Which Engine Oil Do You Use (& Why)

[J Clark H356]

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[Tx J]

Arrrrr mateys, I be usin’ strrrate 50W wid me ol’ delltaa ahnkrrr, but I goannaa swich ta’ t’ fanci muultee blenndd 15x40W sintetic fer me neuw Rōcnna ahnkrrr...

[Wotname]

Originally Posted by ranger42c

I think folks can look up some oil factoids. See Service Categories (with emphasis added, ref diesel categories):

API Engine Oil Service Categories

The current and previous API Service Categories are summarized in convenient charts. Vehicle owners should refer to their owner's manuals before consulting these charts. Oils may have more than one performance level. For automotive gasoline engines, the latest engine oil service category includes the performance properties of each earlier category. If an automotive owner's manual calls for an API SJ or SL oil, an API SM oil will provide full protection. For diesel engines, the latest category usually - but not always - includes the performance properties of an earlier category. Service Category API CJ-4 describes oils for use in high-speed four-stroke cycle diesel engines designed to meet 2007 model year on-highway exhaust emission standards as well as for previous model years. These oils are especially effective at sustaining emission control system durability where particulate filters and other advanced aftertreatment systems are used. For more information on API CJ-4 including frequently asked questions, please visit CJ-4 WEBSITE.

Sorry, I can't agree...

While I'm sure your extract reflects the truth for automobile gasoline engines and even for some modern diesel auto engines, there is simply no facts here pertaining to 30+ year old cold running small marine engines.

For instance, TBN figures are considerably different between various diesel oils and there is sufficient speculation that this in itself can cause damage.

[ranger58sb]

Originally Posted by Wotname

Sorry, I can't agree...

While I'm sure your extract reflects the truth for automobile gasoline engines and even for some modern diesel auto engines, there is simply no facts here pertaining to 30+ year old cold running small marine engines.

For instance, TBN figures are considerably different between various diesel oils and there is sufficient speculation that this in itself can cause damage.

OK, in that case, I guess your disagreement is with api.org...

In any case, my impression is that folks can look up each service category on that site, to learn and then consider various performance properties associated with each.

-Chris

[Snowpetrel]

For whats its worth, after considerable research, that I've mostly now forgotten... I went with a cheap Top dog oil from Autobarn in Hobart. It was one of the few oils that had a cf 4 rating and a lowish TBN of 8. And its cheap enough that I can justify very regular oil changes. I couldn't find anything with a CD rating locally so hopefully this will do the trick for my old kubota based engine. I had more problems deciding what coolant to use!

http://www.gulfwestern.com.au/Data%2...-40-3-2014.pdf

and

http://www.autobarn.com.au/engine-oi...5w40-10l-31012

[rwidman]

The KISS principle (Keep It Simple, Stupid) tells us that the manufacturer of our engine is in the best position to specify what oil to use in it and how often to change it.

So, rather than trying to out research the manufacturer, just use what they recommend and replace it when they recommend replacing it. That leaves more spare time to do fun things.

[a64pilot]

Anyone gone over to bobistheoilguy.com and run this up over there?

I have a 27 yr old Yanmar 4JHE, I run the pure syn version of Rotella, Shell Rotella® Products - Shell Rotella I buy into it's a "better" oil, largely due to corrosion resistance as my engine isn't run as often as if it were a power boat. Viscosity with Syn oils is different, viscosity improvers that have to be put into regular oils may not have to be used in Syn oils.

I feel pretty strongly, especially for older engines that a straight weight, decent quality oil may be the best thing as one of the first of the additive packages that break down in oil is the viscosity improvers.

Vast majority of the time your changing Diesel oil not because it's broken down, but because it's laden with soot and this soot is abrasive, leads to maybe a by-pass flitration system? But heck I'm a sail boat, I'd rather spend that money somewhere else.

Personal opinion, oil wise best thing you can do is change it often and on a schedule, take calender time in account too, not just operating hours. Oil is at it's best just when it comes out of the can, from that point on it begins to degrade, you pick how far before it's changed.

