Which Engine Oil Do You Use (& Why)

[Dockhead]

Originally Posted by rognvald

Hannabel,
I would use whatever engine oil is recommended for your engine in case there is a warranty claim or a premature mechanical failure issue. They might be prone to help you if you followed factory recommendations. However, most trucking companies that put millions of miles on their engines use a straight grade oil with a quality filter. Yanmar recommends a straight grade oil in my engine as do most marine mechanics for all engines. I have used straight 30W in the tropics as well as here in the Winter Wonderland. My engine has 2100 hours and when I pulled the head to do my valves, the pistons and cylinders looked literally new with no engine wear. I hope that helps. Good luck and good sailing.

Following the manufacturer's recommendation is extremely good advice. Not just because not doing so might cause a problem with a claim for mechanical failure, but because the manufacturer does not just take the oil grade recommendation out of his hat. Diesel engines are designed for specific types of oil, and if you deviate from that type, you will get results which the manufacturer did not intend.

It is a big, fat fallacy to imagine that the "higher" the grade of oil, the better. "Higher" grades of oil have certain properties which are useful in certain types of engines, but which can be harmful to other types. It would be sort of like saying -- Honda says to use 95 octane gasoline in my Accord. So how much better will it be to use jet fuel? Jet fuel is not better, it's different. Likewise with API numbers.

Marine engines are very different from car engines. Modern car diesel engines are highly stressed devices with high pressure and somtimes even sequential) turbochargers and have very high specific output and a lot of internal heat. Oil temperatures are typically 120C or even more, and the oil is sprayed up on piston heads to cool them and so has to withstand even higher temperatures. They use narrow bearing journals to reduce friction and improve the holy EPA fuel consumption numbers, at the expense of high bearing stresses requiring high film strengths. They are designed to use synthetic oils, and the manufacturers recommend them. I wouldn't use anything but synthetic oil in a car diesel, and I use synthetic in my Range Rover.

But marine engines are totally different -- they have much lower specific outputs and have much lower stressed bearings. They often have seawater cooling of the oil (my Yanmar does) which keeps oil temperature down to 70 - 80 C or even less. The turbochargers -- when used -- are beefy low-pressure things. They have no use for the properties of synthetic oil, and synthetic oil can cause bore glazing, premature wear, and other problems which result from using an oil with too high TBN number:

"Yacht auxiliary engines generally run for short periods, at lower temperatures than any other duty, and typically in the lower half of their rev range. From a lubricant point of view this is a very undemanding duty, accounting for their low API requirement. Combustion temperatures never reach levels at which a high-performance lubricant can be effective, so the overall chemistry in this area is not neutral but alkaline (basic). There is a great deal of evidence to show that use of an oil with a TBN that is too high for the duty can lead to several problems, particularly high wear rates of cylinder bores. The effect of high TBN engine oils in accelerating wear rates is well known. Burning high TBN oils may generate excessive deposits on the piston crown. As the piston tilts when moving up and down these deposits become compressed and will form a very hard and abrasive layer, causing excessive wear, mainly in the bore.

Bore wear has similar detrimental effects as bore glazing, instead of a smooth glaze producing a highly polished surface that leads to poor lubrication and high oil consumption."

Oil for yacht engines

and this:

"A couple of boats ago I had a Prout cat with an almost new but run in Yanmar 2gm in it. We took it on a long delivery trip in a flat calm, so the engine was running at steady revs for about 30 hours. By the time we got there it was drinking oil, never having consumed any beforehand.

Subsequent discussions with both Yanmar technical and the Shell oil laboratories suggested that we had unwittingly committed two sins, the major one being that we had followed the normal idea of being kind to our engine by giving it good oil - a semi synthetic. Yanmar insisted that putting a higher grade modern oil in an old design engine was asking for trouble. I was sceptical so I spoke independently to Shell laboratories and to my surprise they said the same thing. They went so far as to say that we should never use synthetics in old design engines since there were components in the oil that could cause accelerated wear."

