How much difference does 10 Centistokes make?

[Merkava_4]

Maxlife 10W-30

75.0 Centistokes @ 40C
11.5 Centistokes @ 100C

Maxlife SAE 30

85.0 Centistokes @ 40C
11.4 Centistokes @ 100C


How much difference in cold start wear is there between 10 Centistokes ?-?-?

What would you say the difference in Centistokes is between these two oils at 35 degrees Fahrenheit ?-?-?

 

[bruce381]

Hard to say thicker at cold will SLOW flow to top end and cam so higher vis should/would/could have higher startup wear.
bruce

 

[XS650]

There are some viscosity calculators online where you plug in the vis at 3 temperatures and they calculate the vis at a 3rd temperature that you select.

Mr Google will find them for you if someone else doesn't come by soon and tell you where one is.

 

[bruce381]

and the problem is not at 40c which is about 102F the problem is vis at 50F or so then most any oil is way to thick and only protection till presure and flow is up is from AW additives and thin oil film that gets wiped off fast. that is why a 0w will be best for fast flow.
bruce

 

[bruce381]

problem is not thick oil on journol but LACK of oil flow a thick cold oil will lube very well but does not repelenised fast enough before metal to metal.
bruce

 

[Curious Kid]

Oh such delicate balances...

 

[Dominic]

40C ain't cold

 

[Lonnie]

Viscosity is not the only measure for how an oil will protect your engine at startup.

 

[Merkava_4]

^
Okay I give up; what are the other attributes that contribute to an oil's ability to protect an engine during cold starts besides low viscosity?

 

[yannis]

polarity

 

[Tempest]

And the anti-wear films that have built up ON the metal. This is where additive quality/quantity come into play.

 

[Drew99GT]

Centistokes, or kinematic viscosity doesn't tell you pretty much anything at super cold temps. That's why the SAE uses cold cranking and cold pumping tests to determine how an oil will actually behave going through an oil pump and through an engine. That's why, by definition (since the "W" ratings of various oil weights are measured via cold cranking and cold pumping tests), you can use 10w-30 safely to -13 degrees F as -13 is where the 10W cold cranking test is performed. -13 and 10w-xxx wouldn't be preferred, but you could make it fine and not cavitate an oil pump or kill an engine.

 

[TallPaul]

Too bad they don't have cold crank and cold pumping stats for the straight wt. It would be interesting though to see what the cSt difference is betten the 10w30 and the SAE 30 at say 0F and 32F.

 

[Drew99GT]

At 0 degrees F, Maxlife 10w-30 is 3,556 Cst; at 32 degrees it is 753 Cst.

Maxlife SAE 30: 0 degrees F = 6,225; 32 degrees F = 1,086

That's pretty significant. But in a mild climate, say 70 degrees..........SAE 30 is 235 Cst, 10w-30 is 190 Cst. Not much difference. 5w-20 Maxlife at 70 degrees is 122 Cst. If the temp is 85 degrees, 10w-30 is the same viscosity as 5w-20, so at mild to warm/hot temps, I'll take the beefier, thicker oil thank you because starting temp viscosities are so close it's there's no meaningful difference. But if your oil gets to like 250 or above working hard up a mountain pass, I'll "pass" on the 5w-20.

 

[Mudcat]

Quote:

---

-13 and 10w-xxx wouldn't be preferred, but you could make it fine and not cavitate an oil pump

---

Drew
What is the relationship between oil pump cavitation and vicosity?

 

[Drew99GT]

Too thick to pump = cavitation generally speaking. I'm no expert on the subject, so others can chime in.

The oil pump bypass is designed to help mitigate this though.

 

[Merkava_4]

Drew99GT,

Thank you for the easy-to-understand explanations.

 

[Steve S]

Quote:

---

and the problem is not at 40c which is about 102F the problem is vis at 50F or so then most any oil is way to thick and only protection till presure and flow is up is from AW additives and thin oil film that gets wiped off fast. that is why a 0w will be best for fast flow.
bruce

---

Are you saying 30 wt oil takes too long to circulate at 50F ?

 

[flatlandtacoma]

Quote:

---

Maxlife 10W-30

75.0 Centistokes @ 40C
11.5 Centistokes @ 100C

Maxlife SAE 30

85.0 Centistokes @ 40C
11.4 Centistokes @ 100C


How much difference in cold start wear is there between 10 Centistokes ?-?-?

What would you say the difference in Centistokes is between these two oils at 35 degrees Fahrenheit ?-?-?

---

Maxlife SAE 30 ~ 950 cSt @ 35F
Maxlife 10w30 ~ 660 cSt @ 35F

Depending on what you call "cold", the difference probably means a lot more than the viscosity difference between Havoline 10w30 and Maxlife 10w30.

 

[XS650]

Quote:

---

Quote:

---

Maxlife 10W-30

75.0 Centistokes @ 40C
11.5 Centistokes @ 100C

Maxlife SAE 30

85.0 Centistokes @ 40C
11.4 Centistokes @ 100C


How much difference in cold start wear is there between 10 Centistokes ?-?-?

What would you say the difference in Centistokes is between these two oils at 35 degrees Fahrenheit ?-?-?

---

Maxlife SAE 30 ~ 950 cSt @ 35F
Maxlife 10w30 ~ 660 cSt @ 35F

Depending on what you call "cold", the difference probably means a lot more than the viscosity difference between Havoline 10w30 and Maxlife 10w30.

---

Right you are. at 26F the 10W-30 would be the same viscosity as the straight 30 at 35F

So if that particular straight 30 is too thick at 35F, then 10W-30 would be too thick at 26F, which we know to not be true.