Regular, frequent oil changes are far more important than oil type or brand for engine longevity.

[Dulcesuenos]

Its funny that the believers of high tbn causes damage is based on one persons experience that they documented how long ago??? Even though current lubricant engineers/ scientists say otherwise.

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[Snowpetrel]

A maintenance superintendent of a landfill gas burning power plant contacted us some time ago and asked about engine oil base numbers. He figured you can never have enough protection.

Q: Use of a higher base number (BN) oil if you can afford it. Is this a good way to maintain your engines?

A: No. You can actually destroy an engine solely by using a higher than needed base number engine lubricating oil. Total base number (TBN or BN) is a measure of the reserve alkalinity additive present in the oil. It is designed to neutralize harmful acids produced as the byproducts of engine blowby. What many engine owners don’t often realize is that the strength of this alkaline reserve package is tailored to the sulfur content in the fuel. It is not uncommon to see high levels of sulfur in large marine, landfill, or power generation applications, and as such high TBN oils must be used to combat the highly corrosive blowby gases entering the crankcase. Whereas most users understand and use the higher TBN oils for these sour fuels, if your sulfur content decreases, you must decrease your TBN number also. The following example illustrates the danger of not doing so.

Several years ago, a large reciprocating engine plant serving several Boston hospitals ran into this problem 1. The situation occurred when they were changing lubricants, and the suggestion at the time was to use a high detergency 24 TBN oil, even though their No. 6 fuel oil sulfur content remained at or below 0.5%. The cleaner blowby gases resulted in more alkaline reserve additives remaining in the oil. In the presence of water, these excess carbonates recrystallize to form larger particles, which in turn are carried to cylinder walls. A reaction with combustion gases occurs here, producing calcium sulfates. These products cling tenaciously to the cylinder walls, and look like a slate/stone like deposit (known as slating or furring). These deposits are very abrasive, and promote bore polishing, eventually leading to piston seizure.

The current efforts to use cleaner, low sulfur fuels nowadays means that engine owners need to consult their lube supplier when the fuel properties change substantially, so as to recommend the right matching lubricant. Make sure to analyze your engine oil properly on a frequent basis.

-DPW

1: Seifert, W., Westcott, V. Santoro, S., “Systemic Evaluation- An Integrated Approach to Machine Condition Monitoring”, P/PM technology, Vol 5, Issue 1 pp 17.

......

[Blue Crab]

My dad, James "Big Jimmy" Crab was rarely incorrect on his advice to me as a young peeler. On oil for any machinery, his advice was "keep using the same oil the engine has always used." When I acquired my 2GM20F with 500 hours, the PO, a diesel mechanic for Gregory Poole (big diesel outfit) suggested I continue using Rotella T 15W-40, CJ-4 ... . My thought was why wouldn't I?

The water temps here on East coast US run from about 10+ C° to occasionally close to 32C°.

A short blurb from the J-30 site: Note: Oil Viscosity should be as recommended in Yanmar Service Manual for outside temperature ranges – SAE 10W-30 will cover you for most of North America for year round use. If the water temperature is above 95 degrees, use 50W oil. The service grade should be SAE CB or CC for moderate duty diesel engine service.

From the Yanmar Manual:
Choose a lube oil with a rating higher than SAE class CC.
3) Lube oil viscosity ... The lube oil weight number chosen should vary with the season and temperature.
4) Recommended brands of lube oil for crankcase:

Below 10C 10-20C 20-35C Over 35C
Shell Rotella 10W, 20(W) 20(W) 30, 40 50

Other brands are listed as well. Two of our three dive boats run Rotella in modern turbo diesels. These vessels run 60 miles RT offshore near Cape Hatteras maybe 200 days a year. One of them oftens run twice a day. Non-oil scientists might consider this a decent testimonial for Rotella, the good oil with the funny name.

