Oil Change Schedule

Changing oil annually, and I don't worry about oil. Undoubtedly, the engine (being 64 years younger) will outlast me.

sunchaser said:

As said early on in this thread by many, yes go by your BOOK

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But how many times will we have to repeat that? Probably thousands if we live long enough.

My engine (TAMD40B Volvo) manual says to change oil every 100 hrs., filter every other oil change. It has a tachometer with an digital hour meter encased inside it. I also have a separate hobbs type hour meter wired to the motor. When the tach hour meter shows a 100 hr interval, the hobbs hour meter will show 200 or more hours on it. My mechanic says that the volvo meter is measuring the RPM and run time (working/load time) and that is what I should go with for the oil change. So thats what I do. Sounds good, wouldn't think they would have done that back in '83. 1750+ on the hobbs meter and 755+ on the Volvo meter. Go figure.

ddalme said:

My engine (TAMD40B Volvo) manual says to change oil every 100 hrs., filter every other oil change. It has a tachometer with an digital hour meter encased inside it. I also have a separate hobbs type hour meter wired to the motor. When the tach hour meter shows a 100 hr interval, the hobbs hour meter will show 200 or more hours on it. My mechanic says that the volvo meter is measuring the RPM and run time (working/load time) and that is what I should go with for the oil change. So thats what I do. Sounds good, wouldn't think they would have done that back in '83. 1750+ on the hobbs meter and 755+ on the Volvo meter. Go figure.

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If the Hobbs is making you change every 50 hours, I'm not so sure I'd go with that. I'd talk directly to Volvo. On the other hand, it's not going to hurt anything. He's right that fuel flow is actually what manufacturers would prefer to use. It's an indication of how much and how hard an engine has been run. However, it really only is needed in higher hp engines and even there the manufacturers have taken it into consideration on their recommendations. Only if you subject it to significantly harder use does it generally require more than the manufacturers recommendation.

ddalme said:

My engine (TAMD40B Volvo) manual says to change oil every 100 hrs., filter every other oil change. It has a tachometer with an digital hour meter encased inside it.

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I never understood not changing a filter when the oil is changed. Not that it is a bad idea, but if I am gong to go to the trouble of changing my oil, I am going to change the filter as well. It is cheap.

Of course, I only have a small 56hp Yanmar and changing the oil is a major PITA. I have never used an oil change system. Maybe that would change my perspective?

Isn't the rat race that starts this whole crazy thread?


It never hurts to change early and while we are at it, compared to boating in general...why don't we change oil filters, fuel filters, tranny oil, belts, hoses...etc...etc????

Do recommendations always mention filters when oil is changed?

Of course you can change things before the "book" cycle and because it is cheap and for some easy....but all the way back to the OP...


Changing before recommended intervals if everything is IAW manufacturer recommendations and usage and calendar are correct...well for some of us IS a complete waste of time, energy and money that is better spent elsewhere.


If someone can show without a doubt changing early actually lengthens life...I might and maybe others will consider...till then...yes on sked if usage is as recommended with no overheats, dusty conditions, etc....and an oil that meets spec.


Ya wanna do it early fine...but no one has convinced me that oil is as big a deal as some make it. Besides manufacturer recommendations...there are lots of examples of just how tolerant the engines are....but stick to the sked as recommended if you can.

dhays said:

I never understood not changing a filter when the oil is changed. Not that it is a bad idea, but if I am gong to go to the trouble of changing my oil, I am going to change the filter as well. It is cheap.

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We never understood that on cars. First, we never bought in to dealers telling us we needed to change more frequently than the manufacturer did. Manual says 7,500 miles and dealer wants to do 3,000. No thanks. But then we always changed filters when we changed the oil.

Now, my manufacturer says 12,500 miles or annually. As I only average 4,000 miles a year, annually it is.

The difference with cars and boat engine manuals that I have read...


Car manuals have caveats for oil changes...ideally XXXXX, if stop and go YYYYYY, if dusty environment ZZZZZZ.


So why not marine engines? That's why people who run these day in and out often have to question manufacturers and engineers...but most of the time follow the recommended for warranty or lack of better info.

I'm pleased to see high authorities recommending oil changes w/o filter changes. I reason that most all of the carbon gets taken out of the engine and if oil changes are more frequent than recommended or what's considered normal the filter has much more capacity for more filtering.

Many here put vacuum gauges on their fuel filters to know when the filter is beginning to get plugged and in need to be change. If one did that on oil filters they may get 30 or more oil changes per filter change. Millions of good filters are getting thrown away every day.

