DivinDriver

iTrader: (15)

How do I cancel my membership here!?!?!

TOFUDRIFTER

Ok, epic noob moment. But what do the numbers mean when referring to oil? Like for 5w30 what do the numbers mean? Haha xD. Maybe if I knew that I can make a more educated decision.. but I'm gonna up my weight for sure.

xXGslseSleeperXx

viscosity in cold temp(W=winter)and viscosity at operating temp. numbers are set by a scale determined by SAE

TOFUDRIFTER

Wow thank you. In all my life I never understood that... Haha.

Qingdao

iTrader: (3)

First number is cold weight then the second is warm.

5W30 has a cold weight of 5 and once the engine is at operating temp it is 30 weight.

Its so that on start up engines have a chance to move the oil around, but when the engine warms up the thicker oil will kick in and lubricate proper.

Just to clarify... there aren't TWO oils in a mixture, but I supose it would be simple to think of it in that way.

TOFUDRIFTER

Yeah I didn't think there were 2 but still thanks for clarifying! I did an oil change today, I used Lucas brand oil 10w40. I'm not too comfortable atm going any higher. But I'm a huge Lucas brand nut, products of that brand have kept some cars that shouldnt be running alive. So I figured ill give it a shot!

Thanks for the help everyone!

ClineStine

I live in southern cali vally and it gets hot here, so ive always used 20w50 ive also wondered if its too think for the omp but really dont see it being an issue, i would suggest using something thicker than the 5-something you said you used, im sure you know rotaries like to get hot.

Kentetsu

I ran Castrol 20/50 for years without issue. For the last couple of years though, I've been using Lucas, for the same reasons stated above. Everything they make works exactly as advertised. That's pretty rare...

DivinDriver

iTrader: (15)

I have, and still do.

j9fd3s

iTrader: (3)

Peepers gets Castrol HD40, race car gets straight weight oil. long story short, dad did some research and found this http://www.castrol.com/castrol/subse...tentId=7027417 and out of the oils they have the HD40 looks quite good, and is actually easy to find.

the vert is just a street cruiser, it gets whatever is on sale...

diabolical1

iTrader: (3)

this is where i stand on any street-oriented car.

i'm tempted to agree with you. there is a different breed of fool over there, for sure.

REBELDE

iTrader: (4)

Castrol GTX 20w 50 12a, 13b, turbo, bridged, holley or fuel injected............till the day I die

xXGslseSleeperXx

Same here, always GTX except when i use idemitsu, but i usually gotta skip lunch that day

peejay

There's a lot of misconceptions in this post.

First and foremost, viscosity has nothing to do with the oil's lubricating properties.

The multi-viscosity rating is based on the oil's temperature. That is to say, a 5W30 oil is the same viscosity as 5 straight-weight when both are at 0 degrees (C or F, i forget which) and the same viscosity as 30 straight-weight when both are at something like 180F.

Notice that the viscosity is being compared to oils at the same temperature. Multi-viscosity oils never get thicker with heat, they just lose viscosity less quickly.

For extreme example, the 0W60 synthetics used in some BMWs are very, very close to not losing any viscosity at all with temperature, at least within the range of the test.

j9fd3s

iTrader: (3)

here's the SAE viscosity chart for engine oil, there is a different one for the transmission oils