[a64pilot]

Sulfur is absolutely one way acids get into oil, another very prevalent way is from moisture. If your engine run times are short, or not under a heavy load, then it's probable that your oil temp does not get to 180f, a temp that is pretty much recognized as being warm enough to cook off the moisture. Since moisture ends up as acids in your oil, I believe a high TBN is a good thing.
I believe a lot of us operate our engines for relatively short times and or under light loads, which is I don't believe the case for most Diesels, occasionally of course we get becalmed and run one for a day or two straight, but that's sort of the exception isn't it?

[Dockhead]

Originally Posted by a64pilot

Anyone gone over to bobistheoilguy.com and run this up over there?

I have a 27 yr old Yanmar 4JHE, I run the pure syn version of Rotella, Shell Rotella® Products - Shell Rotella I buy into it's a "better" oil, largely due to corrosion resistance as my engine isn't run as often as if it were a power boat. Viscosity with Syn oils is different, viscosity improvers that have to be put into regular oils may not have to be used in Syn oils.

I feel pretty strongly, especially for older engines that a straight weight, decent quality oil may be the best thing as one of the first of the additive packages that break down in oil is the viscosity improvers.

Vast majority of the time your changing Diesel oil not because it's broken down, but because it's laden with soot and this soot is abrasive, leads to maybe a by-pass flitration system? But heck I'm a sail boat, I'd rather spend that money somewhere else.

Personal opinion, oil wise best thing you can do is change it often and on a schedule, take calender time in account too, not just operating hours. Oil is at it's best just when it comes out of the can, from that point on it begins to degrade, you pick how far before it's changed.

Regular, frequent oil changes are far more important than oil type or brand for engine longevity.

If you are changing oil much sooner than it gets broken down, because it is full of soot -- and I heartily agree with this -- then why in the world would you use an oil designed to extend oil changes -- that is, to take the oil change interval in the opposite direction from what you're suggesting? It seems logically inconsistent. I'm not even mentioning the warnings discussed above about the ways in which synthetic oil can harm boat engines; that's a separate issue.

I agree with your logic about frequent oil changes. But I think that very logic implies that it is better to use cheap oil, to mfg specifications, with few additives, and change it faster than it can possibly break down. That way, we keep the soot down, and automatically the acid is kept down, and we don't need long-lasting anti-corrosion packages, much less synthetics.

[a64pilot]

Originally Posted by Dockhead

I agree with your logic about frequent oil changes. But I think that very logic implies that it is better to use cheap oil, to mfg specifications, with few additives, and change it faster than it can possibly break down. That way, we keep the soot down, and automatically the acid is kept down, and we don't need long-lasting anti-corrosion packages, much less synthetics.

What you say above is logical and hard to refute, especially on an engine that gets a significant amount of time put on it, but mine doesn't run much or very often

First I don't buy into all the nonsense about Syn oil being bad for anything, or for example that your rings won't seat if you break in an engine with Syn oil etc. It's been around for far too long for any of that to be true. One little exception is you'll may never see a pure Syn Aircraft oil, reason is the salts that form in the combustion chamber when a leaded fuel is used, now when and if lead in Avgas goes away, you'll see Syn oil there too. Has nothing to do with marine Diesels though.

Except, the long lasting anti - corrosion package part, any engine that spends a significant part of it's life sitting, especially in a humid environment, can benefit from a good anti-corrosion package, and there is truth to the most expensive oil get the best / most expensive additive packages. Back to the Airplane thing as my experience base is there, one of the two major engine manufacturers has had a premature cam wearing issue for almost forever. Now the highest loading in any piston engine is of course the cam / cam follower, high wear is often the result, many years ago an additive was formulated to help deal with this high pressure area in the Lycoming engine. Several years later and we are still having the camshaft failures.
A lot of us believe that the leading cause is the camshaft sits high in the engine case, the engine are infrequently flown and when they sit, a little bit of flash rust or corrosion may occur on the face of the cam and of course when you get through that face hardening, wear is fast. People that use an oil specially formulated with an exceptional anti-corrosive package, have fewer cam failures

What this has to do with Marine Diesels is that a lot of sailboat engine sit more than they used to, and they sit for longer periods and are used infrequently and for short periods at low loads, all of these operating conditions lead to having a very good anti-corrosion package, something that is usually in the more expensive oils.

