Sae 40

[Bluestream]

Re: Sae 40

Some of you guys crack me up. Reminds me of of when my grandpa ran the family small town gas station decades ago and people would demand straight 30w oil for their lawn mowers. They wouldn't believe a 10-30 would be just fine, so he happily brought in 30w to sell to them at a 100% markup.

Actually 30 weight is much better for air cooled lawn mowers than 10W30. Same reason as for marine, air cooled engines run hot and need an oil that won't shear down. Most owners manual recommend the 30W for air cooled. Grandpa did the right thing!

I would be very careful if you're running a straight 30w oil. Much of the straight 30w oil out there is non-detergent oil.

The opposite is actually true. Almost all off the shelf 30W oils will be detergent oils. Anything at Walmart, or an auto parts place will be detergent. Castrol Shell whatever.

As for dino oil vs synthetic. Synthetic is a bit better on an engine where you have lots of cold starts and many short trips where the engine doesn't get a chance to fully warm up. On a boat, I don't think it's necessary. At 19 years old, I wouldn't even consider it. The "damage" has already been done.

Again no damage has been done. You can switch to synthetic at any time and get the advantages that synthetic may offer.

Educate yourself about motor oils here: http://www.bobistheoilguy.com/forums...s.php?ubb=cfrm

Basics can be found here: http://www.bobistheoilguy.com/cms/index.php?option=com_content&view=article&id=83&Itemid=92

Explains what happens to VII in a hot oil environment.

 

[45Auto]

Re: Sae 40

Good point. Taking the advice on engine oil for a small block Chevy from Yamaha is like taking outdrive oil advice from GM.

You really don't think Yamaha did any research before publishing their oil recommendations? I'd take Yamaha's 15 year old advice LONG before I'd believe anything posted on an internet forum.

If you don't like that, it's not real difficult to find the latest recomendations from Volvo and Merc.

engine failures from using the "wrong" oil are virtually unheard of.

Sounds impressive. Any data to back that up? How many destroyed marine engines have you performed a failure analysis on? Do you offer a warranty on engines you sell, regardless of the type of oil used?

 

[Bluestream]

Re: Sae 40

If you would like to know why conventional multi-grade oils are not well suited to an engine that runs high oil temperatures have a look at this page.

http://www.calsci.com/motorcycleinfo/Oils1.html

You can skip down to the "Making Multi-grade oil" section mid way down.

 

[Alpheus]

Re: Sae 40

I think people start oil threads so some of the new people can get their post count higher.

There, I just added one to mine. I'm a little smarter now...

 

[StorminNormin]

Re: Sae 40

I don't get it why would anyone care how many posts they have? Do we get money for more posts???

 

[HT32BSX115]

Re: Sae 40

I don't get it why would anyone care how many posts they have? Do we get money for more posts???

A high "Post Count" and about $3.50 gets a mean cuppa coffee at Starbucks!!

If you would like to know why conventional multi-grade oils are not well suited to an engine that runs high oil temperatures have a look at this page.

http://www.calsci.com/motorcycleinfo/Oils1.html

You can skip down to the "Making Multi-grade oil" section mid way down.

The above article by the Electrical Engineer is actually a pretty good one. He's pretty much done his homework.

You don't have to be a mechanical/chemical/petro engr to read his references.

Marine engine "manufacturers " like Mercruiser, Volvo, OMC, and others probably make their recommendations on the grade and type of oils to use based on the conditions most recreational boaters would experience.


Think about it. You don't generally operate your boat in sub-freezing weather. The engine never operates above about 150-170 degreesF.


With such a narrow operating temp range for 99% of marine engines, using a straight SAE 30 or 40 begins to make sense.

Multigrades are simply not necessary. Ask the people here that work on these engines for a living and they'll tell you that they haven't seen many engines that "failed" due to oil type. (or even frequency of changes)

It probably happens, it's just that they don't see a lot of that. These are engines that for most people, get operated for a few short months out of the year, and get parked for the rest of the year.

