oil viscosity and clearance study

[pbonsalb]

Is 10W60 really ideal for factory bearing clearance? This article discusses some of the issues:

http://www.substech.com/dokuwiki/dok...ngine_bearings

[SVH]

Originally Posted by pbonsalb

Is 10W60 really ideal for factory bearing clearance? This article discusses some of the issues:

http://www.substech.com/dokuwiki/dok...ngine_bearings

Interesting. Seems 10W60 is better for the bearings with extra clearance. For factory clearance? Don't know.

[kawasaki00]

There are so many variables that can change every single conclusion that article says.

[M3anest]

You'll notice a lot of members on this forum have switched to 0W40 and are pretty content with the switch. I personally don't agree that 10W60 is the best oil for the car, which others swear by, in terms of longevity. It's all preference to be honest.

[Solo_M_Tech]

We've graduated from beating a dead horse, to full on lynching it now...

[Siajoon]

Originally Posted by Solo_M_Tech

We've graduated from beating a dead horse, to full on lynching it now...

Hahahahahah hahahahahah a I just laughed so loud at work and everyone just looked at me confused....

[amrazM]

Not another oil thread.

It’s simple 10w60 isn’t good at low ambient temperature start ups where the oil pressure takes a second or two to build and flow into the crankshaft bearings but at operating temperature pushing the car hard around a track you will see 240-250*F at that point you get an idea of the reasoning of running such a high viscosity.

[Siajoon]

And just because I want to lynch a bit, whoever thinks they can put 0 Weight oil in our cars have lost there damn mind.

Heat breaks down oil and reduces its weight a bit, so imagine putting in 0 weight and having the heat break it down even more... imagine splashing your hand in a pool, that's what it looks like in the s65 with that low of a weight.

[pbonsalb]

0W40 is 0 when hot? I thought it was the other way around.

[Siajoon]

Originally Posted by pbonsalb

0W40 is 0 when hot? I thought it was the other way around.

Apologies, yes you are correct the first number signifies how well the oil does in colder weather, lower first number better for colder weather.

Nonetheless, putting a lower weight then recommended is just breaking it down further and reducing its weight even more

[tlow98]

Originally Posted by Siajoon

Apologies, yes you are correct the first number signifies how well the oil does in colder weather, lower first number better for colder weather.

Nonetheless, putting a lower weight then recommended is just breaking it down further and reducing its weight even more

I think you need to go do some reading and learning about viscosities. There’s a lot to it - viscosity is just scratching the surface of the important parameters. It’s a field of study with deep roots.

[pbonsalb]

I have been running 0W40 or 5W40 in my 08M3 since 2014, when I changed to wpc treated stock bearings which give about the same as stock clearance. Only have 35k on the replaced bearings. Thought about changing them again to have a look but it’s a big project and expensive and I have been busy so I will wait until I am looking for a project. My originals had 60k and did not look as bad as many I see posted, so I figure the replacements will last at least 60k.

[Ximian]

I imported some 0W-8 oil from Japan and it's been working fine. For track days, I add 2 liters of 0W-16 to get a good mix.

[BIGMIG]

YEHAW oil thread.

With BE bearings I am running 10w60 in -30f to -50f and with no additional wear because of the added clearance. A an oil pan heater helps a bunch.

Surprisingly it doesn't take too long to to get up to temp. But then doesn't oil cross 185f too often

I drive my car too hard to not have a W60 oil of some kind year round. And Pennzoil Racing has the best viscosity index for high and low temps.

[BimmerMan33]

Originally Posted by MiguelY

YEHAW oil thread.

With BE bearings I am running 10w60 in -30f to -50f and with no additional wear because of the added clearance. A an oil pan heater helps a bunch.

Surprisingly it doesn't take too long to to get up to temp. But then doesn't oil cross 185f too often

I drive my car too hard to not have a W60 oil of some kind year round. And Pennzoil Racing has the best viscosity index for high and low temps.

Maybe the 10W60 in winter is ok since you have increased clearance with BE bearings BUT the main bearings clearance is still tighter than industry standard. I therefore prefer to use 5W50 or maybe 5W40 if extreme winters.
Yes the 60 viscosity protects the engine when oil is warmed up and driving hard! But with a lighter oil, you could just monitor the oil temps more closely and back off if getting too hot. Oil shears (loses some viscosity) when too hot, you could modulate your driving behavior and avoid running oil temps on the higher side.
Of course, in summer/frequent track use, 60 oil would offer the most protection.
I am still concerned about cold start wear with 60 oil even in non winter weather since main bearing clearance is tighter than industry standard!!

Comments... on how to preserve main bearings??