That's Bosun Higgs, quoted by Vyv Cox in Oil for yacht engines

So here so you see (a) Vyv Cox, a respected petroleum/lubrication engineer and yachtsman; (b) Yanmar; and (c) Shell -- all saying the same thing:

Don't use synthetic oil in yacht engines.

[sy_gilana]

Any of these that are API CF-2 for our Detroit 3/53

BPVanellus DD 40
BPVanellus MCS 3
CaltexDelo HDD 40
CastrolAssuron 40
Castrol DD 40
GulfSuper DD
LubmarineDisola DD 40
MexlubSAE40 API CF-2/SH
MobilDieselube TLA 40
MobilDelvac 1340
QuepetQuemo DD
ShellRotella DD40 or T40
Sun OilDDC Motor oil
TexacoSeries 5 Extra duty 40 or Ursula T
TotalRubia CF-2

[nhschneider]

Our Beta Marina 90's oil sump holds 13 liters of oil plus another half-liter for the filter. I only carry two oil changes worth of oil on board at any time so that means that I have to buy oil from time to time. Since we've been cruising is some pretty remote places, I have little choice but to buy what's available and have used a wide variety of brands. Fortunately, Beta recommends a 250-hour oil change interval, however, Kubota (the manufacturer of the engine) recommends a 500-hour interval when the engine is installed in its construction equipment. I typically change our oil every 300-400 hours.

When we were still in the USA, I preferred the Delo 400 15W-40 with an API service rating of CF. Our engine now has almost 2,400 hours on it, uses absolutely zero oil between changes and when I pulled the valve cover off recently to adjust the valves, all of the components of the valve train looked brand new.

Fair winds and calm seas.

[Aloha_float]

Shell 15-40 old school - no synthetic
I've been advised by more than one mechanic not to use synthetic


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[Jim Cate]

My engine has 2100 hours and when I pulled the head to do my valves, the pistons and cylinders looked literally new with no engine wear.

Two points here"

1. 2100 hours is hardly broken in, and one would not expect to see worn cylinder walls on such an engine, so this observation doesn't mean much to me.

2. If the engine is in such good shape, why were you having to do the valves?

Not all engine mfgs say to use single weight oil. Our Kubota based Nanni says 15-40, CD, and we have used many brands. Depends on where we are and what is readily available at oil change time (200 hour interval). When one is in the woop-woop, choices are often limited.

Cheers,

Jim

[J Clark H356]

I use the following oil on my Yanmar 1218 hours and 5 KW Northern Lights generator with 2,800 hours.

Yanmar 3GM30F
Valvoline All Fleet Plus for Diesel and Heavy Duty Vehicles -SAE 30 API-CF-4, CF-2, CF/



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[Dulcesuenos]

Originally Posted by Dockhead

Following the manufacturer's recommendation is extremely good advice. Not just because not doing so might cause a problem with a claim for mechanical failure, but because the manufacturer does not just take the oil grade recommendation out of his hat. Diesel engines are designed for specific types of oil, and if you deviate from that type, you will get results which the manufacturer did not intend.

It is a big, fat fallacy to imagine that the "higher" the grade of oil, the better. "Higher" grades of oil have certain properties which are useful in certain types of engines, but which can be harmful to other types. It would be sort of like saying -- Honda says to use 95 octane gasoline in my Accord. So how much better will it be to use jet fuel? Jet fuel is not better, it's different. Likewise with API numbers.

Marine engines are very different from car engines. Modern car diesel engines are highly stressed devices with high pressure and somtimes even sequential) turbochargers and have very high specific output and a lot of internal heat. Oil temperatures are typically 120C or even more, and the oil is sprayed up on piston heads to cool them and so has to withstand even higher temperatures. They use narrow bearing journals to reduce friction and improve the holy EPA fuel consumption numbers, at the expense of high bearing stresses requiring high film strengths. They are designed to use synthetic oils, and the manufacturers recommend them. I wouldn't use anything but synthetic oil in a car diesel, and I use synthetic in my Range Rover.

