exchanges questions and ideas of a technical / procedural nature. Go ahead, try to stomp us !
Atlantic
Deck Plate Wanderer
Posts: 23
Joined: Tue Sep 18, 2012 3:51 am

Re: Common Rail Engine 48/60 cr

Postby Atlantic » Fri Aug 04, 2017 6:09 pm

On one ship I worked on, I believe it was wärtsilä wasa32 engine, we had problems with our fuel pumps because the fuel temp was to high, turned up to lower the viscosity. Temp somewere over 150C I believe.

User avatar
Merlyn
Fleet Engineer
Posts: 782
Joined: Wed Dec 25, 2013 7:19 am
Currently located: South Coast UK

Re: Common Rail Engine 48/60 cr

Postby Merlyn » Thu Aug 10, 2017 12:57 am

Dave W's comments re research concerning truck engines and marine engines running on LFO brings to mind experiences I have encountered with same.
Where I am at we also in addition to Marine Engineering repairs undertake truck repairs from 44 ton artics down.
We have workshops capable of taking articulated trucks with tri- axle trailers attached.
The major problem that ensued with common rail predominating the trade is not only the old familiar dirt in the fuel but missfuelling happenings.
This, with CR is very serious indeed with major, major damage possibly happening to the whole CR system from the tank/ stackpipe through to the injectors.
It is not unusual to be called out to a missfuelled vehicle on a regular basis, maybe once or twice a month.
Two saddle tanks containing sometimes upto and sometimes over one hundred gallons of Petrol where misfuelled is not an uncommon occurrence .
The defect reported is knocking noises present so the first step is to start the engine.
The noise is always the same.
Explosions in the crankcase, this is quite scary as there are no crankcase door relief valves fitted here, the only link with atmosphere is maybe a breather fitted but it is no substitute for relief valves arrangements.
There is without doubt a man in the sump/ crankcase with a sledge giving it plenty.
The noise is the very similar to the " old" mechanical systems but the rectification methods being CR are entirely different.
Some of the original Bosch CR systems in the mid eighties and ninety had a separate LP pump fitted in the fuel tank( s) and the very act of just switching on the ignition without engaging the starter would energise the LP pump thus immediately pumping fuel upto the HP pump at around 40 psi.thus rendering the system to cause damage.
A start to pull the vehicle off the pumps would result in the missfuelled petrol/ diesel mix being pumped upto the HP pump and thence onwards to the injectors at maybe 25,000 psi plus in some cases.
In the old days you could normally pump out the system, remove and test the injectors maybe( if miss firing ) and strip and clean the nozzle/ pintles and reset on your Hartridge pop tester.
Not so now at all.
It is worth mentioning at this stage that some of the early fuel systems in trucks and ships launches etc that were Bosch suffered from the LP pump impeller bearing to pre age itself ( without missfuelling ) by virtue that the ball bearing race sat in the pump casing ( not the motor end ) started to break up causing spalling to occur.
I.e. Very small grinding dust type particles from the ball bearings themselves to enter the fuel system.
This, after a period of time became a point to go straight to when attempting to diagnose faulty runners with the MIL light on.
In the early stages ( mid eighties approx ) it took us days to work out why this spalling of grinding dust type material was coming from and like all manufactures not wishing to admit any liability in their products you really were on your own, ( as usual )
This talcum powder type going dust would go through the system and the injectors would go down first followed normally by the HP pump.
Not understanding in those early days ( and with no help from anyone ) where this spalling was coming from you could spend over ten thousand pounds renewing all the faulty parts, for it to run ok for several weeks and for it to break down again as the generator of the source of the failure was still churning out grinding dust, i.e. The LP pump.
Once you had been caught by these problems you always renewed the LP pump but to begin with no- one knew so you were very much on your own.
However back to the missfuelling, had the vehicle been driven any distance we had some engines whose sump joints had been blown out slightly causing an oileak to occur as a result of crankcase explosions.
We even had some with timing case and rear mains that started to leak after all the repairs had been carried out.
The rear main and the timing case oilseals, if they were the spring loaded lip seal type they were normally ok as the explosion normally drove the lip down onto the crank/ front pulley but the older engines with the graphited two halves packing type seal on the rear main could be a problem.
To change this type of rear main oilseals entailed removing the crank in order to access the top half of the packing sat in the block unlike the bottom one sat in the rear main bearing carrier cap.
So careless missfuelling could become a very expensive damage repair exercise resulting in some cases of the engine being written off.
Manufactures quickly began fitting fuel tank necks of different diameters to coincide with the petrol/ diesel nozzle diameters but it still doesn't prevent missfuelling happening on rare occasions versus the " old days "

