Synthetic for 3208

smitty477 said:

Oil for yacht engines...

Oil for yacht engines – Cox Engineering

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Well that’s the first time I have seen a claim that full synthetic is bad for an engine.

I read the article wherein the author keeps referring to yacht “ auxiliary” motors. My sense was that he was perhaps discussing smaller sailboat motors that may not be germane to this discussion? See what you think.

smitty477 said:

Oil for yacht engines...

Oil for yacht engines – Cox Engineering

Click to expand...

I don't know when this was written but the performance claims referenced in the text are out of date, by decades. Also the description of base oil being distilled from crude oil is also no longer applicable. No modern base oil is made this way, hydrocracking and isomerization is nearly universal, i.e. the base oil is synthesized by breaking apart the molecules and reassembling them in a configuration suitable for lubricating oil.

While there are API CD oils SAE 30/40 still marketed, mainly in the less developed world, these are lower performance engine oils with no actual testing supporting their claims (tests are long obsolete and not available). Oh, and the recommendation against synthetic may be a hang over from early seal problems as well as the typical wide viscosity cross grade of synthetics which may not be ideal in older diesels.

Bonedoc said:

I read the article wherein the author keeps referring to yacht “ auxiliary” motors. My sense was that he was perhaps discussing smaller sailboat motors that may not be germane to this discussion? See what you think.

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In the UK, and Australia, yacht = sailboat, as it is used in USA. So yes.

ksanders said:

Well, I use Royal Purple duralec 15w-40 in my Cummins 6BTa engines, and my generator.

Will it help anything??? I have no clue but I feel better about it.

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The Royal Purple product should be equivalent to the main line oils like Delo 400 or Rotella T. Royal Purple is a smaller marketer so I don't know exactly who is providing their technology, most likely Lubrizol or maybe Infineum. The lubricant additive suppliers develop and qualify almost all the oils. The companies who actually develop and qualify the additive technology are Lubrizol, Chevron-Oronite, Infineum, and Afton. But in any case it is certain Royal Purple purchases an additive package qualified for use in the base oil(s) that they purchase. In other words I wouldn't worry about using it.

tiltrider1 said:

You can use synthetic but it’s a waste of money. Synthetic is just standard oil that as been further refined. It’s purpose is to not break down when used in tight clearance applications like modern high performance engines. 3208’s like heavy duty motor oil. Shell T4 or Delco 400. You can use T5 or T6 but you won’t gain anything.

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Synthetic oil is not further refined standard oil. Feedstock oil is distilled into all its component parts and then recombined in the exact ratios required for best performance and longevity. The impurities in standard oil aren’t present in synthetic because it’s not there to begin with. And the component parts are in the exact proportions needed. Standard oil is feedstock oil refined to the desired viscosity, as many impurities as possible are filtered out, and each brand adds their own proprietary additives. There’s really no comparison when it comes to an engineered oil solution.

I recently converted my twin 454 gassers to full synthetic with no seal leakage at all and my expectation is that the oil will be viable for much longer with less impurity driven degradation.

Tak

Takoradi said:

Synthetic oil is not further refined standard oil. Feedstock oil is distilled into all its component parts and then recombined in the exact ratios required for best performance and longevity. The impurities in standard oil aren’t present in synthetic because it’s not there to begin with. And the component parts are in the exact proportions needed. Standard oil is feedstock oil refined to the desired viscosity, as many impurities as possible are filtered out, and each brand adds their own proprietary additives. There’s really no comparison when it comes to an engineered oil solution.

I recently converted my twin 454 gassers to full synthetic with no seal leakage at all and my expectation is that the oil will be viable for much longer with less impurity driven degradation.

Tak

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Your 454’s will last just as long on standard oil as they will with synthetic oil. While I might not be technically correct in my statement neither is the name synthetic.

Is anyone aware of any marine engine failures due to lube oil that was changed on schedule?

So besides anecdotal feel good stories and perhaps a few special situations my older mechanical Yanmar 6-LPA (400 hr) will do fine with Shell Rotella T1 dino with annual changes including filter… and I’ll concern myself with other issues.