My engine for example is 27 yrs old, based on a very extensive inspection, I believe the factory hour meter was correct, that it had accumulated 500 hours of run time in 27 yrs, that is an exception of course, but illustrates the point that some at least sailboat engines aren't used very much.

Now on Blue Crabs dive boat for example that is run almost every day, and done so I'm sure for a decent long time, at 75% power or so, I agree with your statement completely.

I may be wasting a little money, not much as we are talking an oil change every 6 months, but I sleep better. I may have wasted money on the oversize Rocna, I mean my old Danforth held fine as long as I set it, but I sleep better with the oversize Rocna, I feel better about using the best oil that is available.
I use either K&N or Mobil One oil filters as well, based on a report I read years ago that showed they filtered to the smallest particles of all widely available filters. They both cost considerable more than most filters too.

[Dockhead]

Originally Posted by a64pilot

What you say above is logical and hard to refute, especially on an engine that gets a significant amount of time put on it, but mine doesn't run much or very often

First I don't buy into all the nonsense about Syn oil being bad for anything, or for example that your rings won't seat if you break in an engine with Syn oil etc. It's been around for far too long for any of that to be true. One little exception is you'll may never see a pure Syn Aircraft oil, reason is the salts that form in the combustion chamber when a leaded fuel is used, now when and if lead in Avgas goes away, you'll see Syn oil there too. Has nothing to do with marine Diesels though.

Except, the long lasting anti - corrosion package part, any engine that spends a significant part of it's life sitting, especially in a humid environment, can benefit from a good anti-corrosion package, and there is truth to the most expensive oil get the best / most expensive additive packages. Back to the Airplane thing as my experience base is there, one of the two major engine manufacturers has had a premature cam wearing issue for almost forever. Now the highest loading in any piston engine is of course the cam / cam follower, high wear is often the result, many years ago an additive was formulated to help deal with this high pressure area in the Lycoming engine. Several years later and we are still having the camshaft failures.
A lot of us believe that the leading cause is the camshaft sits high in the engine case, the engine are infrequently flown and when they sit, a little bit of flash rust or corrosion may occur on the face of the cam and of course when you get through that face hardening, wear is fast. People that use an oil specially formulated with an exceptional anti-corrosive package, have fewer cam failures

What this has to do with Marine Diesels is that a lot of sailboat engine sit more than they used to, and they sit for longer periods and are used infrequently and for short periods at low loads, all of these operating conditions lead to having a very good anti-corrosion package, something that is usually in the more expensive oils.

My engine for example is 27 yrs old, based on a very extensive inspection, I believe the factory hour meter was correct, that it had accumulated 500 hours of run time in 27 yrs, that is an exception of course, but illustrates the point that some at least sailboat engines aren't used very much.

Now on Blue Crabs dive boat for example that is run almost every day, and done so I'm sure for a decent long time, at 75% power or so, I agree with your statement completely.

I may be wasting a little money, not much as we are talking an oil change every 6 months, but I sleep better. I may have wasted money on the oversize Rocna, I mean my old Danforth held fine as long as I set it, but I sleep better with the oversize Rocna, I feel better about using the best oil that is available.
I use either K&N or Mobil One oil filters as well, based on a report I read years ago that showed they filtered to the smallest particles of all widely available filters. They both cost considerable more than most filters too.

Well, it's your own choice whether or not to believe that synthetics are harmful to marine diesels -- there is a lot of different evidence that it is, but you are free, of course, to ignore it.

