lighter oil in winter

[guido]

CADplans is 100% correct.
My 127 is parked in an unheated attatched garage and I use 30wt year round. It has a hard time turning over in the winter. A magnetic block heater does the trick when there is snow in the forecast.
Guido

[cubs-n-bxrs]

Originally Posted by CADplans

Running these tractors for light duty, oil weight does not matter, multi weight oil is great.

The recommendations of multi weight oil should be used with the understanding of what you are putting in the engine.

10W-30 is 10 weight oil. 15W-40 is 15 weight oil. Period.

The oils have modifiers in them that can variably "thicken" the oil as the temperature goes up.

The thickeners are very effective up to a certain temperature, designed and perfectly acceptable for WATER cooled engines.

Above this certain temperature the thickeners fail, and, the oil reverts back to 10 weight (or 15 weight).

This is what happens in a air cooled engine under a normal load. The engine operates above the thickeners temperature capability.

You will be running your engine on 10W oil!!

The engine manufacturers state 30W for a reason.

They want your engine protected when under normal load conditions.

Run the oil you want, mine get 30W. IMHO

Your whole theory is backwards. This was taken off of the Amsoil website.
OK . . .What does a 5W-30 do that an SAE 30 won't?
When you see a W on a viscosity rating it means that this oil viscosity has been tested at a Colder temperature. The numbers without the W are all tested at 210° F or 100° C which is considered an approximation of engine operating temperature. In other words, a SAE 30 motor oil is the same viscosity as a 10w-30 or 5W-30 at 210° (100° C). The difference is when the viscosity is tested at a much colder temperature. For example, a 5W-30 motor oil performs like a SAE 5 motor oil would perform at the cold temperature specified, but still has the SAE 30 viscosity at 210° F (100° C) which is engine operating temperature. This allows the engine to get quick oil flow when it is started cold verses dry running until lubricant either warms up sufficiently or is finally forced through the engine oil system. The advantages of a low W viscosity number is obvious. The quicker the oil flows cold, the less dry running. Less dry running means much less engine wear.

[CADplans]

My info was not taken from any website, that is data I researched before Al Gore invented the internet!!

Multi weight oils can ACT like different weight oils at different temperatures, but how?

Heat up candle wax, what happens, it gets thinner!!

Heat up cooking oil, it gets thinner!

Cool off diesel oil, it will get thicker!

Just the opposite of what you want for engine protection.

Multi weight oil (example,5W-30) is a single weight oil with a temperature sensitive modifier that can increase base viscosity of 5W up to 30 as the temperature increases. Great for water cooled engines, for which it was developed.

But, the modifier can only modify up to a certain temperature.

Air cooled engines operate at higher temperatures than water cooled engines.

Above that temperature, the modifier fails to modify, the oil reverts back to 5W.

Exactly what you do not want!!

Think of the modifier as a long chain plastic molecule (which I think it is).

The plastic weakens above its functional temperature. The viscosity drops.

I ain't putting 5W, 10W, or 15W oil in any air cooled engine that will be used at normal load requirements.

Maybe, when and if I move back north, I will change my beliefs.

[jbollis]

Originally Posted by cubs-n-bxrs

Your whole theory is backwards. This was taken off of the Amsoil website.
OK . . .What does a 5W-30 do that an SAE 30 won't?
When you see a W on a viscosity rating it means that this oil viscosity has been tested at a Colder temperature. The numbers without the W are all tested at 210° F or 100° C which is considered an approximation of engine operating temperature. In other words, a SAE 30 motor oil is the same viscosity as a 10w-30 or 5W-30 at 210° (100° C). The difference is when the viscosity is tested at a much colder temperature. For example, a 5W-30 motor oil performs like a SAE 5 motor oil would perform at the cold temperature specified, but still has the SAE 30 viscosity at 210° F (100° C) which is engine operating temperature. This allows the engine to get quick oil flow when it is started cold verses dry running until lubricant either warms up sufficiently or is finally forced through the engine oil system. The advantages of a low W viscosity number is obvious. The quicker the oil flows cold, the less dry running. Less dry running means much less engine wear.

I have to agree with you on that.
Harley recommends there own 20w-50 for for there v-twins. I can guarantee anyone that the engine in my Harley runs way hotter then any of our tractors do. It is 95 ci, 10.9:1 compression, runs on pump gas, makes 117 hp / 121 lb-ft torque at the wheel, and has been doing it for 11 years now. My oil temps run anywhere between 210* and 250*. Have seen it as high as 265*.