A lot of them run trouble free for 20, 30 or 40 years, get sold, then get block-cracked because the "new" owner doesn't drain the block!

This "oil" thread (like ALL the others) simply turns into a "I use XXX oil and have had good service" or "Have never had a problem with YYY oil"


The fact of the matter is......we all just like to talk about "what we do"


(and it drives up the post-count!!)

 

[veritas honus]

Re: Sae 40

A high "Post Count" and about $3.50 gets a mean cuppa coffee at Starbucks!!

The above article by the Electrical Engineer is actually a pretty good one. He's pretty much done his homework.

You don't have to be a mechanical/chemical/petro engr to read his references.

Marine engine "manufacturers " like Mercruiser, Volvo, OMC, and others probably make their recommendations on the grade and type of oils to use based on the conditions most recreational boaters would experience.


Think about it. You don't generally operate your boat in sub-freezing weather. The engine never operates above about 150-170 degreesF.


With such a narrow operating temp range for 99% of marine engines, using a straight SAE 30 or 40 begins to make sense.

Multigrades are simply not necessary. Ask the people here that work on these engines for a living and they'll tell you that they haven't seen many engines that "failed" due to oil type. (or even frequency of changes)

It probably happens, it's just that they don't see a lot of that. These are engines that for most people, get operated for a few short months out of the year, and get parked for the rest of the year.

A lot of them run trouble free for 20, 30 or 40 years, get sold, then get block-cracked because the "new" owner doesn't drain the block!

This "oil" thread (like ALL the others) simply turns into a "I use XXX oil and have had good service" or "Have never had a problem with YYY oil"


The fact of the matter is......we all just like to talk about "what we do"


(and it drives up the post-count!!)

The fact of the matter is......we all just like to talk about "what we do"
Very well spoken. Thank you... Isn't that the whole point of any forum?... To talk about what we do... This is how we help each other. It's great to find humor in the things we talk about. If we talk about some of the same things over and over again, maybe it just helps to be reminded or have our thoughts reenforced. All this info has been great. Any more is certainly welcome.

Safe and happy boating always!!!

 

[Lou C]

Re: Sae 40

After all is said and done, the viscosity of the oil, and its ability to stay in grade, is more important than whether it's synthetic or not. That's why I used both straight 30 or 40 depending on the outside temps. Tests of multi weight oils (esp dino oils) show that they shear down in grade when in use. So a 10w-30 might wind up as a 10w-20 after hours of running at a steady 3500 rpm which is typical boat use. You do not NEED the 10w aspect because you are not doing cold starts (below 40 degrees). So why use an oil with VI improvers, which are known to cause trouble in certain applications? I'd use either one of the straight weights in heavy duty oil formulations or the Merc 25/40 before I searched high and low just to find a syn 30 or 40......

and that's all I got to say about that.........

 

[LAC_STS]

Re: Sae 40

+1


Thats what I do.

SAE 40 in the summer when its 90+ down here, and SAE 30 as soon as it starts cooling down a little.

 

[veritas honus]

Re: Sae 40

+1


Thats what I do.

SAE 40 in the summer when its 90+ down here, and SAE 30 as soon as it starts cooling down a little.

It cools down in South Florida?

 

[Bluestream]

Re: Sae 40

Oil applications are always a topic that brings up a lot of controversial opinions. Fact is my people don't know much about oil or the ratings and where to use what product and when. I have not been a huge fan of synthetic oils until recently. I do like synthetic Lubricants for transmissions, differentials, because these lubricants stay in for long periods of time and repairs can be expensive and time consuming. Cold flow properties of synthiscs can be helpfull in cold winter areas such as where I live.

For marine use, I think it depends on the application. I sure won't be buying any for my 1988 Cobra, but then I don't intend to keep this boat for long anyway

 

[LAC_STS]

Re: Sae 40

Yea. Thursday when I went out fishing it was 80 out until about 5 PM then it started dropping. It was 60 by the time I got back at midnight.


Was just saying. In the dead of summer it's close to 100. In the fall and spring it's around 70 usually.