2300 Hours, Should I go thicker?

[Tom.B]

Getting ready to do annual engine work on my Perkins 135hp. For the past three years I have used Rotella T 15W40 because that's what the previous owner used. Come to find out, for above 80-degrees the manual calls for SAE30. With 2300 hours, the engine has a few little leaks (hey... it's a Perkins) but I still haven't needed to add oil throughout the past year.

Should I stay with 15W40 or go to 30?

 

[psneeld]

Getting ready to do annual engine work on my Perkins 135hp. For the past three years I have used Rotella T 15W40 because that's what the previous owner used. Come to find out, for above 80-degrees the manual calls for SAE30. With 2300 hours, the engine has a few little leaks (hey... it's a Perkins) but I still haven't needed to add oil throughout the past year.

Should I stay with 15W40 or go to 30?

For the summer I would go with Rotella 40. The 15W40 would be OK too as you will still have cool mornings for a month or two. I've run 15W40 for lots of miles/hr in diesels and so have all the maritime companies I have worked for. Only a few diehards still go with a straight weight.

That said I went with Rotella 30 but I'm up in Jersey parked for the summer and I'll switch back to 15W40 when I leave to headsouth next December. After switcing to Rotella 30 a couple weeks back in Beaufort, SC...the cooler mornings and my Lehman starts a little slower than before I switched from 15W40.

But all in all..if you don't push your engine hard and only are gonna put 200 or less hrs on her/him...you could go 30, 40 or 15W40 and I doubt other than faster starts with the 15W40 on 40 degree or less mornings...you would probably never know or care.

 

[Pau Hana]

I think the multi-vis will be fine. While you're at it, get a sample from each engine analyed.

 

[Nomad Willy]

I use Delo 30 all the time except for mid summer. Then I mix 30 and 40W together. My engine is small and would probably crank smartly w 60W oil. But for anyone with cranking problems multi-weight (vis) would be the obvious route to take. After the electrical system including the starter was checked. Trucks make great use of 15W-40. Unlike our boats the truck engine is hang'in out there in the cold. If it's 10 degrees out the engine will be 10 degrees whereas our boat engines almost never get below 50 degrees in the water w a small bit of electrical heat in the engine compartment.

Cold weather starting was the reason for the emergence of both multi-vis and synthetic oil. The latter was a military endeavor to start engines in the Arctic in the winter. Just wouldn't crank at -40F.

 

[Tom.B]

I think the multi-vis will be fine. While you're at it, get a sample from each engine analyed.

That would be a neat trick...
(psst... I only have one)

Is there any chance of increased leakage from thinner oil?

 

[RT Firefly]

Greetings,
Rotella T. Straight 30wt year round in the Lehman's. As recommended in the manual. What does Perkins suggest? I'd go with that myself.

 

[CPseudonym]

Is there any chance of increased leakage from thinner oil?

Getting tired of the Perkins patina?

 

[jleonard]

The Perkins enignes often leak out of the starboard forward engine mount studs. The one I had was leaking badly until I heard about this phenomena. There are 3 studs and you can remove them one at a time, clean them off and reseal them with RTV of your choice. If you do it one at a time it will not affect engine alignment.
Mine was leaking to the order of aabout a quart every 8 enigne hours. I did this resealing job (less than 1 hour's work) and the leaking stopped completely.
I had also changed to Castrol 20-50 oil (that was ONE of the recommended oils in my operators manual) and ran that for the remaining 8 years I had that engine in the boat.

 

[O C Diver]

I tend to follow the engine manufacturers recommendation or possibly second the engine rebuilder. Another vote for Rotella T; really like that stuff for all my applications.

 

[Blue Heron]

I use 15w40 in my Perkins. Previous owner used the same for the past 10 years. Florida. Works well

 

[Tom.B]

Yea... even though the book says 20W20 for 30-80 degrees and straight 30 for over 80, I might just stick with Rotella 15W40 this time. If for no other reason than it seems to be the far more common weight carried across all retailers - both marine and auto.

 

[psneeld]

Yea... even though the book says 20W20 for 30-80 degrees and straight 30 for over 80, I might just stick with Rotella 15W40 this time. If for no other reason than it seems to be the far more common weight carried across all retailers - both marine and auto.

