Kinematic Viscsity above 100 C

[Daveonsub]

I have a HD with an air cooled V-twin 103 cu in engine. Therecommended grade of oil is 20W-50. All the product data sheets provide the kinematic viscosity at 40 and 100 C. What would the kinematic viscosity be when the oil is at normal operating temperature? I assume the normal operating temperature is around 250 F.

 

[alarmguy]

100 celsius = 212 degrees F

I would think 250 degree temperature would be in traffic conditions. Im sure on the highway you would be 210 to 230 max assuming you have an oil cooler on the 103 which I think all do?.
I have a 14 Road King, but dont have a temp gauge yet. So I am only guessing.

Harleys are designed for 20/50 oil. No concerns about being to heavy. *L* But I dont know the answer to your question exactly. Im sure someone here will. I did google it, there are some charts but only up to 100C

 

[A_Harman]

Viscosity above 250F can be calculated. What are the 40C and 100C viscosities of the oil you're using?

 

[ARCOgraphite]

A_Harman will help you, but, Do you want to run a larger oil cooler and jump to a lower grade? Or is this just a thought exercise?

 

[BrianC]

Originally Posted By: Daveonsub
I have a HD with an air cooled V-twin 103 cu in engine. Therecommended grade of oil is 20W-50. All the product data sheets provide the kinematic viscosity at 40 and 100 C. What would the kinematic viscosity be when the oil is at normal operating temperature? I assume the normal operating temperature is around 250 F.


250 F is 121 C. The typical 20w-50 would be a cSt viscosity of 12 to 12.5 at that temperature.

http://www.widman.biz/English/Calculators/Operational.html

Insert your 40 and 100 viscosities, enter 121 as your operational and hit calculate.

 

[BrianC]

Originally Posted By: BrianC
Originally Posted By: Daveonsub
I have a HD with an air cooled V-twin 103 cu in engine. Therecommended grade of oil is 20W-50. All the product data sheets provide the kinematic viscosity at 40 and 100 C. What would the kinematic viscosity be when the oil is at normal operating temperature? I assume the normal operating temperature is around 250 F.


250 F is 121 C. The typical 20w-50 would be a cSt viscosity of 12 to 12.5 at that temperature.

http://www.widman.biz/English/Calculators/Operational.html

Insert your 40 and 100 viscosities, enter 121 as your operational and hit calculate.


As an example, using Amsoil's 20w-50 MC oil (150.3 @ 40C, 20.1 @ 100C) the operational viscosity at 121C would be 12.68cSt.

 

[Daveonsub]

I have a 2012 RKC it does have an oil cooler. I was just guessing on the oil temp. I don't have a temp gauge, but have seen on HD Forums people reporting 220 - 250

 

[Daveonsub]

Brian,

Thanks. Gave me all the info looking for

 

[Daveonsub]

just curious

 

[benjy]

i believe better oils thin less at higher temperatures. there are places within the engine that get very hot, that said Redline's ester oils handle the most heat while protecting your engine, its expensive but cheaper than any engine work if you intend to keep your bike a while

 

[mjoekingz28]

What about the HTHS viscosity @150C (302F)?

Would that be applicable?

 

[widman]

posted in wrong place. Delete