what oil weight do you use?

-
Just started using straight 40 weight Valvoline racing oil with zinc.

I may be all wet here, but it was always my understanding that multi grade oils were engineered to maintain their viscosity from cold to hot. For example, 10w40 the viscosity of the oil is 40 at start up and 10 at normal operating conditions.
 
Ramcharger caferacerx; thank you so much for your explanations for this big dummy over here! Like now I fully understand atleast I think. So, If im running a beat up 360 street engine down here in georgia, what shuld I run? 20w50? 15w40? just wondering. Thank you all for ur explanation and sharing what oil weight you use when.
 
15w-40 or 10w-40 should be a good compromise. The new 15W-40 truck oils used to have plenty of zinc phosphate additive but that has now gone away. If your bearings are about shot 20w-50 may work for you for awhile but if it gets much below 60F, I'd change back to the 15W-40.
 
My engine builder turned me on to Shell Rotella 15w40 as a break in oil and I have continued to use it, he explained this oil has all the ingredients in it a motor will ever need and after 40 years of High performance engine building how could I question his success.
 
DUSTERDOWNS said:
My engine builder turned me on to Shell Rotella 15w40 as a break in oil and I have continued to use it, he explained this oil has all the ingredients in it a motor will ever need and after 40 years of High performance engine building how could I question his success.
Click to expand...

Used to have. the zinc is gone now.
 
When did htey take the zinc out? I have 4-5 gallons here that I have had for about 2 years. I had planned using it for when I break in my 360. Now wondering what I should go with. Maybe just get the zinc additive and add it to it?
 
I used SAE 30 for the break in of my pumped up 318 and then I drained that oil out and swapped to another new filter and used Royal Purple 5 w30.

I contacted royal purple and asked them what was best for my combo and my year and style engine and so on and they said they highly recommend the 5 w30 royal purple because it is specially blended with certain additives other oils lack and is designed to work with a flat tappet cam.

so thats what I went with
 
deisel oil 15/40 use to have about 1400 ppm of zinc but they have scaled back to about 1200ppm, still a lot more than pass car oil, its fine for a cam with moderate spring psi like a single with dampner of 120 seat and under 300 open like many warm engines might have. When you get into double springs and higher spring psi than you might want to run a race oil like valvoline "not for street use", royal purple, or brad pen that has the 1400/1500 ppm or use a zinc additive with the 15/40.
 
Working at the Ford dealship LOTS of guys ran 0-40 in their powerstrokes they turned over and fired so much better on a -20 to -30 day. Not a cheap oil change when you need 14liters of it though.

In school we watched a cool video on pour rates and at -20 10w-30 is so thick already it's nearly molassas but at the same time the pour rate of 10w-30 synthetic was better at the same temperture due to the engineering of it and the wax being gone.
 
You must log in or register to reply here.
-

Back
Top