Oil viscosity 20w50 vs 50

[Theycallmecrash]

Ive been running mobile 1 20w50, in vegas i was low low low, so topped off with 50 weight racing oil (nothing else around) and it seemed to run smoother quieter quieter. So anyone have some insight on my due now oil change, 20w50 or straight 50?

 

[Alfatango1]

If you live in Vegas keep straight 50. The 20 is what the viscosity is when cold, when it heats up it's a 50. Now in few months there when it's butt cold in the winter mornings and nights multi vis would be a good thing for start up.

 

[snrusnak]

They are basically the same. The first number(20) is what temperature it will flow down to. 20w50 is a 50 weight oil that will flow down to 20 deg F. 10w50 is a 50 weight oil that will flow down to 10 deg F. The colder the climate the lower the first number should be. If you live in a cold area where it gets to 0 deg F and you use 20w50 oil you may risk oil starvation on cold start.

So, to sum it up, in your case it doesn't matter.

 

[Sirius815]

@snrusnak - It's like 4:30am so I might have read your reply wrong, however the first number (before the W) is the weight of the oil at 0 degrees Fahrenheit - not the temperature that the oil will flow down to. 5 weight oil has a pour point down to -40 degrees Fahrenheit, and 0 is down to -50 degrees!

Multiweight oils are designed as a lower viscosity for cold startup, that however act like much thicker oils when they are hot due to the interaction of the added polymers.

For instance, if you used straight 20W oil, it would flow (at lower temperatures) just like when you do your oil change - at higher temperatures (common tables are at 212 degrees) - a 20W oil has a kinematic rating of 4.2 - very thin. The multiweight oil 20W50 has a kinematic rating of 10.3 - over twice as thick.

The rest of your reply is good though - I wouldn't run 20W50 if you're going to be cold starting at 0 deg F.


@Theycallmecrash - as alfatango1 said - because it's still so hot, you'll be just fine with straight 50. Just be aware that once the mornings a bit cooler, you'll want to go back to multiweight oil - as pointed out.

Also - just for FYI - the pour point for straight 50 weight is still around -8 degrees F. However, for the oil pump to actually circulate the oil, a minimum temp of ~20 degrees above the pour point is required. I personally wouldn't run 50 weight at 12 degrees F though.

Sorry for the lengthy reply

 

[snrusnak]

^Maybe I'm wrong, that's what I was told or read or something....don't remember where I got that info. I guess I'll have to look into it a little further myself so I know for sure what I'm talking about. Thanks.

 

[Alfatango1]

Sirius is correct. The first number is not temp but viscosity or lets make it simply thickness for lack of better term. It flows like a 20 weight until it heats up to normal operating temperature then becomes a 50 weight. I once got 4 quarts of 0W50 Mobil 1 for like a buck a quart since no one in Phoenix would buy it. Pouring it into the crack case you could literally hear it run through the engine like water.

 

[NSEGE]

Preface: I'm not a petroleum engineer, but my primitive understanding is simliar to Sirius'. A multi-viscosity oil will flow (viscosity rating) like a straight weight oil of the same viscosity, but has the shear strength of the higher viscosity in its rating.

I run 0W40 in my autos here in the frozen north (Montana) year-round w/o issues....used for a 6 mile commute primarily. I use 20W50 Mobile 1 in the bikes (Buell CityX and Kawasaki KLR650)....when it gets cold enough for lower viscosity ratings, I put StaBil in the tanks and wait for spring.

 

[Alfatango1]

The lower the first number the faster it flows through your system, so in colder climates you want a low number so it gets to vital engine components as fast as possible. A multi vis oil simply changes to the higher number when hot.

 

[CrazyTexan]

Everything there is to know about oils

Good reading info if you get bored

 

[Theycallmecrash]

Mind blowing amount of info on oils, i primarily live is southern cali, and frequent las vegas on the bike. So based on all this ill stick with 20w50. Not only has my question been answered learned a lot. Buellers are god damn geniuses it seems

 

[Sirius815]

[up] Thanks for the graph CraxyTexan - Wish I'd have found that last night

 

[user_deleted]

Buellers are god damn geniuses it seems

don't lump myself or lesley into that mix.

you're right crash. some very talented and intelligent folks on this site. i wish there was a running count of how many bikes were kept running/repaired with keyboard trouble-shooting on here.

 

[neilrl79]

I'm not sure of it's true or not but I heard if you put 6oz of canola oil in it's like putting a turbo charger on your bike.

 

[jaimz]

I'm going to go ahead and suggest that you not put canola oil in any engine unless you're running a diesel that has been converted to run on "bio-diesel"

As I'm sure the previous comment was a joke. However it will be like putting a turbo on your bike... until the engine gets destroyed due to the shear lack of protection. The only reason it could possible make the engine feel more powerful is because canola oil has such little viscosity that your engine doesn't loose power by sloshing through thicker oil.

 

[neilrl79]

I would have explained it was a joke but that tends to make things less funny.

 

[user_deleted]

neil: my superior intelligence allowed me to "get it".

 

[neilrl79]

John: I knew you'd get it.

 

[XRorXB]

Everything there is to know about oils

Spent an hour reading everything. So I can't understand why in the world 20W-50 is the recommended oil viscosity by Buell. Based on the arguments presented, 0W-50/40/30 (based on pressure experiments) would be drastically better for startup protection. And, synthetics being even thinner at 75F. Anyone?

 

[jaimz]

I would have explained it was a joke but that tends to make things less funny.

Yeah I know, lol sorry. I've just seen some people doing some questionable things because of jokes. Lol some people don't know. Once on a forum I read about a guy who said the ticking from his engine was loud (on a ford zetec) then someone jokingly told him to pour some sugar in his engine through the spark plug tubes because "it will melt and make a smooth surface for the parts to glide on" well guess what, two days later the guys car wouldn't start anymore because he thought it was serious.

Lol just protecting those poor buells from noob owners!

 

[Theycallmecrash]

So heres what ive done, 1 qt 20w50 1 qt straight 50, 1/4qt 0w20, 1/4 conolla oil, 1/2qt water, poured a teaspoon of sugar in each spark plug hole impacted the plugs back in, and running diesel.... Results 750hp!!! When great minds come together!