Changing filters is both time and money conservative but just changing the oil seems an easier job and I'm much more likely to do it that way. But certainly it makes little difference.

any links to when filters should be changed?

ddalme"My engine (TAMD40B Volvo) manual says to change oil every 100 hrs., filter every other oil change. It has a tachometer with an digital hour meter encased inside it. I also have a separate hobbs type hour meter wired to the motor. When the tach hour meter shows a 100 hr interval, the hobbs hour meter will show 200 or more hours on it. My mechanic says that the volvo meter is measuring the RPM and run time (working/load time) and that is what I should go with for the oil change. So thats what I do. Sounds good, wouldn't think they would have done that back in '83. 1750+ on the hobbs meter and 755+ on the Volvo meter. Go figure."

I have both Hobbs and Volvo hour meters. I had TMD40s, that had only the Hobbs. I upgraded to TAMD41 that came with a meter in the tach. I connected that to the ignition wire that had previously been connected to the Hobbs meter, and it records time that the ignition is on, not according to the rpm of the engine.
How are yours connected? Since I have both, could I connect mine as yours are connected? Could you change yours over to the way mine are connected?
Yours certainly have implications on engine longevity. This is something you may want to change before you sell. Or not!

Trundlebug said:

I always change my oil in the autumn, just before the boat gets left for several months over the winter. It's essential it has fresh oil in it for this period because if it had, for want of a better expression stale oil (used) the acidic components can eat into the bearing shells whilst it's sitting stationary over the winter, potentially leading to early (or earlier) bearing wear. The wear factor isn't necessarily the only major problem - it's the acidity and other factors.

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I do concur, it's the fact that we age our boats, and the fluids within, more than wear them out (like humans). My Audi car manual warns me to use synthetic oil because it "is thinner on starts" and prevents scoring, but my DD 8.2's bump and run almost on contact, so I don't worry. And diesel No. 1 might have lubricants - I light one candle.

OTOH, since I am building filthy fires in my engine block, it behooves me to put out the ashes asap, lest we have chimney fires..my last words will be (when an ancient 8.2L cashes out) a boater's moral lament:

"I did all that I could.."

-Dwight

Koliver
Now you got me thinking that I need to see how the Volvo tach hour meter is wired. Next time I'm released to go(babysitting my wife-knee replacement) to the boat, I'll report.

This is a little off the mark, but to the extreme none of us have seen. I had a tech that drove his gas engine van 31,000 miles and only added oil when it was low. When the engine quit moving the mechanic took the oil out of the pan with a metal scraper.

ddalme said:

Koliver

Now you got me thinking that I need to see how the Volvo tach hour meter is wired. Next time I'm released to go(babysitting my wife-knee replacement) to the boat, I'll report.

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Me too. The digital meters are blank and the PO put (I assume) Hobbs meters in there. Ran then on his lawnmower battery until they matched the digitals. Well... Add it to the list I guess.

Caltexflanc,

Thanks for the link. Other articles that link from this one, especially horsepower are interesting. If I have understood the article correctly, on my boat it does not matter if I have a 400 hp engine or 600 hp engine I will burn the same fuel amount at 7 1/2 kn. I have argued this point with the experts on the dock, and they don't seem to understand that it takes a certain amount of power to move a given weight of boat through the water. It only means that a larger engine has to work less hard.

Gordon

"It only means that a larger engine has to work less hard."

The less hard most diesels work the less efficient their BMEP becomes.

It can be a 10%- 30+% difference in fuel per HP.

A larger engine will have more and heavier parts thrashing about , all cost energy to start and stop, and keep lubricated and cool.

Bigger boil pump, bigger water pump, and larger bearings eating HP , no free lunch..

And then there is Slobbering from long term underloading.

koliver said:

ddalme"My engine (TAMD40B Volvo) manual says to change oil every 100 hrs., filter every other oil change. It has a tachometer with an digital hour meter encased inside it. I also have a separate hobbs type hour meter wired to the motor. When the tach hour meter shows a 100 hr interval, the hobbs hour meter will show 200 or more hours on it. My mechanic says that the volvo meter is measuring the RPM and run time (working/load time) and that is what I should go with for the oil change. So thats what I do. Sounds good, wouldn't think they would have done that back in '83. 1750+ on the hobbs meter and 755+ on the Volvo meter. Go figure."

I have both Hobbs and Volvo hour meters. I had TMD40s, that had only the Hobbs. I upgraded to TAMD41 that came with a meter in the tach. I connected that to the ignition wire that had previously been connected to the Hobbs meter, and it records time that the ignition is on, not according to the rpm of the engine.
How are yours connected? Since I have both, could I connect mine as yours are connected? Could you change yours over to the way mine are connected?
Yours certainly have implications on engine longevity. This is something you may want to change before you sell. Or not!

