mobile1 0w 40 e30 318is

[DesktopDave]

I need to run a pressure gauge at operating temp and collect some good data.  We can talk this to death without any result unless solid, objective, repeatable data is posted & analyzed.  On top of that, every motor is different.  Even M42s will vary from car to car.  My 278k mile motor, sitting outside in freezing rain will be quite a bit looser than some low-mileage garage queen!

Despite that, all the motor oils I've tried were very good.  A few are excellent.  Filters are another matter entirely.

I've also been over at BITOG checking out the details, but there's so much detail it's overwhelming.  I do have a life outside of a car...so I'm not going all obsessive about motor oil.

So until I get some hard proof, I'm sticking with the thinner synthetics.  The car just sounds better, and the motor is spotless inside.  Good enough for me so far.  I picked up a sample kit from Blackstone to see what my minivan is doing internally, I'll share results if I get to the M42.

I'm planning on using RLI veggie oil next, as soon as I run out of my current synthetic stocks.  Saving the planet, one oil change at a time...

[Ryann]

We can talk this to death without any result unless solid, objective, repeatable data is posted & analyzed.

I totally concur. So until said data materializes, I'm going to stick with BMW's recommendations!

[VegasKyle]

I wasn't referring to oil viscosity at startup, and in fact didn't mention at all. You did.

BMW is one of the most renowned engine designers/manufacturers in the world. I simply suggested following BMW's recommendations for oil selection, rather than making an uneducated judgement (AT LEAST from a mechanical standpoint) that the oil the engine manufacturer specified is "too thick".

You said thicker oil was better for the lifters and tensioner.  I was just wondering how an oil that takes longer to get to the lifters is better.  The majority of engine wear occurs at startup so I want an oil that is going to get to all the parts quickly.

Like Dave said you need a pressure and temp gauge to be sure.  Lucky I found someone who did just that.  The sump temps were quite low.

Oil pressure is another place where people have misconceptions.  Most people think more is better.  Pressure is the measure of resistance to flow.  You want your oil to flow.  The point of having oil in your engine is to #1 cool and #2 lubricate.  10psi per 1000rpm is a good rule of thumb.  I've also seen 75psi @6000rpm used.

Also, Im not making an "uneducated judgment".  There is a member of this forum who uses Shell Rotela 5w-40 thats speced for diesel engines and he's a petro chemist.  Just because someone isn't using the 15w-50 or 20w-50 dino oil that the owners manuel calls for doesn't mean they don't know what they are talking about.

Bottom line. Is 20w-50 going to hurt the engine? NO. Is it the best oil for the engine? No.

[Ryann]

Listen, if you're worried about engine wear at startup use synthetic oil. It clings to engine internals better and longer than mineral based oils regardless of viscosity.

The reason I'm guessing BMW's suggestion for higher viscosity oils for the m42 has to do with it's hydraulic components is because as an experienced engine builder I know that the clearance specs for journals/bearings, pins, valve guides, etc. are all very similar to any other engine out there. I also know that hydraulic components are one of the few things that have been re-engineered in recent years to function properly using lower viscosity oils.

Bottom line: the best oil for the engine is the oil specified by the engine designer, not a petro chemist or a driveway engineer.

[VegasKyle]

Bottom line: the best oil for the engine is the oil specified by the engine designer, not a petro chemist or a driveway engineer.

On a new car I would tend to agree with this.

The engine designer recommended the best oil (who knows what compromises were made) available at the time.  Thats the key.

The oils that were available 20+ years ago when the M42 was developed no longer exist.  Every oil that is on the market now is different, they meet entirely different industry standards.  There were additives common in oil then that are completely omitted from todays oil.  The base stock used in many of todays oil and many of the additives didn't exist.  They are also better quality.  From cheap Penzoil Yellow Bottle to the most expensive synthetic, they are all better than what was on the market when the M42 was designed.

What you are suggesting is the equivalent of finding a piece of software from 20 years ago then looking for a 386 to run it.  Just because something was once the best option doesn't mean it will always be the best option.  It's like the analogy I gave about the Stanley Steamer.  I doubt anyone would say that the oil the engine designer recommended is still the best option.  

The 80's were a long time ago.  Technology has come a long way.  Engine oils are no exception.

[Ryann]

I wonder what BMW's engine guys would have to say about this.

[bmwm42]

Lmfao

[DesktopDave]

I suspect everyone is correct on this one.  Oil threads never get to a solution, there are too many variables and preferences.  Factory spec dino oil is more than adequate for our engines.  Thinner synthetics will absolutely free up some power and fuel economy.  Extending the effective life of your engine is the kicker though...there are many ways to skin that particular cat.

I'd highly recommend going over to BITOG.  They have hundreds if not thousands of members testing every conceivable aspect of lubricants.  They have chemical engineers, powertrain designers, shadetree mechanics and obsessive car guys all trying to get the most out of their oil.  Took me a while to figure bits of it out - and I still have trouble with their acronyms...EDI (extended drain interval) is the one I've been focusing on myself.

[Ernest]

nm

[romkasponka]

IMHO it is impossible to make oil viscosity same at 0 deg C and at 90deg C (normal engine operating temperature). So there is compromises made as mentioned before. Engineers specified viscosity for normal engine temperature and with this temperature engine works longer than with 0. So 0W30 oil is better than just W30, because oil viscosity at low temperature is closer to specified at 90deg C and engine have better lubrication.

I agree that there is no point to use 0W30 oil there outside temperature is 20deg C or more.

I prefer 10W60 for summer time(~25deg C) for my project car and 0w40 for my daily 318is m44 (Sumer/winter -30/+30deg C).

[Balkanac]

i've been running Penrite (aussie made) semi-syntetic 0w40 for a year now and the engine loves it. I live in Perth, australia and it get over 35 degC regularily here for about 6 moths. the car has been loving this oil, but i do change it every 5-6000km (3-4k miles) and my engine has done 180k kms (almost 120k miles)
This oil has been highly recommendd for the zinc content it has, but whenever i drain it, it comes out properly black. not sure why

[Quent]

Hi there.  I'ma 31i8 Is (E36) owner  as well as  of a 2002ti (1969).

I wanted to ask you guys  if  anyone  ever  used  a 10w60 synthetic racing oil such as Selenia Racing in an M42/M44.

I have used this on my Fiat Uno Turbo and  on my Alfa 33 1.7  with very very good results  but am somehow cautious about putting it in my 318is, especially after reading the thread above.

Any opinions & suggestions are welcome.

Regards

Quentin

[DesktopDave]

Opinions on oil are very strongly held, most times.  I'd say that any synthetic is a pretty good idea.  OTOH, conventional oil is nearly as effective.  I'd say go for it, let us know how it works out.

I'd also strongly recommend the forums over at BITOG...there is more good information there that I could digest in a year.