But marine engines are totally different -- they have much lower specific outputs and have much lower stressed bearings. They often have seawater cooling of the oil (my Yanmar does) which keeps oil temperature down to 70 - 80 C or even less. The turbochargers -- when used -- are beefy low-pressure things. They have no use for the properties of synthetic oil, and synthetic oil can cause bore glazing, premature wear, and other problems which result from using an oil with too high TBN number:

"Yacht auxiliary engines generally run for short periods, at lower temperatures than any other duty, and typically in the lower half of their rev range. From a lubricant point of view this is a very undemanding duty, accounting for their low API requirement. Combustion temperatures never reach levels at which a high-performance lubricant can be effective, so the overall chemistry in this area is not neutral but alkaline (basic). There is a great deal of evidence to show that use of an oil with a TBN that is too high for the duty can lead to several problems, particularly high wear rates of cylinder bores. The effect of high TBN engine oils in accelerating wear rates is well known. Burning high TBN oils may generate excessive deposits on the piston crown. As the piston tilts when moving up and down these deposits become compressed and will form a very hard and abrasive layer, causing excessive wear, mainly in the bore.

Bore wear has similar detrimental effects as bore glazing, instead of a smooth glaze producing a highly polished surface that leads to poor lubrication and high oil consumption."

Oil for yacht engines

and this:

"A couple of boats ago I had a Prout cat with an almost new but run in Yanmar 2gm in it. We took it on a long delivery trip in a flat calm, so the engine was running at steady revs for about 30 hours. By the time we got there it was drinking oil, never having consumed any beforehand.

Subsequent discussions with both Yanmar technical and the Shell oil laboratories suggested that we had unwittingly committed two sins, the major one being that we had followed the normal idea of being kind to our engine by giving it good oil - a semi synthetic. Yanmar insisted that putting a higher grade modern oil in an old design engine was asking for trouble. I was sceptical so I spoke independently to Shell laboratories and to my surprise they said the same thing. They went so far as to say that we should never use synthetics in old design engines since there were components in the oil that could cause accelerated wear."

That's Bosun Higgs, quoted by Vyv Cox in Oil for yacht engines

So here so you see (a) Vyv Cox, a respected petroleum/lubrication engineer and yachtsman; (b) Yanmar; and (c) Shell -- all saying the same thing:

Don't use synthetic oil in yacht engines.

I posed this to the engineers at Shell oil co/ Westhollow lab,, and they say This is wrong, TBN or total base number is the active ingredient in motor oil, and a high TBN will in no way lead to the wear reported here. Their Rotella does have a high TBN even their Conventionals, if what you posted were true there would be a ton of sailboat diesels out there needing repair.

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[ranger58sb]

Originally Posted by Wotname

What engine oil (mineral, semi- synthetic, full synthetic) and API rating do you use (for small yacht diesel engine like Yanmar, Volvo, Bukh etc)?

Dinosaur, weight recommended by engine and manufacturers, with the newest diesel API rating (which exceeds the original recommended rating in a couple cases).

Our mains are not small yacht engines, though. OTOH, our genset engine is about the same as a small yacht diesel. As is the diesel in our tractor at home.

-Chris

[Dockhead]

Originally Posted by Dulcesuenos

I posed this to the engineers at Shell oil co/ Westhollow lab,, and they say This is wrong, TBN or total base number is the active ingredient in motor oil, and a high TBN will in no way lead to the wear reported here. Their Rotella does have a high TBN even their Conventionals, if what you posted were true there would be a ton of sailboat diesels out there needing repair.

Sorry, but this is all wrong. TBN is not the "active ingredient in motor oil", it is the measure of how alkaline the oil is. Motor oil is made more alkaline with additives in order to neutralize acids which form in the combustion process. "Higher" grades of motor oil, designed for longer change intervals -- or to be exact, designed for engines with extended oil change intervals according to the manufacturer's recommendations -- have more of the additive which makes them more alkaline.

It is well-accepted that too much of these additives cause premature wear. For example:

"[T]he additives responsible for this excess in base [that is, alkalinity] will be burnt in the combustion chamber, resulting in the formation of a thick layer of ash on the piston top land. This could eventually interrupt the oil film and promote abrasive polishing of the [cylinder] liner surface and ring/liner scuffing." Pounder's Marine Diesel Engines and Gas Turbines, page 129.