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Ck'd yesterday and my tach has a sending wire from engine and a ground and a 12 volt?? to the key switch-so I'm thinking that the hr meter adjustments must be internal. I'm going to time run time with a stop watch and see if I can get an idea of the variation of times between the tach hr meter and the hobbs meter at say 1600 RPM. I'll report back.

Gordon J said:

Caltexflanc,

If I have understood the article correctly, on my boat it does not matter if I have a 400 hp engine or 600 hp engine I will burn the same fuel amount at 7 1/2 kn. I have argued this point with the experts on the dock, and they don't seem to understand that it takes a certain amount of power to move a given weight of boat through the water. It only means that a larger engine has to work less hard.

Gordon

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Generalities such as this are always dangerous and seldom hold true across the board. Engines even of the same hp can be set up very differently. Then you take a 400 hp and a 600 hp and so much depends on how they are tuned to run most efficiently. I've looked at hundreds, if not thousands, of performance charts and the more I look at the more I realize that each has to be considered on it's own.

I have charts in front of me on one boat of two engine choices. The larger hp gets better fuel economy at every low speed than the smaller one. Now these come from the same basic block. However at each speed the lesser hp is turning more rpm to achieve the same speed and is less efficient. Then I'm looking at two planing hulls, two different boats. The smaller but faster boat with the smaller engine is tuned in such a way that it has no slow speed economical level. The other boat doesn't achieve the top end but at slow speeds is far more efficient with the larger engine.

The reality is that I can achieve any amount of hp many different ways. Each of those ways is going to use a different amount of fuel. Therefore, making any assumption as to their efficiency at a given speed, without knowing the specifics may be wrong.

The other place we err is in comparing boats. We act sometimes as if two outwardly similar boats have identical hulls and performance. They don't. Even take two "full displacement hulls" and it's not true. They aren't identical.

Some of these general statements may be useful. However, don't take them to the bank.

BandB,

Yes I was making a general statement, but was thinking that a 200 hp engine and a 300 hp may be essentially the same size, but the additional turbos give the engine greater oomph (technical term). I guess what I was getting at is a friend has an identical boat to mine, but has twin Cat NA 210 horsepower engines. He claims he will get better fuel economy than turbo charged cummins 6BTA. Everything I have read says it takes same amount of energy to propel boat at same speed.

But, perhaps that is pure physics and doesn't hold true in the real world, because of the other considerations. Because I haven't closed on the boat yet, we survey next week, I won't know for some time.

How many of you use fuel scan to track instantaneous consumption?

Gordon

BandB,

Yes I was making a general statement, but was thinking that a 200 hp engine and a 300 hp may be essentially the same size, but the additional turbos give the engine greater oomph (technical term). I guess what I was getting at is a friend has an identical boat to mine, but has twin Cat NA 210 horsepower engines. He claims he will get better fuel economy than turbo charged cummins 6BTA. Everything I have read says it takes same amount of energy to propel boat at same speed.

But, perhaps that is pure physics and doesn't hold true in the real world, because of the other considerations. Because I haven't closed on the boat yet, we survey next week, I won't know for some time.

How many of you use fuel scan to track instantaneous consumption?

Gordon

Gordon J said:

I guess what I was getting at is a friend has an identical boat to mine, but has twin Cat NA 210 horsepower engines. He claims he will get better fuel economy than turbo charged cummins 6BTA. Everything I have read says it takes same amount of energy to propel boat at same speed.

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Same amount of energy, but no two engines produce that energy the same. One way do so more efficiently than the other. Plus we're talking engine hp on much of this and hp at the propeller is what is more important. Even then you have alternatives among props to achieve different results. Just so many factors. His claim may well be true at certain speeds. I have no idea. I'd have to see actual data before I'd speculate.

BandB wrote on post # 79;
"I have charts in front of me on one boat of two engine choices. The larger hp gets better fuel economy at every low speed than the smaller one. Now these come from the same basic block. However at each speed the lesser hp is turning more rpm to achieve the same speed and is less efficient. Then I'm looking at two planing hulls, two different boats. The smaller but faster boat with the smaller engine is tuned in such a way that it has no slow speed economical level. The other boat doesn't achieve the top end but at slow speeds is far more efficient with the larger engine."

It would seem to me the smaller engine should be more efficient if not the smaller engine w higher rpm. Big cylinders are a heat sink and heat loss is very bad for efficiency. There of course there are many variables and the domino effect could skew one example not in the normal direction.

manyboats said:

It would seem to me the smaller engine should be more efficient if not the smaller engine w higher rpm. Big cylinders are a heat sink and heat loss is very bad for efficiency. There of course there are many variables and the domino effect could skew one example not in the normal direction.