But even if we put the question of harmfulness aside, what possible usefulness do synthetics have for marine diesel engines? We don't have high bearing loads, we don't have high combustion temps, and for goodness' sake, we don't want to extend oil change intervals. Those are the raisons d' etre of synthetic oil, so why would you use them in marine engines which don't need any of that? Synthetic oil -- which I use in every non-marine engine I own, including a high performance snowmobile, cars, etc. -- is designed to solve several problems which marine engines simply don't have. Even if you assume that they are not harmful (which I don't), there is simply no value in their use in marine engines.


To some extent, the same arguments apply to high TBN oils. As Snowy Petrel above showed, they are needed for high sulfur fuel. Or for cases when you want to extend the oil change interval -- so that the oil can keep absorbing acid while you get a few more hundred hours out of the oil. But if you actually shorten the oil change interval, rather than extending it, and if on top of that you are using low sulfur fuel, then why in the world would you need it, even if it's not harmful? Additives which are designed for some other purpose, like keeping acid down, are not going to be doing any lubricating, so surely you don't want any more additives in your oil than what you actually need, EVEN if they are not harmful, which is doubtful (see article posted by Snowy Petrel for just one more example). The fundamental fallacy many people suffer from is to think that because some additives are useful, then more additives -- i.e., a "higher" grade of oil -- must be better. It's simply not true. The best oil for your engine is the one which has just the right amount of the right kinds of additives, and no more than that. The manufacturer's recommendations (as has been stated so many times in this thread) is absolutely the right place to go to find this out.


Talking about moisture forming acid in motor oil (by mixing with sulfur combustion products) -- Why would moisture form inside an engine which is not running? You might conceivably get a very small amount of condensation in a crankcase which is undergoing a temperature cycle -- that is, and engine which is being run and shut down, but the amount of condensation you can get in an engine which is not being run must be measured in the micrograms or be completely unmeasurable. This is similar to the fuel tank condensation issue we discussed recently, except even much more trivial since (a) unlike fuel tank breathers, crankcase breathers do not vent to the outside; and (b) air volume in crankcases is very tiny.

And in any case, moisture in the oil is extremely harmful without consideration of the the question of acid, so high TBN oil is hardly a solution to that problem. Frequent oil changes, on the other hand, are a solution. As well as fixing the leaking heat exchangers or whatever are the much more likely source of any water in the oil.

As to using expensive filters -- here I agree with you completely. I wish I could get those kind of filters for my Yanmar.


One thing really missing from this discussion is any mention of oil analysis. Serious professional users of diesel engines almost all do this. A laboratory analysis of your oil is the only way to know whether or not the oil is becoming acid, whether it is breaking down, whether there is too much soot in it, etc., etc.

If you are pushing the envelope with change intervals, which is the correct thing to do if you're running a fleet of trucks or fishing boats, then this helps you make sure your oil is performing well as the hours rack up, and you will see if need a higher TBN oil, for example.

Sticking strictly to the manufacturer's change intervals is a decent way to avoid having to analyze your oil, because these intervals are designed, in conjunction with the recommended grade of oil, to cover just about any eventuality with the right amount of the various additives.

And if you shorten change intervals, as many of us do, then this works even better -- the risk of running out of alkalinity or accumulating water in the oil or something like that goes down rapidly as you shorten the change interval. You are wasting oil which is not being fully used up, but that is a pretty cheap price to pay for this insurance, and the money you save on analysis might pay for it with the small oil capacities our boats generally have. It simplifies the whole process and lets you think less about oil.

But why would you increase the additive packages, without even checking by analysis whether you have a problem? It makes no sense.

[sailorboy1]

I just use oil that says it is for "diesel" engines. While I'm sure there are differences in oils for the most part I think it is just on paper.

When I was in the Navy there was time when every different piece of equipment had its' own oil/grease spec and it got to the point that we had some many different ones it was crazy. Finally someone high decided that we would go to 1 oil and 2 greases and just switched over to those, and we didn't even flush out the old ones just started using the new ones. No equipment damage occurred.