It's a more "modern" oil....probably designed for higher performance apps ...so why not?

I think my Lehman manual also talks about 20W20....not sure I have even seen it in diesel classification oils.

 

[Daddyo]

Tom,
I would run the SAE30 or 10W-30. Your rings/seals, etc are designed for the thicker oil. You should see less leaks and or oil consumption. As I've said many times I like the 10W-30 synth personally.

 

[Tom.B]

Tom,
I would run the SAE30 or 10W-30. Your rings/seals, etc are designed for the thicker oil. You should see less leaks and or oil consumption. As I've said many times I like the 10W-30 synth personally.

I am guessing this is a type-o? SAE30 or 10W30 is thinner than 15W40. Right?

 

[sunchaser]

Perkins for years has said 15-40. The smartest Perkins guy on the internet, Paul Foulston (ex Perkins and Cummins designer and builder) says the same.

 

[Daddyo]

I am guessing this is a type-o? SAE30 or 10W30 is thinner than 15W40. Right?

No, 30 is thicker then 40. The lower the second number the thicker in multi or SAE. The higher the first number the thicker ie:
10W-30 is thicker then 5W-30
10W-30 is thicker then 10W-40
SAE30 is thicker then SAE 40

 

[Daddyo]

Perkins for years has said 15-40. The smartest Perkins guy on the internet, Paul Foulston (ex Perkins and Cummins designer and builder) says the same.

The Perkins in my Westerbeke says SAE30.

 

[psneeld]

Motor Oil Viscosity Grades Explained in Layman's Terms

more detailed oil viscosity explanation

 

[Nomad Willy]

Tom B wrote;

"I am guessing this is a type-o? SAE30 or 10W30 is thinner than 15W40. Right?"

Depends on at what temperature. The 15W-40 is thicker at high operating temps and thinner when starting up cold. But at what temperature it gets as thick as 30W only the engineers know. There's no advantage to the MV unless one has trouble starting because of low cranking speeds. But the difference between 15-40 and 30W is really smaller than the numbers suggest. So which one is used makes so little difference (unless you can't crank the 30) that it's not worth talking about from an operational standpoint. Nobody would notice a difference running either one at operating temp but it can be said that there's more oil in the 30W as it dosn't have some oil taken out to make room for some stuff put in that has no lubrication properties or capabilities.

So I think it's safe to say that 30W is just a tiny bit better at running temps and 15-40W is a tiny bit better when starting cold.

Another thing to consider is that 15W40 oil is 15W oil. It's not 40W oil that flows like a 15W oil at low temps. It's a 15W oil that has stuff in it that reduces the tendency of the 15W oil to thin out at high temps. It's always thinner than 15W oil when running but at high operating temps the 30W oil will be slightly thinner than the 15W-40. So if the abilities of the stuff put in to prevent thinning dosn't perform at a 100% level after a time you may not have 15W-40 oil but 15-20 or 15-30 or just 15W oil if the VIs wore out all together. In the past the vis improvers wore out quickly so one soon had 15W oil. I've heard this problem has been solved but to what degree I'm not sure.

In my cars I never use 10W-40 but I do use 10W-30 as it has much less vis improver in it. I'm guessing it probably takes 3 to 4 times as much VI to bring 10W-30 up to 10W-40. It could be a linear function but I doubt it.

Just read your link psneeld .... very excellent having learned several things.

 

[RT Firefly]

Greetings,
Mr. D. Your explanation of multi-grade oils is correct to a point but in single grade oils SAE 30 is thinner than SAE 40.

 

[Keith]

Go with da book...30 W.

 

[Marin]

No, 30 is thicker then 40. The lower the second number the thicker in multi or SAE. The higher the first number the thicker ie:
10W-30 is thicker then 5W-30
10W-30 is thicker then 10W-40
SAE30 is thicker then SAE 40

Don't think that's correct. Read the link psneeld posted. The higher the viscosity rating, the greater the "thickness."

 

[Marin]

Motor Oil Viscosity Grades Explained in Layman's Terms

more detailed oil viscosity explanation

Thanks much for posting that link, psneeld. I learned some things.

Eric-- Did you notice psneeld's link addressed the isue of viscosity aditives encouraging the formation of sludge in multi-vis oils? I suspect this is the same issue you alluded to in one of your earler posts .