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Well, I've seen examples in all types of boats but let me give you a specific example I have in front of me. I recognize it's not in full displacement boats.

Boat A, 65' Flybridge. 1000 hp MAN's or 1200 hp MAN's. The 1000 hp requires 1200 RPM to achieve 10 knots and does so at 0.6 nmpg. The 1200 hp requires 900 RPM to achieve 10 knots and does so at 0.93 nmpg. In fact, the 1200 hp is more efficient at all speeds, from 9 knots to 28 knots.

Boat B is a 44' open boat from another builder. 800 hp MAN's. At 10 knots it is turning 900 RPM and doing so at 0.8 nmpg. The unique thing about Boat B is that it gets 0.6 nmpg at 40 knots and just has a very gradual curve.

Actually Boat C from the same builder as Boat B has 1360 hp MAN's. It is similar in that it's curve is very slight. At 10 knots it gets 0.44 nmpg. At 40 knots it gets 0.30 nmpg.

At WOT however, Boats B and C both get better mileage than Boat A which only gets 0.25 nmpg. Should note that the engines in Boat A are both 8 cylinder. The engine in Boat B is a 6 cylinder and Boat C is a 12 cylinder.

These are all engines from the same manufacturer. However, different boat builders. Clearly the builder of B and C is interested in the top of the range while builder A is interested in lesser cruising speeds.

The only point here really is that things may not be as you'd expect. Just don't assume or go by what somebody said. See if the builder or a former seller of the boats has any performance charts.

Ahhhhhh...actually designing a boat with power plant(s) in mind...what a concept!!!

BandB,
Haha I knew you'd come up w something. Good job.
Sometime (mid 90's ?) big trucks seemed to get much more powerful and do it at considerably lower rpm. I suspect that had a lot to do w turbochargers and electronics.
I know it often goes the other way but you can't get around basic physics and all these engines are "heat engines" .... they make power from heat and heat loss is probably directly porportional to power loss. And of course some engines make better power than average at lower rpm and the reverse is (I believe) more often true. But there are many variables ...... and things often aren't as we expect.

You could make my small Mitsu make as much power as a Ford Lehman and w much lower heat loss most likely more efficient. However turbocharging would probably be necessary and the increased swept volume of air going through the engine would be increased heat loos as well ... that would be combined w the cyl surface area and combustion chamber loss. The total increased swept volume may make the little engine less efficient. Then there's the size of the cylinders v/s the # of cylinders ect ect. Interesting stuff but it usually leads one off into the fog.

manyboats said:

Haha I knew you'd come up w something. .

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My advantage is I know nothing about engines. Nothing about the science. No idea how they do what they do. So, I can't get into the theory. What I have looked at over time is a lot of tests, a lot of data, on a lot of different boats. Sometimes the data seems to contradict conventional logic. So, for me, it's no labs, only real boats.

Sometimes ignorance is dangerous and sometimes bliss. Going back to the original question, we do oil change and all maintenance by the owner's manual or sooner if the trip we're ready to take would lead us past the due period. I know, from what others had said and the oil analyses, that we could probably go longer with no damage. I just choose not to. First, for warranty purposes. Then, simply because going by the manual has worked so well for me during the last 30 years or so.

Pgitug wrote;
"This is a little off the mark, but to the extreme none of us have seen. I had a tech that drove his gas engine van 31,000 miles and only added oil when it was low. When the engine quit moving the mechanic took the oil out of the pan with a metal scraper."

This seems far fectched. Perhaps your "tec" was pulling your leg or chain?

However it opens the door to wondering how far a road vehicle could go w/o changing the full flow filter. If the oil stopped flowing one would'nt be very interested in changing oil. A road vehicle would fill it's oil filter much faster than a boat I would think. That adds to the notion that I have of the filter not needing replacement nearly as often as the oil. When I was a young man some of our old heaps burned/leaked so much oil that we never drained it assuming we were constantly changing oil. And we had by-pass filters.

On the opposite end of oil-change schedules...

I was looking at the boat the other day. A bit under 800 hours on the engine over 6 years. The original owner has had the oil changed 2 to 3 times during that entire time! At first I thought I simply misunderstood him. Nope.

I agree with "By the Book" in all pleasure boat applications. The savings in trying to extend oil life is not worth the risk of long term damage. And that is what its about - risk vs reward.

I used to work as operations manager for a company that had a fleet of many hundreds of Caterpillar 3516 generators. In this application, lubricating oil was one of our biggest operating costs. We extended the recommended oil life significantly, but took oil samples on engines daily towards the end of the oil life. In many cases we were able to get double the hours compared to "the book", but this varied considerably depending on many other factors.
A pleasure boat is a completely different story.