View Single Post
  #15 (permalink)  
Old 03-28-2014, 08:37 PM
bobcowan's Avatar
bobcowan bobcowan is offline
CC Member
Visit my Photo Gallery

 
Join Date: Feb 2007
Location: Colorado Springs, CO
Cobra Make, Engine: Backdraft, supercharged Coyote
Posts: 2,445
Not Ranked     
Default

Quote:
Originally Posted by dan512 View Post
I checked and I can get Valvoline VR1 over here in 20W-50 and 10W-60.

I'll give it a try mixing both, should end up with an 15W55.
That is definitely a bad idea.

During start up, a thick oil like 15W or 20W will not lube your engine very well. You've probably heard that the majority of engine wear occurs at start up; and that is generally true. Thicker oil when cold will make that worse.

Viscosity of oil is measured at a standard temperature. a 5W oil will pour like 5 weight oil that's been chilled below 0*. So buy a quart of 20W-50 oil, and put it in the freezer. In the morning, try and pour it out.

Thicker oils when hot do not provide any additional benefit in longevity or performance. The do require more energy to move around, and put more strain on components like oil pump drive shafts and distributor gears. You've heard of people shearing the gear pin, and this is how it happens.

You need a thick enough oil to maintain proper oil pressure in all conditions. Anything more is a waste of energy. Start with a 5W-30 and see what you get. If you're dead set on a heavy oil, use a 5W-40 or 0W-40.
__________________
.boB "Iron Man"
NASA Rocky Mountain TTU #42
www.RacingtheExocet.com
BDR #1642 - Supercharged Coyote, 6 speed Auto
Reply With Quote