GC in a 5.0 Mustang with 135K miles?

Messages
19
Location
Tallahassee
I currently run Valvoline Synth 20w50 in my 1995 Gt 5.0..... I'm doing alot of short driving now... So I'm thinking that GC 0w30 would be better.....because of the protection during startup.... Would the GC 0W30 be thinner than an Amsoil 10w30?
 

Patman

Staff member
Messages
21,989
Location
Oakville, Ontario
GC 0w30 would be thinner than Amsoil 10w30 on startup, but slightly thicker at operating temperatures. Amsoil 10w30 is around 11.7cst at 100c, while GC is around 12.0 to 12.2. Either one of those two choices should work out better than the thick 20w50, especially because of the short trips.
 
Messages
3,593
Location
Outside smalltown, IL
I say yes to the GC in your Mustang. I've been running M1 5W-30 in my 5.0L, and if I didn't want to try the new M1 0W-30 R when it appears I'd probably put the Castrol in it. Unless you're roadracing a much modified engine, I can't imagine wanting a 50 weight oil in a Ford small block...
 
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2,480
I will go out on a limb here and disagree. Here's why....unless it gets down to -20C or lower in Talahasee, the synthetic 20-50 will provide better protection than ANY 30 weight. Why? Because the film thickness is greater. Furthermore, the film thickeness will be greater on startup because a greater thickness of oil will be left on the parts than a thinner oil. This is enhanced as the temps. get colder and the trips get shorter. This is what I'm experiencing with the 10-60.
 
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5,785
Location
Dixie
If you try to protect a vertical surface by throwing a gallon of paint on it, how much of that paint does any good...? [Wink] Clearances between moving parts in a running engine are typically 5-20 microns. Twenty five microns = .001" or one "mil" For you Canucks who use that funny metric system: 1000 microns = 1 milimeter If you put a straight 60wt oil in your engine it will coat the valvetrain parts with perhaps 1/8" (about 3000 microns),of oil when it's cold. Not a bad idea for engine storage,but completely useless in any functional sense .... In the case of the valvetrain, wear protection is the result of a sacrificial layer of antiwear additives that is measured in hundreds of nanometers (1000 nm = 1 micron) - that layer is not visible at all to the naked eye ... [Roll Eyes]
 
Messages
3,593
Location
Outside smalltown, IL
quote:
Originally posted by Dr. T: I will go out on a limb here and disagree. Here's why....unless it gets down to -20C or lower in Talahasee, the synthetic 20-50 will provide better protection than ANY 30 weight. Why? Because the film thickness is greater. Furthermore, the film thickeness will be greater on startup because a greater thickness of oil will be left on the parts than a thinner oil. This is enhanced as the temps. get colder and the trips get shorter. This is what I'm experiencing with the 10-60.
If you were were really confident in the "logic" of this you'd be running a straight 50 or 60 weight oil year round instead of a 10W-60. Feel free to do that and show us the stellar UOA's it produces...
 
Messages
252
Location
AB, Canada
Here we go AGAIN... Thick vs Thin...the debate never ends... Tooslick...
quote:
For you Canucks who use that funny metric system
For you Americans, who, by the way, are the vast minority in this sense, use the completely irrational and downright silly Imperial system... [Mad] [Wink]
 
Messages
5,785
Location
Dixie
Geeman, I'm in violent agreement with you ... I work as a mechanical engineer and the metric system is vastly easier to use, once you get comfortable with it. Honestly, most of my comments are in jest ...I really like Canada - I can't understand why we don't just annex the whole place and outlaw Curling [Wink] Ted
 
Messages
2,480
No, not a straight 50 or 60 weight...might as well use grease...but since a 20w-50 will suffice down to -20C (according to some manuals - like mine), it will suffice just as well as a 0-30 albeit thicker. At temps below this, it's a different story. A 20-50 will be too thick to crank and subsequently flow in order to maintain adequate oil pressure. I only threw in my observation that the oil seems to cling better on parts than thin grades and this seems to be more the case the colder it is...just an observation...
 
Messages
252
Location
AB, Canada
Tooslick... Outlaw curling...!!! Why I outta...! Sacriledge.. The nerve...! Gasp...! Ok, I admit, its kind of a, ummm, goofy game... But so is NASCAR, the WWF (or is it just WF)of auto racing...!!! [Big Grin] [Wink]
 
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