BP's remarks concerning different people's interpretation of engineering discriptions reminds me of " Wrist Pins " V gudgeon Pins and adjusting the " Lash " which means over here adjusting the tappets I believe.
Finally of course H2O was always a common factor in fuel systems causing havoc in my career Causing numerous breakdowns and aside from fuel systems H2O being non compressible would result in cracked heads and S shaped rods.
So I hope Top Dead Centre gets to the bottom of the problem either by renewing it all and it sails on happily ever ( and no one knows ) after or the true cause is revealed in order to ensure it does not happen again.
Interesting one as it seems quite a common engine fitted in a lot of ships ( or variants of )
So when you folk out there are dreaming of that retirement and stick the wrong nozzle in your tank remember, Diesel in the petrol tank = about £200 bill, petrol in your diesel tank = deep shit.
You may as when put that man with a grinderette in the fuel system.
Or a large tin of coarse,
( Grinding paste that is )
Remembering The Good Old days, when Chiefs stood watches and all Torque settings were F.T.

TDC
Tanktop Cleaner
Posts: 17
Joined: Wed Jul 19, 2017 3:40 am
Currently located: St. Johns, NL

Re: Common Rail Engine 48/60 cr

Postby TDC » Wed Aug 30, 2017 4:41 pm

Thanks to all for comments and input. I haven't replied in a while as I was going down so many different directions I would never live long enough to type it lol. Fuel samples are benchmarked at above average for Canadian supply HFO 380( according to Viswa Lab) Catfine levels between 15ppm and 19ppm before engine supply. Water content .1% . Iron a tad on the high side but was also high in the bunker so this rules out the deteriorating component in our fuel system theory. I have tracked down an expert on this engine (ex MAN ) who tells me at one point 90% of all control valve failures we manufacturer defect however MAN does not seem to agree. To date since the vessel was built in 2012 we have changed over 50 control valves which would kind of align with the advice on manufacturer defect. Some of the failed injectors and pumps have been analyzed by MAN with a very short , detail lacking report which indicates fretting caused by foreign material some low alloy some hard surface material but no conclusion could be made. One of the issues with this system is that one failed component can in theory take down a whole bank via the common rail so a failure of one pump, could tale out other pumps and injectors . We have done a lot of fine tuning to our filter cleaning procedures and have switched to 180cst as a trial which has resulted in 3 weeks of trouble free operation which almost leads me to believe the decrease in temperature from 138degc to 120 degc is the answer( but as per design should not be the case ) time will tell. I still believe design issue and known problems being swept under the rug by MAN with the intent to sell more parts and not tip the market off that the technology is flawed. Wartsilla has accepted that their CR technology is flawed and have supported some customers to convert back to conventional pumps.

BP was correct with the land ring , that is what I meant
stay tuned
TDC

User avatar
Merlyn
Fleet Engineer
Posts: 782
Joined: Wed Dec 25, 2013 7:19 am
Currently located: South Coast UK

Re: Common Rail Engine 48/60 cr

Postby Merlyn » Sat Sep 09, 2017 8:37 am

Further pondering this subject anyone stripped injectors HP pumps etc to suss out the EXACT cause of failure?
I.e. Scoring , nozzle condition, pump bearings/ valves etc?
Sensor windings, resistances etc within spec?
Obviously in the fuel system any spalling from HP pumps areas would possibly write off injectors etc although it maybe only one roller/ ball bearing race causing it all?
Do you carry any test kits at all even if it only does function tests?
Remembering The Good Old days, when Chiefs stood watches and all Torque settings were F.T.

User avatar
Big Pete
Engineering Mentor
Posts: 813
Joined: Fri Apr 24, 2009 11:18 pm
Currently located: Solihull, England

Re: Common Rail Engine 48/60 cr

Postby Big Pete » Thu Oct 05, 2017 2:24 am

https://www.imarest.org/themarineprofes ... ine-engine

There is a replacement engine out, maybe it would be easier to re engine?
It is always better to ask a stupid question than to do a stupid thing.


Return to “The Workshop”

Who is online

Users browsing this forum: No registered users and 1 guest