Oil Question
 

Why is "Marine Oil" 20w 50 or 25w 40 or such. Why not 10w 40 or 15w50. I understand the second number higher being better for long high rpm runs but whats with the first number. I would think lower is better. Less time to get the oil pumping.

Chris

Actually for a boat, the first set of numbers really don't apply to us......that's the rating for cold weather operation...since we don't boat in winter conditions the second number is what you should be looking at ....
The "W" incidentally stands for winter....so like i said...don't really apply to us. :)

A while back I switched over from standard merc 25w40 to Rotella T5 Semi Syn 15w40 in a stock Merc SBC. I seemed to have found 100 RPMS doing this. I know it sounds like BS but it has been a consistent result for me. So far no problems. Anyone see any drawbacks to this oil. I'm sure there is better oil out there but this is a stock merc SBC. It see's 70% of its time 1000 RPMS and 30%of its time at 3800-4000 rpms with a run up to 4400 rpms for about 1 min each time we go boating.

Chris

I have found some extra rpms with heavier oil...but I am opposite of you, I run the piss out of mine.

I just look at WOT performance, not lower rpm.

Example: Going for a WOT run this past week-end my sbc was at 6200rpm. Hydraulic roller.

So, in my case, even though some disagree, but I'm old and have run the schit out of many valvetrains, my hydraulic and hydraulic roller engines are more stable at higher rpms with thicker oil .

In your case, there is no valvetrain hydraulic issues to worry about, therefore your results are from reduced fricition. And yes, this can happen between oil brands, and more typically oil weights and synthetic vs non.

The reason why so many car manufacturers use syntetic drivetrain oils is because fuel mileage. Plain and simple.

Ahhhh, another oil thread, just one comment, You wont find me running a Diesel oil in my marine engines :argue:

And now I am explaining on almost a daily basis to customers about oil consumption. Between 10K mile oil change intervals, low tension rings, and 0W20 piss-thickness oil, yeah, your little high revving 4 banger is going to use a couple of quarts. The unwashed masses are having to learn how to check the magic wand under the hood every now and again to see how much oil is in the motor.

Wanna know how I stopped having to explain ?

No more 5W20...they get 5w30. And 3-5k oil changes. Synthetic 5k, regular oil 3K. Most come in at correct time.

Only vehicles I have that use oil / have low oil issues are old POS Subarus that should be thrown out soon for other issues. LOL.

So what do you run 33 outlawsst. I know lots of people running Shell rotella T.. Not sure about the T5. Anyway I am just looking to see if there is anything wrong with the T5 or 15w40. My Main reason is they sell it at Oreilly and Orilley also has the filter I use which is a wix 51515. And I'm sure that is a whole nother debate. I dont have a bone in that fight its just convenient for me and I want to make sure its ok for my motor.. Has been so far. Maybe Oreilly will start carrying Brad Penn...lol... Just kidding.

Chris

http://www.walmart.com/ip/Mobil-1-15...5-qt./20713647

4.78 a quart and free shipping if you order more than one is pretty hard to beat for full synthetic.

I thought the first number was for "summer" weight and the higher (Second number) was for winter weight. Colder temps meaning thicker oil. Am I wrong? 15W40 in winter temps would be 40 weight

Never mind. I got the good ole Google answer. Just to think how long I was wrong about oil weights. Who knew.

Valvoline VR1 Full Synthetic Racing Oil 20W50

The bigger the difference between the Winter designation and Summer like a 5W50 the more friction modifiers have to be put in . Friction modifiers turn to $hit and the oil suffers.

This guy can explain it better:

https://www.youtube.com/watch?v=E_iN_IJpSIU My most recent experience with Mystic and mobil 1 15W50 is that when I change the oil it comes out thin as water so I switched

I really liked the straight 50 weight Brad Penn I used this weekend, we`ll see what BlackStone labs will say about it after I get some more hours on it.

I'm thinking of trying some mystik 15-40 but still have a case or two of VR1 straight 50 to use up. Anybody running that 15-40 mystik?

Valvoline VR1 20-50 Full Synthetic , if its good enough for my JD-345 with the 60" deck and the liquid cooled Kawi 20hp thumper its good enough for the 540's :bunnydance::bunnydance:

Mild Thunders oil pressure with Mystic was down too.

^^ I reread that. Got it now. VR1 is where I'll stay

Yep. Fresh 15w50 Mystik. After a hard run, oil temp around 190ish, at idle, in gear, oil pressure was 20-25psi. Changed it out, for 20w50 VR1 Synthetic in that engine, same scenerio, oil pressure was 30-35psi.

I have those oil drain hoses that hook to my oil pans. Using my little jabsco drill pump, engines had been sitting for a week, I was able to suck out 9 quarts from the pan, in no time at all. Mystik was coming out like water. had not even 10 hours on it.

In Michigan it can on some mornings! :)

Appreciate you sharing that. Real world firsthand experience.

curious what changed, suppliers, manufacturing, or what as I remember you touting their oils . At any rate thanks for the updated info, I'll be sticking with the vr1 I guess.:ernaehrung004:

Im still running their gear oil in my drives. I believe mystik fluids are citgo.

that is correct they are Citgo all made by them. Citgo makes a lot of OEM marine oils as well. More so years ago but still has a lot currently with the OEM marine engine manu's.

The best thing to do with your oil is have an oil analysis done. But you need to check out how well they can do this, so test them.

I have done this in the past, take 2 samples to be sent off to them. Just fill your sample bottles one right after another from the same oil drain. You send one off with your info and have your buddy with a different address and 2 days later send in the other same sample. Guess what do not be surprised if your 2 samples comeback with totally different results. I have done it and the results were not the same - some not even close. . Time to test another analysis company with the same test. The day your oil samples come back exactly the same that's the company you want to use. Test your oil analysis company. Been there, done that.

What position is best to check oil level, on trailer level ground or in water, sitting still? Maybe its 6 and half dozen????

I prefer to check mine in the water. Depending on how the boat sits on the trailer affects the oil level.

Makes sense as Baja customer service rep said static in the water is best time to assess fuel level. So, seems fluid measurements are best taken in the water...since that is the boat's actual/operating environment...

I check the oil level when flat. Then mark the dipstick. This will be a reference for when sitting in the water.

You don't want to add more oil than the pan (flat) disctates. Having the rear (or any) of the crank turning in oil will foam it.

Furthermore, One of the big advantages to having a large capacity oil pan, is so that you can run less than it calls for. Keeps the chance down of submersing the crankshaft.

One of the reasons to blend and recommend a 25W40, it is cheaper to make. You need less polymer to make the oil a multi-viscosity product.

Friction modifiers do not shear, polymers do.

Ken

Right on the money... after putting 10 qts in my 10 qt pans the oil line was at "add" not "full"