What is the difference between these types of oils?

Question

My owners manual recommends SAE 10W30 type SH for my Yamaha 125cc, I would like to find out if I can use say 10W40 or 5W40 or 15W50 ect in my bike?

And also what does the type SH stand for?

Thanks for your help

Answer 1

Ok boys and girls....first off, oil thins out (looses viscosity) as it get hotter. More on that later. There are straight weight oils, 10, 20, 30, 40, 50 and multi viscosity oils, 10W30 15W50, etc. A straight weight oil is going to be stiff and thich when cold and thinner when hot. A 50 weight oil is going to have a higher viscosity (be thicker) when cold than will a 10 weight, regardless of the oil temperature.

In the good old days when there was nothing but straight weight oils, in zero temps a 50 weight was so stiff the starter couldn't turn the engine over but in 100 degree heat, a 10 weight was thin as water and wouldn't not properly lubricate bearings.

Along came multi-vicsosity oils. A 10W40 was as thin as a 10 weight when cold but as thick as a 40 weight when hot. I think this is where the fellow came up with the idea that oil thickens as it gets hot...well not exactly but close. Multi weight maintain their viscosity as temps increase.

The SH is a gasoline oil rating while diesel oils have a rating starting with C. If you look on the back of the oil jug, you'll see some oils are S only while others have both a S and a C rating and are adequate for either type of engine. The latest oils (SJ I think, too many to remember) are different from earlier ratings since the latest oils have very little zinc in the formulation, which isn't good for old engines with flat tappets as opposed to roller tappets. The zinc provides a strong barrier under high shrear loads...like tappets sliding across the cam lobe.

Normally the only oils you can find are the ones with the latest rating or something like a SA, the really cheap crap you find at discount stores for a buck a quart. DON'T use that stuff except maybe for your lawnmower.

A long time ago (for you guys, 1985) when Chrysler came out with their turbo engines, those engines had a higher oil rating requirement than the non-turboed jobs (SG for turboed vs SF for others I think??). This was necessary because the oil had a very hostile environment to work in when lubricating the super hot, ultra high speed turbo bearings.

You may have a hard time finding a SH oil anymore. I've switched to diesel oils since most of them still have the higher zinc levels (except for the very latest rating, can't remember it's number off hand). I'm using the conventional-synthetic mixes and like them. If you can find a farm store nearby, you shouldn't have any problem at finding an assortment of diesel oils, especially the preferred older rated oils.

Answer 2

Just a correction on Elliot J's comment thast oil weights (viscosity) ratings vary between 10 and 90 they go as low as 5 and my truck uses 75W140 in the rear axle.

The higher the viscosity rating the thicker the oil is and vice versa.

You should use the oil specced by the manufacturer. When the bike gets older you might want to use an oil with a little bit higher viscosity to avoid high oil consumption.

Answer 3

SH is just a classification, a fairly old one now, this has been superceeded by better more modern grades i.e. SJ,SL and more recently SM. Use the grade the manufacturer recommends, they have tried and tested your engine in all conditions.
So 'Me' thinks hot oil gets thicker? Why warm up your engine to help the 'thicker' oil drain on oil change then?

Answer 4

SAE 10W30 is what is recommended so thats what should used.
Believe it or not oil works back to front,Oil gets thick with heat,Yep thats right gets thicker.
30 is the thickness ( vesocity) To thick can do a lot of damage to thin can burn off very quickly.
10 is cold this help the engine to move freely on a cold start,to thick at start up can also do damage due to lack of oil flow.
The W is the oil weight.
They give you oil type to help you and you bike.
Colder countries run different oils and this also goes for hotter
countries.If you in average temps them put the recommended standard in.

Answer 5

Here is a simple way:
All Japanese Bikes use 10W40
All European and American Bikes use a 15W40

Answer 6

Oil weights go from 10 to 90. 10 is the lowest viscosity (lightest) used for warm weather. 90 is axel greese. A SAE 10W40 give you a broad range for most American climates for cold to hot weather. I live in Houston and don't need the higher weights. I use a 10W20.

Consider the types of temperatures you will be riding in. Select oil weights based on that.

Type SH! You've got me!