Just about exactly what Vyv Cox said in his website.

As to whether or not there are a ton of sailboat engines needing repair -- why, there are. Sailboat engines have, on the average, far shorter lifetimes than other diesel engines. It is common to see sailboat diesel engines needing an overhaul with less than 1000 hours on the clock, and 5,000 or 6,000 is considered really good, whereas diesel engines in trucks and construction equipment routinely go for tens and tens of thousands of hours. This short life is probably not mostly from people using the wrong oil, but it sure doesn't help.

"Higher" grade oil is made for more highly stressed engines, and the other design goal of "higher" grade oil is to make long change intervals possible (for example, high TBN allowing the oil to absorb a lot of acid before it needs to be changed). These are properties which are totally unnecessary in sailboat engines, which are very low stress compared to diesel car engines, which run with much cooler combustion chambers, and which don't need to go many hundreds of hours between changes, because we have to change the oil anyway because of the time-limitation on oil changes.

"Higher" grade oil is not better in general -- it is only better for a particular type of service. It so happens that this type of service is totally different from what our engines do.


Getting back to the OP's question -- which oil do I use -- my Yanmar 4JH3 HTE is supposed to have API CD oil which is almost impossible to get anymore. The recommended substitute is CF4, but this is rather different from CD which makes me nervous. So I use the overpriced Yanmar oil, mostly, or cheap CF4 if I can't get the Yanmar oil. I change it often -- usually at 100 hours. Never more than 200.

[Dulcesuenos]

The "active ingredient" is not a tech term but does describe tbn, it is its ability to combat acids, when its depleted or too low the engines parts ar at risk as is the lubricating properties of the oil. Everyone is entitled to believe anything they want to, just like whats the best anchor. Oil technology is like the medical field. What they thought was right one year is proved wrong 10 years later. Just like something's were thought bad, and now they are healthy. Go with whatever makes you feel good and believe whatever feels good lol.

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[sy_gilana]

Originally Posted by Dockhead

Sorry, but this is all wrong. TBN is not the "active ingredient in motor oil", it is the measure of how alkaline the oil is.

Agree with Dockhead.

Our Detroit has 4100 hours, never been opened, oil change every 150 hours.
Our Onan has just shy of 17,711 hours Oil change at 200 hours.

We use the same oil on the Onan, but we have a larger volume oil filter and it takes about 750ml more so that might help too.

[dannc]

Ah, Oil. Right up there with anchors and guns.

Follow the manual. Its that simple.

Ok, no it is not.

I have had three diesel engines and still have two. The manual was pretty much the same for all three. Currently I have a JD tractor which has a Yanmar engine and a Ford truck with an International engine.

Neither manual mentions 5Wx40 oil but I have used the oil in both engines. Oh No! I must be destroying the engine! Ah, no. The 5 of 5Wx40 lets allows a lower temperature when operating the engine. 40 weight allows the engine to operate at a higher temperature. Not rocket science.

Both engines have run 15Wx40, 5Wx40 and 0Wx40 oil. Currently I am using the JD 0Wx40 oil, which is a synthetic because it was cheaper to buy in the past than the 5Wx40 semi synthetic oil from Shell. I run the 5Wx40 or 0Wx40 oil because I run extended change periods on the truck and tractor, these oils start MUCH better in cold weather, and do provide a slight MPG improvement.

I just looked at the manual for the engine we would have in the boat we want. The manual looks just like my tractor and truck manual in regards to oil except it actually mentions 0Wx40 oil. JD does not care if you use synthetic or regular oil.

The JD 0Wx40 had/has a very high TBN though I have read TBN levels have been reduced due to the lower sulfur levels in fuel. I do UOA on my truck and tractor engines and they both have VERY low wear even with extended drain times. I have done this for years and the lab has a large data base to compare my truck engine against. Not so much with the Yanmar but that engine has very low numbers and does not use oil at all. Amazing engine.

