Shoutout to Daddyo on oil

Awhile back you commented that you put regular weight Rotella in one engine and a Walmart synthetic in the other,

The synthetic you said ran much quieter...

Anything longer term now you want to relate?

I'm pretty sure you didn't blow anything otherwise we may have heard about it...but anything cool worth relating?

We get so much intergalactic noise on here about oil...some more real world experience with something other than "what HE said" should be used would be refreshing.

Howdy!
I prefer the synthetic multi-weight with one consideration worth noting. The muti-weight I run is 10W-40. The oil has less the viscosity when cold then a 40SAE oil. That said the start up has in my estimation better lubrication as the oil is thinner and better able to slosh around everywhere before the oil heats up and thins. The only issue is if your engine has external gasket and seal leaks then the leaks will be worse when the engine is cool vs the single weight.

Daddyo said:

Howdy!
I prefer the synthetic multi-weight with one consideration worth noting. The muti-weight I run is 10W-40. The oil has less the viscosity when cold then a 40SAE oil. That said the start up has in my estimation better lubrication as the oil is thinner and better able to slosh around everywhere before the oil heats up and thins. The only issue is if your engine has external gasket and seal leaks then the leaks will be worse when the engine is cool vs the single weight.

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How many hrs since switching to synthetic (if you don't mind and the straight wt guys don't form a lynch mob )?????

About 700 hours I think.

I run Mobile 15-40 synthetic in the tractors & trucks. Works great. 5000 miles with the truck. Since the boat is fairly new to me, I'll use the Mobile 15-40 synthetic on the boat. The PO used it prior to me. 500-700 hrs on the boat engines? I would think it would be well limits of the oil?

Daddyo said:

About 700 hours I think.

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Thanks!!!

Correction. I run 15w40.

Interesting as I normally run Rotella 15W40 dino oil but in my truck for the winter I switch to the synthetic Rotella which I'm pretty sure is 5W40.

I'm surprised that the synthetic doesn't have a lower number than 15 as many do.

Mark,
You wrote;
"That said the start up has in my estimation better lubrication as the oil is thinner and better able to slosh around everywhere before the oil heats up and thins."

I think the ability of oil to keep engine bearings ect apart thus eliminating metal to metal contact is much more important than it's ability to "slosh around everywhere". Thick oil is better equipped to keep parts apart. And unless an engine has been sitting for a very long time there will be plenty of oil for that #1 job. And good thick oil if the skipper is using a quality 30wt oil like Chevron Delo straight 30.

manyboats said:

Mark,
You wrote;
"That said the start up has in my estimation better lubrication as the oil is thinner and better able to slosh around everywhere before the oil heats up and thins."

I think the ability of oil to keep engine bearings ect apart thus eliminating metal to metal contact is much more important than it's ability to "slosh around everywhere". Thick oil is better equipped to keep parts apart. And unless an engine has been sitting for a very long time there will be plenty of oil for that #1 job. And good thick oil if the skipper is using a quality 30wt oil like Chevron Delo straight 30.

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The above has been proven wrong, which for the last 20 years every major automaker has switched to multi weight oils.

Mark is correct. Most engine wear occurs at startup, thus a lighter oil becomes more important for the long run.

Mark's advice about putting synthetic in a used engine is also what my experience has been.

If I was starting out with a new engine, I would use synthetic, but with a used engine like I have, I would expect my oil consumption to double, with little benefit in the long run.

Wxx3 said:

The above has been proven wrong, which for the last 20 years every major automaker has switched to multi weight oils.

Mark is correct. Most engine wear occurs at startup, thus a lighter oil becomes more important for the long run.

Mark's advice about putting synthetic in a used engine is also what my experience has been.

If I was starting out with a new engine, I would use synthetic, but with a used engine like I have, I would expect my oil consumption to double, with little benefit in the long run.

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...one of the reasons I started this thread....

Well I guess that's why there is many different products ... lots of different opinions. The main reason there are different products is that there are different uses and applications. 15W40 is excellent for trucks but there is no standards for marine engines. The specs for marine engines may just be passed on from what the oil manufacturers spec for road vehicles and the legal climate of late will probably incline them to cover their tails in this way.

At any rate no one is going to suffer from using or not using syn or MV oils but there is no need for either. I'm guessing in industry most Diesel engines that normally have 10 minutes to warm up and are not subject to cold temps will be using straight weight oil.

Wxx3 said:

If I was starting out with a new engine, I would use synthetic

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I follow the builders warranty guidelines on new engines. There are many where synthetics are carefully spelled out if not verboten as not all are created equally. On big fleets where the engines are guaranteed for X hours between rebuilds, synthetics are cost prohibitive as the rebuild guarantee hours are the same.

But as Eric says, lots of choices and we little hour use people will not suffer unduly no matter what decent branded oil we use.

It is all about marketing an expensive product we don't really need. Heck I'm as guilty as the next guy as I buy Tommy Bahama clothing.

On dark, moonless nights, I rub coconut oil all over my Bruce.

(oops...this is about engine oil, not anchors, isn't it? Sorry, never mind...)

psneeld said:

Interesting as I normally run Rotella 15W40 dino oil but in my truck for the winter I switch to the synthetic Rotella which I'm pretty sure is 5W40.

I'm surprised that the synthetic doesn't have a lower number than 15 as many do.

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The Shell 5w40 oil I used to use was a semi synthetic oil but it looks like it is now a full synthetic which does not matter to me. For a few years I was able to get JD 0W40 oil cheaper than the Shell 5W40 oil. The last time I priced the JD oil it was more expensive than Shell, so when my five gallon bucket of JD is emptied, if the Shell oil is still cheaper, I will be back to Shell 5W40 oil.

Later,
Dan