Hi guys, I have read that some guys have been using Mobil1 foreign car engine oil 0w-40 in their street rods. Can this really help with cutting friction and wear then starting a cold engine or is it putting the engine in harms way? It would get the oil to the bearings and moving parts faster and still have the higher viscosity when warmed up. Should I change to 0w-40 or stay with 5w-30?

 

Where do live? If it's -40 in the morning vehicle sitting outside with no block heater it may help but other wise 5-30 should be fine.

 

Stick with the 5W-30 at minimum, especially if the Engine has some miles on it.

 

Agreed. There's NO benefit to the thicker oil except eye candy (making the gauge read higher) aka wandering off the path when distracted by shiny things. Bearings don't give a rat's *** what the oil pressure is. All they care about, is OIL FLOW through them. You could pour candle wax into your motor, and the gauge would read off the scale, butt I doubt the bearings would like it. A continuous supply of clean oil, at enough pressure that the crank surfaces never touch the bearings, is "enough". Just take a look at the Super Stock guys that run the smallest oil pump they can find and circumcize the spring to reduce the pressure; the reduced pump load (parasitic) on the engine frees up acoupla .01s of HP, as long as there's "enough" that the motor lives. The thinnest oil you can run while maintaining "some" pressure is always best.

 

Thank you @LS1 TJ for your opinion, it does make sense. I may stick with 5w-30. I don't live in a cold climate (Northeast, US) and only drive in the summer. Thank you again and have Merry Christmas and a Happy New year.

 

Thank you for the reply @LS1 TJ. My engine has 140K on it, I probably will just stick with 5W-30 and don't try 0-40. Thanks again and have a Merry Christmas and a Happy New year.

 

RB04Avnl thank you for the reply. I always read and hear about the high oil pressures they run. It does make sense that's all you need is enough oil to get the job done, more is is not always better. Thanks for your input and have a Merry Christmas and a Happy New Year.

 

If you're below zero, I'd recommend 0w-30, otherwise 0w-40

 

Higher than OEM oil pressure does nothing but rob power and aerate the oil. I have piston oil squirters that bleed off some pressure. I see about 50lbs, give or take a couple psi when hot at 7,000 rpm. 50,000 miles on the bearings, no issues. People who run more than 55lbs-60lbs are wasting a small amount of power, and also increasing oil temps slightly, because forcing oil thru a small orifice at higher pressures than needed will also increase oil temps a small amount. I have to admit I was very surprised at the like new condition of my cam bearings when I installed a new cam this past summer. No copper showing at the bottom of the bearings, which I did have on my Darton sleeved 427 after 30,000 miles. So, so much for "needing" 70lbs, or more, of oil pressure like some guys may think......