Connecting Rod picture

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Big Pete
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Connecting Rod picture

Postby Big Pete » Mon Jan 03, 2011 2:10 am

Any thoughts?

BP

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It is always better to ask a stupid question than to do a stupid thing.

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D Winsor
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Re: Connecting Rod picture

Postby D Winsor » Mon Jan 03, 2011 4:54 pm

It's hard to tell without other points of reference but it looks like the result of an over torqued tie bolt on a 2 piece rod.
Troubleshooting 101 "Don't over think it - K.I.S.S. it"

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JK
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Re: Connecting Rod picture

Postby JK » Tue Jan 04, 2011 1:33 pm

A fine dye prenetrant job!

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Big Pete
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Re: Connecting Rod picture

Postby Big Pete » Sun Jan 09, 2011 10:40 am

I had a message from the Office, informing me that a Sister ship had found cracks in her generator Con Rods and ordering all ships to check there rods.

We eventually found 15 cracked rods out out of 24 in the generators, Wartsilla Vasa type. Two of the engines, 5 out of 6 cracked rods each, had been overhauled in the previous 6 months and were supposed to be "Dye Penned" at that time, but no cracked rods were found then. The other 6 cylinder engine also had 5 cracked rods and the 4 cylinder, (which was nearly due major overhaul) was the only one safe to run.

I found out that the Engineers were not cleaning the parts before spraying with dye and were not washing off all the visible dye before appplying developer and were then spraying on developer as if it was shaving foam!!
To get good results the surfaces must be completely oil & grease free, the dye should be lightly and evenly sprayed on and left to harden, then all visible dye washed off with the cleaner before finally barely covering the surface with developer.
In my experience you always run out of cleaner from the kit first, however it is perfectly OK to use ordinary electrical cleaner or brake and clutch cleaner instead of the cleaner in the kit.
My suspicions were aroused when we looked in the stores for Dye Pen and found 6 tins of cleaner, 2 of dye and no developer

The picture shows the connecting rod sitting on the crankpin with the bearing keep and lower shell removed as well as the B.E. studs.
When the Engineers were refitting the studs I found they were flogging them up with a big spanner & hammer, so I had to get them to check the instruction manual to find the correct tightening torque and procedure and to make sure they tightened the nuts of the bearing keep correctly.

When we started to receive replacement rods, the Third measured the cracked B.E.s for wear and ovality and his figures looked O.K., but when they were checked it was found that he was adding an extra zero after the decimal point on all his micrometer readings so the ovality and wear was way beyond the makers limits, instead of being inside them.

I emphasise, nothing wrong with the Wartsilla Vasa, just abuse by the Engineers.

BP
It is always better to ask a stupid question than to do a stupid thing.

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JK
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Re: Connecting Rod picture

Postby JK » Thu Jan 13, 2011 5:43 am

Wow, dye penetrant is super easy, those guys don't read instructions?
You must just shake your head at seeing all of this.

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Big Pete
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Re: Connecting Rod picture

Postby Big Pete » Sat Jun 18, 2011 1:11 pm

Bit of a late reply JK but I joined a ship before you made your reply and only just got back.
No one told me how to use the Dye Pen kit when I first used one, but I had the advantage that the instructions were in English and I am a Native English speaker.
On this ship all the Engineers , 2nd, 3rd, 4th, & Fitter were Filipino and the Dye Pen instructions were in Korean, which is not a lot of use to most of us.
BP
It is always better to ask a stupid question than to do a stupid thing.

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JK
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Re: Connecting Rod picture

Postby JK » Sun Jun 19, 2011 1:36 pm

Welcome home, hope you have a good summer break.
I spoke with the assurance of a person that was actually given training on using dye-pen :oops:
It is easy, if you can read the instructions in your language.

I was once asked to dye-pen a head. When I did so, the dye clearly showed a crack running parallel to the landing the across it and also between the valve ports. When I showed the old Chief, he looked at me, looked at the cracks and said, can you weld it? Ummmm, no.

Years later, after paying 25 k to purchase replacement heads, I now know where that question came from.

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JollyJack
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Re: Connecting Rod picture

Postby JollyJack » Mon Jun 20, 2011 6:19 am

In the commercial world, cheapest is always the first option, and it's cheaper to weld a cracked head initially. The "pay now or pay more later" doesn't seem to register with beancounters, so a 5 bob job turns into 10 quid!
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