Motor Oil: 10W30 or 20W50

[Schulmann]

I am wondering about the right viscosity and not about the brand !

I have done a couple of research on this matter and my findings are stunning.
In the past I though that running on a thinker oil is better. However it might not be the case ...

Read this regarding viscosity:
(All brands have nearly same viscosity)

10W30
=====
Viscosity at 40C 65
Viscosity at 100C 10
CCS 4000
Flash point 230C
Pour Point -50C


20W50
=====
Viscosity at 40C 155
Viscosity at 100C 18
CCS 5000
Flash point 250C
Pour Point -40C


The 20W50 oil it is obviously two times thicker. Using this motor oil, my engin will generate more friction thus I will loose HP. My engin won't run hotter since the cooling system will compensate. Also my engin will ware quicker.

The only case when this 20W50 oil might be better instead of the 10W30 oil, is when the oil`s temperature goes up to 120C (250F). However above 250F all oil tends ti loose its qualities.

I conclude that the best is to stick to the 10W30.
Am I right ?

 

[martyb]

Schulman,

I have been wondering the same thing. I am using 15-50 Mobile 1 in my Roe S/C Gen 1. I am wondering if I should use 10-30 to free up a few HP.

What is everyone else running in their S/C cars?

 

[Joseph Dell]

IMHO, Mobile 1 10-30 syntehtic is a rather good oil. The only time to step up to a thicker oil is if you change your rod bearings to something other than stock... like, say, a chevy bearing. An offset ground crank may use chevy bearings which requires a thicker oil b/c the tollerances are there but not _quite_ the same as the stock. so your oil pressure may drop.

a 50 wt oil will compensate for that.

Just my .02...

JD

 

[PHILIP]

From what I have just learned Mobil1 0w40 is supposed to be their best oil, 10w30 is not commonly available here in New Zealand

Regards Philip

 

[Hoosier Daddy]

I was told to go half and half.