what oil weight do you use?

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good question. My answer is also, I've never seen a 0 weight on the shelf, then again, I never looked for it ethier.

In the new engine build, it's a 5-30.
 
I'm using 0W40 Mobil One. The 0W only applies when it's cold, it's thinner than the 10W at cold temp, but still thicker than at operating temperature.
 
0w 30 is used in mostly Euro cars (BMW, Benz, Etc.) is a step up from 5w 30. The W means winter weight so it means that the oil with flow quite easy in extreme cold.
 
Unless you are starting your car at or below the freezing point the first number in a multi-grade oil doesn't mean much. Up north here the 0W30 and 5W30 weight oils are good for the cold starts. I even have some 0W40. I wouldn't want to run the 20W50 in the winter!
 
1MeanA said:
Unless you are starting your car at or below the freezing point the first number in a multi-grade oil doesn't mean much. Up north here the 0W30 and 5W30 weight oils are good for the cold starts. I even have some 0W40. I wouldn't want to run the 20W50 in the winter!
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well, Im wondering what the last two digits mean as well too. Like when shuld I use W30 W40 W50? like in what situations. Im sorry, just wanna learn alot more about this, I just know when to change my oil and how to LOL
 
1MeanA said:
Unless you are starting your car at or below the freezing point the first number in a multi-grade oil doesn't mean much. Up north here the 0W30 and 5W30 weight oils are good for the cold starts. I even have some 0W40. I wouldn't want to run the 20W50 in the winter!
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Had a 455 in a Pontiac Lemans that would start in the dead of winter in NJ with straight 90 weight gear oil in it. Even with the gear oil in it adding a quart every 200 miles was normal. It did not leak a drop of it neitherdisgust
 
I use a straight 30 weight HD from Valvoline with zinc additive.
 
DarTT said:
well, Im wondering what the last two digits mean as well too. Like when shuld I use W30 W40 W50? like in what situations. Im sorry, just wanna learn alot more about this, I just know when to change my oil and how to LOL
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I've run both a 10w30 and 10W40. I wouldn't run a W50 weight except in high heat/competition use.
 
inkjunkie said:
Had a 455 in a Pontiac Lemans that would start in the dead of winter in NJ with straight 90 weight gear oil in it. Even with the gear oil in it adding a quart every 200 miles was normal. It did not leak a drop of it neitherdisgust
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You're kidding right? :???:
 
Nice tight clearance motor 5w30 or 10w30, looser or older motor 10w40, used for racing 20w50.
 
Go to the Joe Gibbs racing oil website for more 0 weight oils. Seems the Nascar boys run those thin oils for qualifying.
 
StrokerScamp said:
I use a straight 30 weight HD from Valvoline with zinc additive.
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X2 the last time I used a split wt. oil I lost 10psi.oil pressure.I have always run my motors lose.like 3thos.clarence on the crank mains and rods.there is no brake in on my motors.wen they fire and get wormed up they get shut down cooled off heads get retorked valves adjusted and there race ready.I have never lost a bottom end I believe in strate wt.oil 30 in the winter 40 or 50 in the summer. sorry for the long input but that's my thoughts on split wt. oil......Artie
 
StrokerScamp said:
I use a straight 30 weight HD from Valvoline with zinc additive.
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X2 the last time I used a split wt. oil I lost 10psi.oil pressure.I have always run my motors lose.like 3thos.clarence on the crank mains and rods.there is no brake in on my motors.wen they fire and get wormed up they get shut down cooled off heads get retorked valves adjusted and there race ready.I have never lost a bottom end I believe in strate wt.oil 30 in the winter 40 or 50 in the summer. sorry for the long input but that's my thoughts on split wt. oil......Artie
 
DarTT said:
like I see heavy duty roots blown engines use come crazy weight gear oil. So would u run w50 on a turbocharged engine?
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Can't make that call. The lighter oils are good for cold starts and reduce friction (hence the use in qualifying) and the more viscous oils (like 70 weight) are used where extreme temps or might loads are encountered. If you run an oil that is too light/low viscosity you run the risk of partial film lubrication which will cause bearing damage and cylinder wear.
 
