SAE 15w-40 instead of SAE10-30?

[AJ-SSCS]

Hy! My phasor k4 21kw runs with SAE 10w-30 (diesel engine) wich is not so easy to get everywhere, the other generator and the mainengine are using SAE15-w40, would it be a problem to use this type of oil in the phasor as well? I am never located in areas under 0 degree celsius.... Thanks in advance 😊


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[Wotname]

I can't see any problem with using the 15W-40 in lieu of 10W-30 given your statement of no cold temperatures.

However, do all your engines call up the spec of CF or CH or whatever. There can be some differences here that may or not be important?

[AJ-SSCS]

Hm as i am not so familiar with engines i dont know what ch or cf is, the phasor for example hust tells me in the manual : Engine oil should be MIL-L-2104C or have API classification of CD grade or higher. Does the 15 stand for the viscosity?


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[Wotname]

Originally Posted by AJ-SSCS

Hm as i am not so familiar with engines i dont know what ch or cf is, the phasor for example hust tells me in the manual : Engine oil should be MIL-L-2104C or have API classification of CD grade or higher. Does the 15 stand for the viscosity?


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Yes, I should have said "what API classification".

You probably won't easily find a CD oil these days but CF in generally accepted as being suitable (and perhaps better). There reasons not to use the latest (highest) API classification but I dont know all the detail. There are some threads of CF and I or others can point you to them.

The viscosity range over varying engine temperatures is given by the 15W-40 etc. The lower the number, the thinner the oil. The first number is how "thin" the oil is at low temperatures and the higher number is how "thin" the oil is at the normal engine operating temperature.

So you see with a multigrade oil, it starts of thin when colder and gets "thicker" as the engine warms up. A single grade oil say SAE30, starts of thick and gets a little thinner when hot.

Please note this is a very very very simple explanation and hopefully more knowledgeable posters will show up to help you and perhaps correct me .

[mrm]

Originally Posted by AJ-SSCS

[...] Does the 15 stand for the viscosity?

Not directly. It is more related to temperature ranges where viscosity will stay within 'reasonable' range (i.e not as thick to make engine turning over difficult on one end, and not too runny, to keep lubricating properties on the other). In the end it amounts to the same, though. If you never experience cold temperatures, 15W40 will be just fine.

However, keep to oils formulated for diesel engines. They have different additions package formulations to better disperse soot and neutralize acidic blow-by products.

[Wotname]

Originally Posted by mrm

....
However, keep to oils formulated for diesel engines. They have different additions package formulations to better disperse soot and neutralize acidic blow-by products.

And stick as close as you can to the API classification but if you have to vary, go to the next highest classification.

FWIW, the first letter in the API classification tells you if it is suitable for diesel or petrol (gasoline).
C = diesel (compression ignition technique)
S = gasoline (spark igition systems technique)

[DeepFrz]

You really don't need a multi viscosity oil in a marine diesel engine unless you are expecting to operate in a cold environment.
Motor Oil Viscosity Grades Explained in Layman's Terms

[Dulcesuenos]

Originally Posted by DeepFrz

You really don't need a multi viscosity oil in a marine diesel engine unless you are expecting to operate in a cold environment.
Motor Oil Viscosity Grades Explained in Layman's Terms

The issue weve seen with this is the straight weights i.e. sae 30 or sae 40. Tend to shear more under severe use then a multi viscosity oil that has viscosity improvers etc etc, I could bore you with details but I wont.

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[Wotname]

Originally Posted by Dulcesuenos

The issue weve seen with this is the straight weights i.e. sae 30 or sae 40. Tend to shear more under severe use then a multi viscosity oil that has viscosity improvers etc etc, I could bore you with details but I wont.

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Perhaps you could bore me with the details then. At least some of them.

And is there any time a multigrade is worse than a single grade (in general recreational boat use)?

[DeepFrz]

I really don't think many sailboat engines operate, at least for any length of time, under severe conditions. I think that big rigs rolling through mountain ranges at 100+ f or - 40 f are operating in severe conditions not sailboat engines.

[Dulcesuenos]

Originally Posted by Wotname

Perhaps you could bore me with the details then. At least some of them.

And is there any time a multigrade is worse than a single grade (in general recreational boat use)?

Multigrade technology far surpasses older straight weights. I know people say well sailboat diesels are "old tech " and dont need better oils, but fuels are not what they used to be, now its ultra low sulfur etc, which does impact engines in many ways. Diesels of the 70's, and 80s also were lower rpm, newer diesels are 3100 plus w many being 3600 rpm. So if you think a boat running 3000 rpm for 20 hours is not severe duty or at the very least a bit more severe than hwy driving at 2000 rpm. Straight weights start out thick then break down as they heat up. They "shear " and lose viscocity to a certain degree. A slightly clogged oil cooler etc and you loose a lot of protection. Multigrades use much better technology , better additives, especially a good oil like Shell Rotella 😉
I know some mercruiser gas inboards require a straight vis, some people cant get with the times. Lol

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[Catalysis]

You shouldn't have any problems substituting with 15w-40.
You are essentially getting the same protection over a wider operating temperature window.
You are likely buying more performance than you need but keeping your lube inventory simple has merit.
Go with a well known marine lube brand like Chevron's Delo or Shell's Rotella and you'll be fine.
Paul




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[AJ-SSCS]

Wow so much help, i appreciate it 😊 thanks u re awesome!! AJ


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[Hard Rock Candy]

Here's a strange story. I bought my sailboat in Florida. I soon started supplying it with stuff like Oil, Shell Rotella, Oil filters and so on. So I left Florida for the Bahamas. I had to motor almost all the way to Nasua. During that trip I used 2 and 1/2 gallons of oil. I went to a motor supply shop and they told me to burn Dello. The reason the Shell went away so fast was because I had an old slow Yanmar made in 76. that was salt water cooled and it barely warmed up when running. The Shell Rotella was for a high-speed engine that had a thermostat that got up to operating temperature. Never had another problem with that motor. Mac

[jpstevens]

As we are discussing engine lubrication, what are the opinions regarding alternate filters to the Yanmar for the newer high RPM engines?