ME Fuel Valves stuck

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JimMackay
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ME Fuel Valves stuck

Post by JimMackay »

Hi all,

I'm lately experiensed a miserable issue with stuck fuel valves on a MAN MAN B&W 6S60ME-C engine where cannot remove them from the cover no matter if tyring to heat them up or knock them heavily.
Not all valves suffer, just one valve in one cover and another one in another cover, certainly a few come up easily.

Happened last June, happened again today...

Not sure if previous crew tight them up too much, but not all valves are stuck on a cover, just one or two ...

Anyone having anything to suggest of why it happens?

Thanks
Jim
popeye62
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Re: ME Fuel Valves stuck

Post by popeye62 »

Morning Jim
I cannot see any difference with mounting of fuel valves between ME and MC engines i.e. there is nothing special. I have never had to heat them up.
Some questions which may be obvious:
Are you using the correct tool to remove them D09-43?
Are the valves torqued down or do you have spring packs under the holding down nuts?
Are the spring packs in good order, pin not broken?
Is there evidence of Molykote on the valve body?
Are the O rings on the body the correct size?
Was the valve bore properly cleaned and the seating re-cut last time?

What is showing when you finally get the valve out? Is there any damage to the valve body (metal to metal) or carbon build up?
Are you at 4000 hour routine o/h or are the valves being removed for another reason? (presumably they are slide-type valves and not to be treated the same as regular sac v/vs with regard to testing)
Is it possible that there are non-OEM parts? There is a recent service letter (SL2020-701) warning of dodgy spindle guides and nozzles; not relevant to sticking v/vs but something to keep in mind.
The last thing I can think of is an echo from college; don't try removing them by turning the engine.
I hope some of this helps
John
JimMackay
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Re: ME Fuel Valves stuck

Post by JimMackay »

Thanks for your valuable message John,

Well, yes. Any valve I have removed I use the correct tool and all o-rings and springs look OK but cannot tell of the stuck ones since haven't removed them yet. Will certainly look further once I succeed in removing them.
As for the tightening torque ... I'm not sure. Previous crew did it.

Reverting with more info

Thanks
Jim
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Merlyn
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Re: ME Fuel Valves stuck

Post by Merlyn »

Hydraulic puller with 10 ton plus Porto Power
Gallon Plus Gas
Pencil type ones weld themselves in with Carbon deposits.
Especially if been running with minor blow present.
Seen other makes scrap the head sometimes as even with the hydraulic puller used when welded into the head the puller left on max. overnight rips the top off the fuel valve / injector and it’s still left the body in the head.

\
Remembering The Good Old days, when Chiefs stood watches and all Torque settings were F.T.
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Merlyn
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Re: ME Fuel Valves stuck

Post by Merlyn »

I take it you have tried the obvious way ie handraulically?
Remembering The Good Old days, when Chiefs stood watches and all Torque settings were F.T.
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The Dieselduck
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Re: ME Fuel Valves stuck

Post by The Dieselduck »

I do not envy your position Jim. Steady effort and lots of patient. At this point I don't think heat is going to do anything for you. Penetrating oil and such; air hammer? certainly the handraulic for sure.
Martin Leduc
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JimMackay
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Re: ME Fuel Valves stuck

Post by JimMackay »

Not terribly proud of how i removed it :oops: since not an easy way to fit a hydraulic puller there.

Eventually injector tip broke off and left stuck inside cover, removed it later on the hard way and cleaned it nicely.

All ok now, short of one nozzle though ...
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popeye62
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Re: ME Fuel Valves stuck

Post by popeye62 »

Thanks for the photos, Jim, I have not seen anything like that before. Be proud you got it out and didn't damage the head or the pocket (I am using the word pocket for the hole in the head where the valve sits). You may need to replace the entire spindle guide as the parts are not interchangeable and it is likely damaged. Can you give us a description of photos 2 to 6?
It doesn't look like an issue of torque. Can you say that the seizure was only around the nozzle where it sticks through the head?
Has the previous crew given any details in the planned maintenance system about the fitting/problems with the valves or how it was overhauled and tested or does it just report "Done"?
How long has the valve been in?
Any sign that the valve body was leaking fuel into the pocket?
Do you get many/any fuel leak alarms when running or stopped?
Photo 1
Have the cw water passages into the head been cleaned, they look very clean? Is there corrosion in the cooling jacket o ring grooves or is it just the red rubber of the o ring. It is difficult to tell in the photo? The exhaust v/v water passages look clean also. Is the cw maintained (tested and Rocor added or whatever you use?)
What is the white stuff? It looks like it was liquid but has dried
Photos 2 and 3
Just to be clear, are these looking down the pocket? Of (1) the stuck valve pocket and (2) the other 'good' pocket
The seating looks good and the o ring position is good (the shiny ring?) but in photo 1, is that corrosion above the o ring?
What is photo 5?
That is not so good; the seating and the corrosion. If this is the valve seating it has been leaking (solid fuel/carbon) and water is present (reddish?), probably in the exhaust gas (any scuffing or cold corrosion on the liner? essential to check your water mist catcher drains are clear) but worth checking for a nozzle cw leak (not fitted?) or a hairline crack in the head? Give the head a good pressure test.
Photo 4
Is this a picture of the valve body without a nozzle or the nozzle without an end?
Put a clean valve in and check the clearance for the nozzle as this appears to be where the seizure is. Is it too big, is it too small? Does the valve have to be forced on to its seat - hole too small/nozzle too big? Are all the nozzles the same e.g diameter and protrusion through the head?
Can we have some more photos of the valve and an intact nozzle? Can we see your test rig?
Having said all that I am leaning toward a leaking seat but I will keep looking.
Report which head and valve in your PMS for the next guy.
John
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