Engine Service Intervals

[Irish Rover]

My engines are rated for max 3,800 rpm and my boat has a max speed of 24 knots. I think most users would see 2,600 rpm giving 16/18 knots as a reasonable cruising speed which would give you a range of around 4,000 miles between the recommended service intervals of 250 hours. I rarely run my engines above 1300/1400 rpm which gives me a speed around 8 knots and a range of around 2,000 miles between services. I know all the guff about diesel engines needing to be worked hard, but my wife's X Trail still has the same kilometre travelled service interval, regardless of how she drives it. So is there an argument (YBW loves an argument) for me servicing less often?

 

[wonkywinch]

Oil acts as a lubricant, it cools, seals, cleans and prevents corrosion. And it's cheap. I wouldn't skimp on the most important part of servicing, ie oil and filters.

 

[Irish Rover]

Oil acts as a lubricant, it cools, seals, cleans and prevents corrosion. And it's cheap. I wouldn't skimp on the most important part of servicing, ie oil and filters.

It's the same oil they use in my wife's X Trail.

 

[capnsensible]

What about taking the advice of the people who designed and built the engines?

 

[Irish Rover]

What about taking the advice of the people who designed and built the engines?

I do. I'm asking is there a case for doing otherwise. I want to understand the reasoning. I'm pretty sure my engines are also used in Toyota trucks. Do they have hour intervals or Km intervals.

 

[wonkywinch]

I do. I'm asking is there a case for doing otherwise. I want to understand the reasoning. I'm pretty sure my engines are also used in Toyota trucks. Do they have hour intervals or Km intervals.

Or even cycles? Car manufacturers use mileage as it's the simplest most visible indicator. We all know that lots of short journeys knacker car engines. I wouldn't trust the maker to tell us anything other than what will maximise the life of their product just until the warranty expired, ie 2-3 years.

Despite "long life servicing" (2 year oil changes) appearing on German marques a number of years ago, I have changed my oil annually on every car I have owned. The missus MX5 says the diff and gearbox are "sealed for life" and Mazda won't even sell you the oil but I change that too. As I said, oil is cheap, the flip side isn't.

 

[Irish Rover]

Or even cycles? Car manufacturers use mileage as it's the simplest most visible indicator. We all know that lots of short journeys knacker car engines. I wouldn't trust the maker to tell us anything other than what will maximise the life of their product just until the warranty expired, ie 2-3 years.

Despite "long life servicing" (2 year oil changes) appearing on German marques a number of years ago, I have changed my oil annually on every car I have owned. The missus MX5 says the diff and gearbox are "sealed for life" and Mazda won't even sell you the oil but I change that too. As I said, oil is cheap, the flip side isn't.

I commend your care and attention towards your machines, but it doesn't answer my question.

 

[capnsensible]

Yay, another manufacturers conspiracy theory! Didn't take long.

 

[wonkywinch]

Yay, another manufacturers conspiracy theory! Didn't take long.

Google the issue with the small Ford ecoboost engine wet belt problems to reassure yourself that car makers have the highest integrity (or even the Ford Pinto fuel tank issue if you want to go back in time).

 

[Irish Rover]

Yay, another manufacturers conspiracy theory! Didn't take long.

Google the issue with the small Ford ecoboost engine wet belt problems to reassure yourself that car makers have the highest integrity (or even the Ford Pinto fuel tank issue if you want to go back in time).

Please, guys, don't take this thread off on a tangent. Start another thread if you wish. I'm asking a serious question and I'd like to keep the thread on point.

 

[billskip]

My engines are rated for max 3,800 rpm and my boat has a max speed of 24 knots. I think most users would see 2,600 rpm giving 16/18 knots as a reasonable cruising speed which would give you a range of around 4,000 miles between the recommended service intervals of 250 hours. I rarely run my engines above 1300/1400 rpm which gives me a speed around 8 knots and a range of around 2,000 miles between services. I know all the guff about diesel engines needing to be worked hard, but my wife's X Trail still has the same kilometre travelled service interval, regardless of how she drives it. So is there an argument (YBW loves an argument) for me servicing less often?

They are your engines, you can do what you like, but I think usage comparison with a road vehicle is not a realistic wear and tear value. I would think the X Trail will do more kilometers per revolutions than your boat, an hourly comparison woud be more acceptable.
Oil although it's already thousands of years old before you buy it, it is a processed lubricant that you buy and woud deteriorate if put in an engine and never used.
Oil has a thickness and is a buffer between parts, when that oil buffer gets contaminated it can act as a less favourable protection so in my opinion
keep the 'blood' of the engine in best condition is a good idea..

