Is it really necessary to oil change at 100 hrs these days.

[Marsupial]

YES

Change the oil every 100 and filter every 200, you could pass the engine on to your great grand children

 

[Avocet]

I stand firmly in the "it's not that simple!" camp! I have a raw water cooled engine that went out of production the best part of 20 years ago. I have no interest therefore, in the bottom end lasting any longer than the cast iron from which the cylinder head is made!

Plenty of modern car diesel engines can do 20,000 (AND MORE) miles between (synthetic) oil changes and last just fine. Renault (and others) might have a problem with turbos but I wouldn't put my hand on my heart and say that the problem would not have arisen if you'd changed the oil more frequently!

To my mind, the single biggest difference is that boat engines (little raw-water-cooled ones at any rate) run stone cold and don't get the oil anything LIKE hot enough to evaporate any fuel that gets past the piston rings (or through the fuel pump seals) off. As if that wasn't bad enough, most of them don't often run for very long - just long enough to get the sails up in my case. As has also been said, they're very low-tech affairs compared to car engines. The fuel isn't metered anything like as precisely. My engine doesn't even have an oil pump or an oil filter either. For all these reasons, I'd be inclined to use the cheapest oil of the correct specification and change it every year.

 

[Marsupial]

Point taken BUT car engines are very different beasts from boat engines (I used to be involved with the manufacture both for a little firm called FORD I was there at the dymo when we tried to turbo charge the 6cyl truck engine).

One of the quickest ways to destroy an engine (apart from wanton violence(turbo it??)) is to run it with dirty oil. We did amazing things to car engines to extend oil change intervals but I wouldn’t advocate any of them if your priority is reliability and endurance. And as others have said turbo bearings are very fickle, dirty cold oil will destroy them in seconds, personally, I wouldnt have a turbo on a boat, its the wrong application.

There is never any doubt about the advice to keep the oil clean.

 

[Drascomber]

Oil life is also affected by filter performance.

Some marine engines have old technology filters. Some e.g. small 4 stroke outboards, have no filter at all.

 

[Scotty_Tradewind]

Somewhere I heard this explanation, is it true?.........
As a diesel engine is used, sulphur in the fuel is burned and Sulphuric Acid is formed. This finds its way down through the cylinder bores and via the valve guides into the engine oil and is the main reason to change your oil before laying up the boat for the winter.
Diesel engines appear to be more prone to this than do petrol engines. Sulphuric acid = corrosion of the inner parts of an engine. As boats sit around a great deal of the time and this cocktail ferments in the sump, I would have thought it wise to change more often?

 

[Marsupial]

Yes spot on, and it happens in petrol engines to. Of course any moisture in the oil from condensation only makes it worse. SO to extend the life of oil in cars crankcase ventilation was increased to dry out the oil, oil capacity was increased to disperse the particulates thrioughout a larger volume and oil filters were made larger and finer to catch more of them. HOWEVER the oil bipass which operates when the oil and the engine is cold means that unfiltered sludge can make its way through to the bearings. Good bye turbo! AND all the bearing surfaces get treated to a quick lapping until one day there's nothing left to lap.

Most modern diesels even the agricultural ones we use in boats have some sort of positive crankcase ventilation these days.

You will realise that cold clean oil dry oil wont have quite the same deleterious effects on the the engine internals under these conditions.

 

[castaway]

With my Perkins 4107 I figure that 50 hours at 50mph as a truck or van unit it would cover 2500miles....

So as I do 100hrs a season I change mine usually whilst on my summer cruise and at the end of the season before laying up.

50hrs per oil change, and the engine starts on the button with no preheat (in the summer)

I economize on almost every thing except oil changes !

Regards Nick

 

[sailorman]

when the Perkie 4107 was powering a Road Compressor it would have done in excess of 40 hrs per week @ almost full revs. How often was its oil changed then??

 

[Marsupial]

Not the same perky 4107, it had a bigger sump and a slower rev. It was hot most of the time and at a constant rev exactly what a boat engine isn’t. Its a different application and is actually beneficial to reliability and endurance.

You’re comparing chalk with cheese here.

 

[castaway]

Yes and who gave a flying fluke when it packed up or belched smoke ??

My Mrs Perkins however, is loved, treated accordingly, and expected to perform on demand !

Nick

 

[sailorman]

I understand your point of view exactly.
i am asking the question regarding commercial applications where the engine had a much tougher life

 

[sailorman]

I wouldn't argue with the greater sump capacity but marine engines do run most of the time @ Constant revs & not high revs compared to the static engines fitted to Civil Engineering Plant

 

[Avocet]

I believe the sulphur levels in fuel are much lower these days than they used to be. Is that true and if so, are the effects still significant?

 

[vyv_cox]

In general yes, sulphur levels are lower, although red diesel is probably sourced from fuel with higher levels. Provided the oil is of suitable base number this should not specifically be an issue. However, the condensed acids referred to higher up are not only sulphur based, 'weak organic acids' that result from diesel combustion include carbonic, naphthenic and many others.

 

[r_h]

[ QUOTE ]
This is a function of engine design more than oil development.