 

[Wxx3]

All,

A good discussion that summarizes all we've elarned in the last 50 odd years.
THe issue of viscosity extenders was an issue and to a certain extent, still is.

What has changed recently (last 10 years) is the understanding that much of your engine wear actually takes place in the first few seconds of engine start when the bearings have the least lubrication. Therefore, having a thinner oil when cold has become far more important than a thicker oil when hot.

The solution to the viscosity extenders problem is to simply change your oil more often.

just my two cents.

Richard

 

[Nomad Willy]

Marin,
Yes I did and as good as it is it's still a promotional text oriented to convince people they should buy Amzoil.
Talking about rubber aditives that turn to sludge is intended to make the Amzoil look look like a far better product. Amzoil was the only synthetic product lubricant that failed in ultralight aircraft in the early 80s. By failed I mean that numerous pilots had problems w it. I used/use a synthetic lube for 2 strokes that is not compatible w dino oil. It's so "thick" or viscus it says on the bottle not to use it on engines w auto oil injection lube systems. One thing all the engineers agree on is that thicker oil gives greater protection from wear. One must pre-mix it and mix it well as it dosn't mix as readily as dino oil that even has an additive to promote it to mix w gasoline. That's probably because of the guys that just dump the oil in the can w/o mixing.

And Marin yes I was previously "alluding" to the disadvantages of multi-vis oils but my complaint is that the additives are not lubricants and the more additives added the less oil is in the oil. Less oil to lubricate your engine. I don't know how much volume or weight of oil is displaced by additives and I want all the additives that I need to be in the oil. But I don't think we need VI improvers in our boat engine's oil. Just like you don't need multi-vis oil in your car in Florida or California. But in the winter in Minnesota you better have it. Probably 5W-60 if you can get it.


Wxx3 wrote;
"What has changed recently (last 10 years) is the understanding that much of your engine wear actually takes place in the first few seconds of engine start when the bearings have the least lubrication."
I think I've heard that for much longer than 10 years and I think FF alludes to that too. It may be but even in your words "is the understanding" there is a hint of believing that it most likely is more like a probability than a fact. On that one I think I'll need some scientific testing to make it fact in my book. But I buy into that enough to want to crank my engines a bit at least every month or so. Can you think of an application of engines that fail unusually often from "dry" start-ups?

LOOK AT THAT! THERE IS AN AMSOIL ADVERTISEMENT THAT APPEARED JUST TO THE UPPER RIGHT ON THIS PAGE. By that I learned to spell Amsoil correctly.

 

[boatpoker]

My Perkins ran on Rotella 15W40 (packaged in Ontario)since 1971 and on our first trip south (2001) I loaded up on Rotella. I replenished my stock in Florida (label said packaged in Texas) and at the next oil change started blowing brown smoke.
Yeah brown ! when I looked in the bottom of the container there was a visible brown sludge in the bottom.

After returning to Ontario I contacted Shell head office and was told that each refinery had their own formula, that they had no control over the Texas refinery and they refused to look in to the matter or look at the sludge in the container. This pissed me off so much that I switched to Delo.

I now dipstick every container before I put it in my engine.

 

[Tom.B]

I now dipstick every container before I put it in my engine.

Good advice. Thanks.

 

[Nomad Willy]

Greetings,
Mr. D. Your explanation of multi-grade oils is correct to a point but in single grade oils SAE 30 is thinner than SAE 40.

RT did I really say that ........ bad man. I should be punished or forgiven. But you said "Mr D" so it may not be my doing.

Tom B re your original post after all I've said I think you should use SAE 30 but I don't think you'll notice any difference. 15W40 is very recommendable and w the huge numbers of people using it in your application you should feel very comfortable w that choice.

Poker, I think you got some contaminated oil and if you live to be 997 years oil it almost certainly won't happen again.

 

[Marin]

RT did I really say that ........ bad man. I should be punished or forgiven. But you said "Mr D" so it may not be my doing.

No worries, Eric. So far as I know you did not say that 30 wt is thicker than 40 wt in any of your posts. Daddyo said that in one of his posts. Given his experience my guess is it was a typing mistake.

 

[Daddyo]

I did type that !! Sorry but the hands were working faster then the brain.