 

[wonkywinch]

My engines are rated for max 3,800 rpm and my boat has a max speed of 24 knots. I think most users would see 2,600 rpm giving 16/18 knots as a reasonable cruising speed which would give you a range of around 4,000 miles between the recommended service intervals of 250 hours. I rarely run my engines above 1300/1400 rpm which gives me a speed around 8 knots and a range of around 2,000 miles between services. I know all the guff about diesel engines needing to be worked hard, but my wife's X Trail still has the same kilometre travelled service interval, regardless of how she drives it. So is there an argument (YBW loves an argument) for me servicing less often?

OK, my thoughts (sorry, not a definitive answer) is that the X Trail may be an older design where the service interval isn't modified by the number or start stop events or the style of driving whereas newer engines are. The manufacturers intervals are probable worst case intervals as their cars are marketed in all sorts of environments with varying air density/quality, fuel quality etc.

A boat engine generally does the same rpm whilst it's running so doesn't have as much stress as a car engine that is accelerated many times up and down the rpm range so that is probably kinder for it. On the other hand, the environment is generally worse for a boat engine.

Swings and roundabouts. Oil is cheap, why scrimp?

 

[Irish Rover]

Servicing is about much more than oil and filters but let's stick to that for now. What degrades the oil and filter? Is it age? I'm putting up 50 hours per month, 12 months of the year so I need to change every 5 months. I don't think age is a factor there. I burn around 5 LPH @ 1400 rpm. I think it's around 25/30 LPH @ 2600 RPM. Is it not the contaminants from the combustion process that degrades the oil and clogs the filter?

 

[billskip]

Oil picks up contamination, moisture, carbon and metals and becomes abrasive.

 

[Irish Rover]

Oil picks up contamination, moisture, carbon and metals and becomes abrasive.

OK. But is it not reasonable to assume most of this comes from burning diesel and any metal is more likely at higher revs?

 

[dunedin]

Servicing is about much more than oil and filters but let's stick to that for now. What degrades the oil and filter? Is it age? I'm putting up 50 hours per month, 12 months of the year so I need to change every 5 months. I don't think age is a factor there. I burn around 5 LPH @ 1400 rpm. I think it's around 25/30 LPH @ 2600 RPM. Is it not the contaminants from the combustion process that degrades the oil and clogs the filter?

I am a complete non expert, so free forum advice at its best (worst) ………
I would be pragmatic. Most cars have an oil change interval based upon a mix of time and mileage - previously often the time was annual, but to sell more cars to fleets which run only new cars up to 3-4 years old, some manufacturers changed this to up to 2 years (to reduce service costs in first 3 years - most fleets don’t worry thereafter).
Changing oil and filters every 5 months is quick on a time basis. As presumably few cold starts in Turkey, if genuinely using gently and allowing proper warm up before flooring it, I personally would push out somewhere between the 5 months minimum and 12 months as a max.
But they ain’t my engines and I am no tech expert. Personally I do the oil change every 12 months, after 100 to 200 hours - but at the start of winter.
I do the other service items like diesel filters, impellers etc in the spring.

 

[billskip]

OK. But is it not reasonable to assume most of this comes from burning diesel and any metal is more likely at higher revs?

Moisture comes from the air and should mostly be vaporised when the engine is at temperature, carbon comes from the burning of the fuel (and oil lubricant in the bore, metals come from normal wear and tear of the moving parts such as the bearing shells.
Oil will start to deteriorate from the first revolution, some recommended kilometres, hours, and even time in months between services.
It can also be said that during the average ownership some people don't bother with service at all as the problem is sold on to the next owner.

 

[vyv_cox]

Perhaps the largest factor in oil deterioration is acidity. The oil starts off with a certain level of base number, TBN (effectively the opposite of acidity). The combustion process creates weak organic acids, such as carbonic, sulphonic, nitronic and many others that gradually reduce the base number. As acidity increases so does the corrosion of some components, most notably the lead in copper-lead bearings, pretty much universal in diesel engines. Higher revs probably increase the rate of acidity but once the engine is up to normal operating temperature this effect is less noticeable.

So the difference in oil life between a high revving and low revving engine is not a lot. TBN can be measured quite easily by a laboratory, who would advise whether a change is necessary. Whether the cost of the test is more or less than the cost of the oil may be dependent on the capacity of the sump.

 

[rogerthebodger]

The loading on a marine engine in not the same as on a road engine which will also affect the oil life.

Any metal in the oil will show up damage to the engine.

Oil in gearboxes will also have affect due to the lack of carbon but could have metal from and crunched gears

 

[Irish Rover]

Before I move on let me just say my intention is follow the Yanmar schedule unless someone knowledgeable convinces me it's safe and wise to do otherwise. But for those who think servicing is cheap think again. A 250 hour service kit for one of my engines was €600 + VAT so €720. The oil was €120 and the Yanmar service charge is €360 including VAT. So €1,200 x 2 = €2,400 so €500 per month.
And before guys queue up to tell me how easy it is to DIY it's not an option for me. My engines are under the bunks with minimal access, and I'm the wrong side of 70 with arthritis in every joint.