In many marine engines which do not have common rail injection the fuel pumps are mounted on the crankcase and so spill leakage from the pump plungers goes to the crankcase. This dilutes the oil hence the need for frequent oil changes.

The Nanni and Beta engines come into this catagory as they meet emmision requirements without going to common rail etc.



[/ QUOTE ]


What interests me is that these engines are marinised industrial motors that are designed to run 24/7. When used for pumps and refrigeration units etc the oil surely doesn't get changed every 4 days.

Granted, stop/start running is much more harmful on a per-hour basis than continuous operation, but it does seem that oil changes every 100 hours is excessive. The cynic in me is tempted to believe it's a money-making scheme for marine engineers.

 

[Marsupial]

Dont be cynical were're not all marine engineers and I susupect that few who read this forum would actualy pay for an engine oil change. /forums/images/graemlins/smile.gif

As usual this debate is becomming more complicated than it needs to be. But this little piece of fact may interest you.

Had a car (Merc not that it matters) that calculated its oil changes and service intervals as you drove. Took it across europe long runs at constant speed and the watched as the next service dissappeared into the far distant future, returned to normal use in the UK stop start 20 mins in traffic short hops, cold starts and watched the service interval come rapidly back to the present. How you use it matters

As I left the motor industry there were lots of experiments going on to establish optimum oil change intervals. The motivation was political - to save oil - not technical to see if we could "cheat engine death" so it was a "how far can we go without changing the oil and still convince the customer that his worn out engine is the result of fair wear and tear and not neglect" sort of thesis. Not a lot of good on a boat (IMHO)

The advice, for what its worth is to keep the oil in your engine clean and dry if you want ithe engine to have a long service life. IF you run the engine 10 hours a day every day by all means extend the interval to 300 hours (once a month) and I would agree . . . . . does any of that make sense?

I have no commercial interest in any oil company or marine engineering company or engine suppy company - I am just an engineer who used to make and tune engines and thinks he knows whats best for an (any) engine.

 

[RAI]

I had a new company VW diesel car, after 1000 km I took it in for a start of life service. (Old git!) they said, the first service on this car is at 50 000 km.

 

[Refueler]

[ QUOTE ]
With my Perkins 4107 I figure that 50 hours at 50mph as a truck or van unit it would cover 2500miles....

So as I do 100hrs a season I change mine usually whilst on my summer cruise and at the end of the season before laying up.

50hrs per oil change, and the engine starts on the button with no preheat (in the summer)

I economize on almost every thing except oil changes !

Regards Nick

[/ QUOTE ]

My 4-107 started even when I had 4 yr old oil in it.... so ?

I now change it at reasonable periods - but not at set intervals of hours or season.

OK - ignoring my personal decision on my own engine. Lets look at the preferred better answer. Do as the engine manufacturer says. Engines are being made with finer tolerances and oils are trying to keep up. It is fair to say that lubricating oils are blending to try and provide the correct grade - but still lagging a bit. Synthetics are a solution - BUT be careful these are designed for high performance engines.
Some say here that boat engines are agricultural and not as high spec cars. OK true when comparing ultra modern diesels - but most boat engines are similar to established taxi / van engines AND shore based static engines that required reliable service of not so long ago. Dependable engines that could run and run and run.
Until recently my lab looked after imports of Base Oil to UK for blending into Lub Oils for various trucking and Transport enterprises. Very few used any synthetics and it was mineral based. I read various posts about types and it really then comes down to the additives and blend used.

Keep to sensible middle of road grades, change at reasonable intervals and you should be OK. Ultra cheap oils are usually reconstituted / recycled with additives to replace viscosity etc. Expensive are usually expensive - Ok with an additive particular to the grade to differentiate from others.

Summary : Cheap oils - IMHO do not try to push intervals of change. Keep to schedule and not risk failure of oil properties. Spend more on major oil company named oils and you should be able to extend your change times but is it worth the extra cost ? I don't know. Buy expensive oils ? Your choice ... Your peace of mind.

 

[NorthUp]

If you re spending what you consider a serious amount of money (its all relative..) then spend a few quid more and send a sample of your oil to one of several testing labs- google oil testing or sos caterpillar for examples.
From memory its about £50 per sample,and will tell you how the oil is performing in your own particular engine, under the conditions you use it. If you do it regularly, you can establish trends in the analysis, and spot developing problems before serious damage occurs.
Most large fleet users, both marine and road haulage or plant operators do this, and none are famous for unnecessary spending!

 

[Refueler]

[ QUOTE ]
If you re spending what you consider a serious amount of money (its all relative..) then spend a few quid more and send a sample of your oil to one of several testing labs- google oil testing or sos caterpillar for examples.
From memory its about £50 per sample,and will tell you how the oil is performing in your own particular engine, under the conditions you use it. If you do it regularly, you can establish trends in the analysis, and spot developing problems before serious damage occurs.
Most large fleet users, both marine and road haulage or plant operators do this, and none are famous for unnecessary spending!

[/ QUOTE ]

My Lab can do the tests - but I don't bother. At price of oil change for my one boat at about 6 litres ... why ?