All oils get thinner as they heat up. They start at the higher viscosity. that's why pressures typically go down as the engine heats up and theoretically get tighter. 0-30 is IIRC factory oil for Ford products, where most others are still at 5wt oils. lower viscosity means less protection in most cases, but the oiling systems, clearances, and materials in modern engines are very different from what the old things have. Unless it's a race engine with very careful attention to detail I would not use a 0 or 5 wt oil in them. I typically run 15-40 in everything, but if it's a fast rate flat tappet and street car, I use straight 30wt (not for street use) VR-1.
 
moper said:
... lower viscosity means less protection in most cases, but the oiling systems, clearances, and materials in modern engines are very different from what the old things have....
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Very true. Oils for new engines are designed for low emissions, efficiency and roller engines. We're not concerned much with any of those.
 
DarTT said:
I keep hearing straight 30 weight? whats this mean 10 w30
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Maybe I can clarify this for you. 10W-30 act like a straight 10 weight oil when cold and a straight 30 weight oil when hot. 20W-50 acts like a straight 20 weight oil when cold and a straight 50W oil when hot, etc.

Cam manufacturers used to reccomend using a straight weight oil when breaking in the cam back in the day. Their reasoning was that multi-viscosity oils require additives that modify the flowability (viscosity) of the oil and those additives don't help the anti-wear properties (lubricity) of the oil. BUT, in a street car that has to run in a gamut of tempratures, the need for multi-viscosity oil overrides the minor loss of lubricity.

If someone were to run 20W-50 or straight 40 or 50 weight oil in a tight bearing clearance engine on a 10 degree day, the engine would eat it self up on start up. That stuff turns to syrup on cold days and I've seen people sieze a valve in the guide doing this exact thing and sure enough, in a less than a year they have to replace rod and main bearings.

On the other hand, in a loose clearance racing engine running a light 10W-30 oil is a bad idea. The oil film is not tough enough to withstand the high heat and pounding of the rod and mains.

The 0W oils are really for super tight clearance new engines. They have very low pumping losses and increase hp output and help with fuel mileage at cruise.

There is a school of thought that running a loose racing engine with a HV oil pump and the new synthetic 0W oils will reduce windage, pumping losses and still provide the oil film toughness and lubricity needed to prevent the engine from self-destructing. I can't comment on that as I've never tried it but it make sense.

The zinc additive thing is a whole different thing and has been beat to death here. Let's just say that it is no longer put in most oils, if you are running a flat tappet cam you have to have it whether it's a poured in additive or blended in at the factory.

Having said all this, I use 10W-40 in the summer and 10w-30 in the winter in all my flat tappet tight clearance street engines. In the loose clearance engine I'm building now, I'll run 20W-50 VR race only stuff. I prefer Valvoline in all my engines and use the Hughes Engines additive only because I can't find Valvoline VR locally in the weights I want.

I hope this answered some of your questions.
 
the difference between a mono grade oil "SAE 30" for example and a multi grade oil like "SAE 10W30" can be a bit confusing, that is because the mono grade oil (like straight 30 weight) CHANGES viscosity as it heats up, and multi grade oil (like 10W30) stays a more consistent viscosity,
its not as some would believe that multi grade oils are thinner than straight single weight, but that single weight mono grade oil gets THICKER WHEN IT GETS COLD, straight 30, and 10W30 are both the same thickness (SAE 30 weight) in an engine at operating temperature,
the big difference occurs when the engine and oil are cold, the straight 30 weight oil gets very thick and does not flow very well, the oil pump must work harder, any areas that rely on splash lubrication suffer, all leading to excess engine wear until the oil warms up,
multi grade oil like 10W30 do not have that problem, when 10W30 gets cold it is only the thickness of 10 weight oil so it is much better at lubricating your engine leading to much less engine wear at start up


hey you beat me to it!
good explanation ramcharger
 
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