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So, you think pulling a head off on a landy is hard work?


TheRecklessEngineer
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Some of you might remember I started a new job a while back, and I posted some piccies. Here's part 2. (BTW, no LR content whatsoever, but my last post seemed to go down well as it has 'extreme' engineering content, so I thought I'd do another one. Mods, remove if you wish!)

For those that don't remember, I'm currently training as a marine engineer on board shipping vessels. Since my last post, I've spent 8 months or so on dry land doing the academic bit, and I'm now back at sea where I will remain until late January. So I'm still not fully qualified, but getting there slowly.

Anyway. The last few days have been somewhat interesting: We've got 2 big diesels to push our ship forwards, both pushing out about 10MW @ 500rpm (These are actually quite small as ship engines go, but then this is only a ferry!). We've been having some issues with our injectors - one cylinder in particular had an EGT 50 degrees higher than the other 7. We wound the fuel back on that cylinder, however the EGT remained high.

Thursday morning, 2am. Oil mist detector flags an oil mist in the crankcase (vaporised oil) and shuts down the engine. It happened to be the one that was driving the genny too, so we blacked out. Further investigation revealed a complete lack of compression on our suspect cylinder. So...alarm bells ringing, suspect melted piston.

For some reason this computer isn't liking the forum software, so all the photos are going to end up at the bottom of this post.

Anyway, all good fun - cylinder head weighs in at about 1500kg, piston at around 300kg. The crown (the bit that melted) is detatchable from the piston which makes it considerably cheaper to replace. The underside of the crown is shown below - lots of corrugations to allow for piston cooling. The webs actually marry up with the injector spray pattern to apply extra cooling where most of the combustion takes place - this is also where it melted.

I didn't get a photo of the injector, but it is in a sorry state. Completely gunked up. It's been sent ashore for further testing as it only had about 300 hours on it.

None of us had done this before, so we took it fairly slowly over 2 days. It's all back together now, and just awaiting running in. Enjoy! :)

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Yup, I'd be Warsash too. I recognise your vehicle - kinda hard to miss in our car park! I had my landy down for a bit earlier this year, but I chewed through £50 in petrol in a week, so I took it home again.

So you'd be on a proper ship then - I'm stuck on a ferry for the time being, but it does mean I get to go home for 2 weeks between trips on this sea phase.

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Yes, that piccie was taken on the test bed.

The real version is fitted aboard the Emma Maersk. The ship I'm currently on was parked up next to her in Spain once. On board my ship, stood on the bridge wings (highest point, deck 9) and still looking up at the deck of the Emma Maersk. She's huge, and certified to sail with only 12 crew. :blink:

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on my last ship wich has a scott sulzer rnd 90 8 cylinder fitted.

the pistons weigh 4.75 tonnes :blink: with a bore of 970mm amd a stroke of about 2 meters.

at max chat (120 rpm) you could see the heads rising at tdc

the 2 turbos were the size of a 90! :blink: there was also a electric auxy blower!

i think it made about 17500kw not bad in a ship that only weighs 22000 tonnes

22 knots flat out :)

i will try and add some photos later

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