Fully synthetic lube oil in Yanmar 3YM30

[vyv_cox]

If you really want to use the best oil for the engine I think it would be difficult to beat API CI-4. With the general reduction in fuel sulphur content it has been possible to reduce TBN in lub oils, especially for engines not using EGR. I have seen API CI-4 oils with a TBN as low as 8, which is similar to API CF-4 but with an excellent additive package. Some commercial oils cover a wide range of specifications including CI-4 and may well have higher TBNs, so some care is needed when selecting.

 

[RichardS]

Thanks for more helpful replies. Even with the very low hours it'd be daft not to ask.

From Vyv Cox's post it seems synthetic in a 3YM30 is more overkill than destroyer of the engine. Please correct me if I got this wrong.

The advantage of a synthetic oil in a car engine (and I've used synthetic only since the mid-70s) is that the synthetic oil chains do not breakdown into black carbon as quickly as mineral oils. This has two advantages, the psychological one is that the engine internals will stay shiny metal rather than going brown, and the technical one is that the engine can go longer between oil changes.

If you change the oil every year the latter advantage is no advantage.

Richard

 

[sailorman]

The advantage of a synthetic oil in a car engine (and I've used synthetic only since the mid-70s) is that the synthetic oil chains do not breakdown into black carbon as quickly as mineral oils. This has two advantages, the psychological one is that the engine internals will stay shiny metal rather than going brown, and the technical one is that the engine can go longer between oil changes.

If you change the oil every year the latter advantage is no advantage.

Richard

The service manage in my local Ford garage said he would use synthetic oil in all engines

 

[Tranona]

The service manage in my local Ford garage said he would use synthetic oil in all engines

so, is he an expert on low specific output diesels then?

Simply no comparison between the engines he deals with and the ones in our boats so a useless piece of information.

BTW my garage also uses synthetic oils because the manufacturer recommends it, but my diesel car produces 70 BHP per litre, revs to 4500 rpm compared with 35 BHP per litre at maximum 3200.

 

[sailorman]

so, is he an expert on low specific output diesels then?

Simply no comparison between the engines he deals with and the ones in our boats so a useless piece of information.

BTW my garage also uses synthetic oils because the manufacturer recommends it, but my diesel car produces 70 BHP per litre, revs to 4500 rpm compared with 35 BHP per litre at maximum 3200.

Note "all"

 

[Tranona]

Note "all"

I have noted - and i assume you posted to illustrate that your service manager has not got a clue what he is talking about when it comes to small boat and industrial diesels.

 

[CAPTAIN FANTASTIC]

My Volvo MD11C is over 40 years old and it has been running on synthetic oil for over 10 years. Synthetic oils are superior lubricants in every way.

 

[PaulRainbow]

Sounds like an oil change could be first on my list of jobs.

Be careful of swapping types of oil, generally best to keep it on what it's used to.

 

[RichardS]

Be careful of swapping types of oil, generally best to keep it on what it's used to.

I can't really work out why that would make engineering sense Paul. Do you have a theory?

Obviously it's best not to move to a poorer quality of oil but I guess you're not referring to that.

It used to be the case that I used to run-in my cars and bikes for the first 500 miles or so on mineral oil before swapping to synthetic although that's a specialised case of oil swapping.

Richard

 

[Hadenough]

I thought the issue with older engines was that synthetic oils attacked the older generation seals. Whatever, for the sake of £30 or less I change the oil in my 40yr old Ford every 100hrs using mineral, makes me feel better :encouragement:

 

[tgpt21]

If you check the Yanmar operator manual it lists the types of oils to avoid only very basic oils are recomended because higher specs can cause wear.

 

[RichardS]

If you check the Yanmar operator manual it lists the types of oils to avoid only very basic oils are recomended because higher specs can cause wear.

Are you sure that Yanmar don't recommend a synthetic oil of the same viscosity rating as the recommended mineral oil simply because they have not longevity-tested the engine with the synthetic version?

Richard

 

[lw395]

The manual says;
DO NOT use The following engine
oils.
API : CG-4, CH-4
ACEA : E-1, E-2, B grade
JASO : DH-2, DL-1
Reason
• API CG-4, CH-4
In case CG-4, CH-4 is to be used for
YANMAR YM diesel engine series,
there is a possibility that excessive
wears occur on the valve train system
due to the content of oil.
• ACEA E-1,E-2, B
These fuels are developed for the different type of diesel engines.
• JASO DH-2, DL-1
These fuels are developed for the different type of diesel engines.


I think the issue is likely the sulphur content of marine fuels in some parts of the world. Cg and Ch are for low sulphur fuel only?

 

[B58]

Are you sure that Yanmar don't recommend a synthetic oil of the same viscosity rating as the recommended mineral oil simply because they have not longevity-tested the engine with the synthetic version?

Richard

I f you use synthetic oil in your YM or any other yacht auxiliary, you will glaze your bores and start burning it! Your engine is a lightly used product in relation to powerboat engines that are close to full load during use, from experience the yacht auxiliary rarely reaches operating temperature before the sails go up...15w40 mineral is the correct product make sure you buy oil that is FCW rated.
I remember years ago Pat Manley embarrassingly suffered the same problem with his twin 3GM30 installation.

 

[RichardS]

I f you use synthetic oil in your YM or any other yacht auxiliary, you will glaze your bores and start burning it! Your engine is a lightly used product in relation to powerboat engines that are close to full load during use, from experience the yacht auxiliary rarely reaches operating temperature before the sails go up...15w40 mineral is the correct product make sure you buy oil that is FCW rated.
I remember years ago Pat Manley embarrassingly suffered the same problem with his twin 3GM30 installation.

My auxiliary engines have each done 4000 hours in 9 years .... which corresponds to a car doing something like 15,000 miles a year, with most of those revs being at a higher percentage of maximum revs than my car engine so hardly "lightly used" is it?

Either way, it's not going to cause a problem provided you can meet the viscosity requirements.

Richard

 

[awol]

My auxiliary engines have each done 4000 hours in 9 years .... which corresponds to a car doing something like 15,000 miles a year, with most of those revs being at a higher percentage of maximum revs than my car engine so hardly "lightly used" is it?

Aye, but some folk have proper boats that are fun to sail and don't motor everywhere.

 

[RichardS]

Aye, but some folk have proper boats that are fun to sail and don't motor everywhere.

It doesn't sound like you've ever tried to "sail" in the Med. :ambivalence:

Richard