[C4ENG]

Originally Posted by AMG

It would be interesting with more input from other owners/crew who runs two equal main generators?

When I was first learning about diesels, I was taught that the most wear and tear takes place on the motor during start up and warm up stages. And then for gens, when they start up it is right to 1200RPM or what ever with a cold block dumping fuel through the blow by into the oil pan. I was told it was best to minimize start ups for hundreds of reasons. When you are swapping back and fourth every day, that is a lot of start ups verse running one gen for 250 hrs before another start up.

[AMG]

Thanks for your input, I guess we have different use of our yachts. When I say longer trips, they will last for 4-14 days, which means max 14 startups of each generator. Then the boat is sitting for months with just a weekly startup. This is why I wanted to have both generators serviced at the same time on about equal hours.

But I understand this will be different if you are on generators for months...

[TSI AV]

Hi,

Regarding diesel-generator checkings - every manufacturer has rules, but my experience is:

1. Once a day (if running permanently) all levels, temps, pressures.
Visual inspection (loose bolts, broken lines, leakages, etc.) - depends on engine, some brands need more attention (once at 3-4 hrs), some (more reliable) have to be checked once a day or at 24 hrs.
All alarms, autostops - to be checked every 1000-1500 rhrs, but, at least, once per 4 months.

2. Every startup takes away appx. 7-8 hrs of rhrs till major overhaul.

3. If engine has more than 15000 - 20000 rhrs, normally more additional oil is needed daily.

4. :-) two things in the world need lubrication most...
diesel engines and .... w......en.

rgds,

Andrei

[Bill Arthur]

Gentlemen,Please bear with me as I`m new to this forum.
Regarding the discussion on Cat Diesels,these engines have a watchkeeping panel which will sense any Lub Oil usage(ie low level,low pressure etc).
Diesel engines like to run at full load,max capacity,as this clears any carbon deposits from the inlet manifold.If a diesel runs on low load, you will see by the exhaust!!!!In my experience in the Royal Navy,diesel generators were run alternatively to equalise engine hours,so when we were in a maintenance period,all generators could be serviced at the same time(ie top end overhauls etc).One of the biggest problems with diesel lub oil is fuel dillution,which cannot be sensed by a watchkeeping panel.The Navy check oil every 4 hours(ok we had the man power)for clarity,contamination etc..daily we checked the oil using a simple test kit for carbonaceous content etc.
If possible,in harbour,use a load bank to test diesel gen sets,or load them up starting all your equipment, and burn that carbon away from the inlet manifold....give them turbos free breathing space.
Regards.....Bill

[K1W1]

Hi,

Bill, Unless you know the particular vessel I would be cautious in assuming that it has the full monitoring package. Caterpillar have a huge range of monitoring and control "groups" or " attachments" as they refer to them in the manuals.

These are available as options when the original purchase spec of the engine is decided.

As I wrote earlier these engines may have this feature included but it's not a given.

Could you please also take the time to explain how carbon ends up in the Inlet Manifold?

[Bill Arthur]

Hi,
Most diesel engines have a watchkeeping panel, especially with regards to Lub. oil to prevent a catastophic failure.
Carbon build up is common in manifolds during low load running, due to gas byepass from the pistons,as they are not at their correct operating temp. due to expansion.Low load running can be seen normally by exhaust gases from the funnel/exhaust system being of an oily nature.
The Royal Navy have normally 4 generators onboard, 2 online....split switchboard( for normal/alternative power supplys)which we need during a war situation.Often was the case that these gen sets would operate underloaded, so we used to try and switch on as much equipment as possible, reducing exhaust scatter temperatures.
In harbour I would regularly get a load barge alongside,and load up the diesels..to 110% overload,checking governer stability,response and droop.
This would clear all carbon deposits and reduce exhaust temps. dramaticlly.
Bill

[K1W1]

Hi,

Thanks for the info.

I didn't question the provision of basic Safety Systems ( Lube Pressure, Temp, Water Temp)on the engines merely questioned the optional features like remote level monitoring.

I understand the carbon fouling of the exhaust side of things during light load running .It was the build up of carbon in the Inlet Manifold as stated in your post that I was after more info about.

[Bill Arthur]

Hi,

Sorry to confuse,but during my time overhauling diesels,Paxman,CAT,MTU,Crossley Pielsticks,it was evident of carbon build up of both exhaust and inlet manifold,,,,heavy carbon deposits around the valve guide area also.I would just like to add my engineering experience to others on this forum,because i feel this is a great website and would like to be involved in it.Diesels are old hat these days...play with a gas turbine, or water jet...more fun!!!!
Cheers Bill

[TSI AV]

Hi, people.

Bill Arthur, are You serious ?
1." Carbon build up is common in manifolds during low load running, due to gas byepass from the pistons,as they are not at their correct operating temp. due to expansion."
???????????????????????????????

2." Low load running can be seen normally by exhaust gases from the funnel/exhaust system being of an oily nature."
???????????????????????????????

3. "it was evident of carbon build up of both exhaust and inlet manifold,,,,heavy carbon deposits around the valve guide area also."

I think, this sentence explains a lot...., especially how oil can get into oil in inlet manifold. :-)

A few questions:

1. Was crankcase ventilation ok ?
2. Have You ever performed "comb. chamber leak test" ?
3. Was oil level ok ? (May be higher than max. ?)
4. Some engines have a turbo, which is lubricated and cooled by system oil, so, there are some oil seals in turbos...
5. What was ER ambient pressure ?
6. Your engines running MGO/MDO or HFO ?
7. Piston rings were ok ? Liners ovality was in range ?
8. What were rhrs since last overhaul ?

Interesting, interesting .....

rgds,

Andrei

[Bill Arthur]

Sir,
All I was trying to do on this forum was to express my experience with diesels.....I was never looking for an argument..I was just expressing my own experience.Diesels in the Royal Naval world are kept at their optimum maintenance periods,which is often overlooked in the civilian sector.

Regards
Bill

[Bill Arthur]

Dear Estonia Person.
The diesels I was refering to were gen sets 1mw/4mw not main engines.Ran on mil spec dieso.Please if you want to give me grief get your termanoligy correct,ER ambient pressure??? for god sakes.....Ambient is a temperature related subject!! Not pressure

Bill

[Northern Lights]

Bill,
Please dont be discouraged. Keep contributing. As a shore side service company I have little experience with the day to day maintenance. The information and expierence you have to share invaluable. Keep it coming.

[Bill Arthur]

Hi,

I came on this website to try an be a mentor to junior engineers/sailors.
I do not need people trying to get the better of me, or trying to be cool or smart.I would just like to pass on the knowledge,If people dont like it, then I wont waste my time.

Regards,

Bill

[YachtForum]

Hi Bill and welcome to YF,

I don't think Andrei was taking exception with you, but merely trying to understand more. If you check his profile, you will find he is interested in all things mechanical and specifically diesels. We can all learn from each other and this is the purpose of a forum... collective knowledge.

If you share information, experience or knowledge on YF, be prepared to answer some questions. People come here to learn and provide help to others. There's nothing personal intended when someone questions a statement.

[Bill Arthur]

Hiya,

Ok I`m new to this forum, and i would just like to add my engineering marine knowlegde I`m not a commercial mariner, but see things in the Armed forces context, which commercial marine have copied for years.So please I`m not trying to be funny,just trying to inform the guys of what my experiences are.
Anybody needs info on Rolls-Royce /GE Turbines please ask me.

Regards

Bill