Not sure what I would run in the boat. Given the first year or so would be in a warm climate, I doubt I would run a synthetic 0/5Wx40 oil. But the oil would be a 40 weight oil since the upper temperature range is 122 degrees. Kinda would like to have a higher temp range than 122. A 15Wx40 oil would be fine for that environment.

Interestingly, JD does not specify a single weight oil for the engine which makes sense to me.

Later,
Dan

[rognvald]

Very good discussion! To respond to a few concerns about oil without writing a scientific paper, there is one real concern for using a straight weight oil versus a multi-grade namely, a straight weight oil is developed for a specific usage and temperature range whereas a multi-grade oil is used for a widely varying temperature range. Most straight 30W oils have a range between 68-95 degrees Fahrenheit. This means that if your engine operates in this general temperature range, the straight weight oil will provide the greatest protection for lubrication, cooling, sealing, and cleaning. Whether in Northern Illinois or the Tropics, a straight 30W is the ideal oil for my engine since the ambient temperature rarely is below or above the recommended range. However, in regards to a multi-grade oil --say, 10W30 the oil(due to additives that "transform" the oil) has the ability to operate in much lower/higher temperatures with the disadvantage that as the oil degrades over time it will not provide the same protection at higher/lower temperatures to the top and bottom of the engine that a straight grade oil will provide. Look at it like the difference between a specialist and a generalist. So, many engine manufacturers recommend these oils since they assume it will provide "adequate" protection wherever the boat is located/sailed and assumes the operator knows little or nothing about engine oils-- which is usually the case. It's your engine, it's your money, it's your choice. Finally in regards to Jim Cate's questions concerning my engine. The reason I pulled the head on my engine at 2000 hours is that after replacing my injectors(maintenance) and rebuilding my injection pump(to solve a problem), the engine was still starting hard and not running properly at low RPM's. After replacing the head, I discovered that the company who rebuilt my injection pump did not do it properly and after it was rebuilt a second time the engine ran perfectly. In regards to concern over engine wear, when one buys a used boat you never really know what the maintenance schedule was before you bought it. If the PO did infrequent oil changes, ran the engine on low oil, didn't clean the mixing elbow or heat exchanger, used poor quality or incorrect oil ,it is very possible in much less than 2000 hours to have scored cylinder walls, worn bearings, and worn rings. It is my general observation in the last 25 years that there are many who own sailboats who are good sailors but few who know even the most essential basics of good engine and mechanical maintenance of their vessels. I hope this is clear. Good luck and good sailing.

[BandB]

Originally Posted by Dockhead

Yanmar insisted that putting a higher grade modern oil in an old design engine was asking for trouble. I was sceptical so I spoke independently to Shell laboratories and to my surprise they said the same thing. They went so far as to say that we should never use synthetics in old design engines since there were components in the oil that could cause accelerated wear."

Don't use synthetic oil in yacht engines.

Those two statements are not the same. You quote Yanmar and Shell as saying not to use it in old design engines. They you say not to use it in yacht engines (regardless of new or old design).

I go back to manufacturer's recommendation. These are just from manuals I have close.

On current model (common rail) engines, MTU lists many synthetics among their recommendations.

For MAN common rail engines, they recommend synthetic oils, but only one manufactured in the US is on their list or was at one time. Delvac1 5W-40

Lugger simply says a. API Service CC/CD single viscosity oils. b. API Service CC/CD/SF multi-viscosity oils.

Kohler recommends not using synthetic the first 50 hours and then has different change intervals.

There are many factors and I just trust those who should know and those who would have to cover any problems under warranty.

Of course they all have their own labeled products too. Yanmar is really big on pushing their oil. And we actually use MTU's. Yanmar 4BY and 6BY use synthetic only.

So that's why broad statements can get us in trouble.

[zeehag]

i USED to use rotella or delo which ever i could find on shelves where i cruise..and 40 wt.
then i suffered runaway diesel and the repairing of the changes from that incident are still in final stages.
i will be using whatever my remanufacturer says i need to use, and he will tell me in spanish. ok.. i know it wont be a brand specific named oil, and i hold no oil snobbery.
i donot purchase the cheaper non detergent oils unless specifically required in my engines.