Date: Thu, 30 May 2013 07:23:56 -0700
Reply-To: Don Hanson <dhanson928@GMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Don Hanson <dhanson928@GMAIL.COM>
Subject: Re: oils and gasoline Oil Viscosity at temparature.
In-Reply-To: <BAY152-DS254EF5FBE33F552461A21A0910@phx.gbl>
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I concur on the oil temperature gauge being most informative. The
coolant gauge tells you about the coolant but the oil temp is a more
accurate 'read' on how hot your motor is running, how much 'heat-sink' it
has.
My inline VW Jetta motor usually runs at around 205f at highway speeds of
60-70mph. When I first swapped to the 2.0 liter block, I ran for a short
time without the VW oil/coolant heat exchanger adjacent to the oil filter
housing and I was seeing high-load temps of 230f (Autometer brand
gauge)...This caused me alarm so I plumbed in the usual VW heat exchanger
filter housing, to keep the engine internal (as indicated by my oil
temperature) temps lower. I keep a close watch on my oil temp and am
contemplating a second aux oil cooler with a thermostat, for those few
times I run the van fully loaded up long grades into headwinds, at speed.
My oil temp will climb after about 2 miles of 5% + grade,
On Wed, May 29, 2013 at 9:40 PM, Dennis Haynes <d23haynes57@hotmail.com>wrote:
> When reading SAE oil grades for multi-weight oils the lower or "w" number
> refers to the oil at 40C and upper number is at 100C. A common viscosity
> measurement is centistokes, (cSt). SAE 50 will have a viscosity near 18 cSt
> at 100C regardless of whether it is a synthetic or not. The Mobil 1 15w-50
> will have a viscosity of 125 cSt at 40C. A 20w-50 will be closer to 170 cSt
> at 40C. The synthetics usually have a wider viscosity index without as much
> need for modifiers and their performance can shine at temperatures far away
> from these standards.
>
> One thing that needs to be understood is that for loose tolerance engines
> or
> those that are worn too much clearance on one side always means less or
> insufficient clearance on the other side. As such loose engines can
> actually
> be more demanding of the oil to keep the parts separated.
>
> As important as an oil pressure gauge is it is even more helpful the have
> an
> oil temperature gauge. The Water boxer has a wonderful (?) ability to have
> oil temperatures not follow the coolant temperature, especially at high
> speeds and loads and the situation gets worse when the crankcase is over
> filled. It is these high oil temps that cause the loss of oil pressure both
> from viscosity loss and the case expansion letting the bearings get loose
> and the pump to lose its ability to pump. The oil can go into thermal run
> away and this is where we get those thrown rods. If not for this phenomenon
> the Water boxer would have no problem running with a *w-30 or *w-40 oil.
> For
> daily winter driving (to-from work) I use the 0w-40 which works just fine
> on
> my red van which is completely stock. For summer and/or long trips I want
> the 15w-50.
>
> Keep in mind that higher viscosity oils have their draw backs. They provide
> poorer lubrication when cold and they rob power and economy.
>
> Dennis
>
>
> -----Original Message-----
> From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
> Stuart MacMillan
> Sent: Wednesday, May 29, 2013 12:26 PM
> To: vanagon@GERRY.VANAGON.COM
> Subject: Re: oils and gasoline
>
> Ahh, these threads are so much fun! Everyone has an opinion and an
> opportunity to join in. I can't resist.
>
> Regarding better mileage with premium gas, if it doesn't contain 10% (it
> does here in WA, you are fortunate in Canada) you will get about 3% better
> fuel economy due to the lower energy content of ethanol (ethanol adds
> oxygen
> for more complete combustion). Since you are getting more than that, then
> you probably have some carbon build up that is increasing compression to
> the
> point where you get some knock with heavy loads on regular.
>
> Regarding synthetic oils and viscosity, the SAE rating is "effective
> viscosity," not physical viscosity. A 15w-50 synthetic oil is physically
> thinner than a 15w-50 dino oil, but the chemistry of a synthetic (more long
> chain molecules of consistent length plus viscosity extenders) offers the
> same effective viscosity lubrication with higher breakdown temps in a
> thinner (purer) oil.
>
> With its being thinner we can run into low oil pressure issues with some
> synthetics in our loose WBX engines (the hotter they get the looser).
> 15w-50 should be fine, but 20w-50 may be needed in worn engines since it is
> physically thicker than the 15w-50. Run the 5w oils ("mileage boosting"
> oil for modern cars) and you can have pressure problems at high temps.
>
> Which brings me to my last point. All WBX engines should have an oil
> pressure guage! Van Café has a great kit at a great price (I did my
> research):
> http://www.van-cafe.com/home/van/page_362_263/oil_pressure_gauge_kit.html
> Best money and two hours you'll spend.
>
> I had one on my '84 and am installing this one on my '85 this weekend (and
> I'll transfer it to the Subaru engine). It didn't keep me from blowing up
> my engine, but at least I knew I was on borrowed time:
> http://volksweb.relitech.com/21rodbrg.htm
>
> For more fun reading on oil look up "tribology," which is the science of
> lubrication. You will learn that two of the best known lubricants are
> whale
> oil and castor oil (Castrol's original formula).
>
> Stuart
>
> -----Original Message-----
> From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
> James Eaton
> Sent: Wednesday, May 29, 2013 5:16 AM
> To: vanagon@GERRY.VANAGON.COM
> Subject: Re: oils and gasoline
>
> >
> > Date: Mon, 27 May 2013 12:57:38 -0500
> > From: Jim Felder <jim.felder@GMAIL.COM>
> > Subject: Re: Engine Oil Question
> >
> > I don't think it's better, I think it's very good and moderately
> > priced. I know from many thousands of miles of experience that without
> > the right oil (of which Castol 20W50 is one) and the right filter, you
> > stand a good chance of hearing your waterboxer's oil buzzer go off on
> > a hot day of freeway driving.
> >
> > It has been explained to me by people who are in the business of
> > selling oil and in the business of building engines that the
> > waterboxer does not have tolerances that would take advantage of the
> synthetics' advantages.
> > It's like putting high test in the gas tank; it won't hurt the car
> > but it won't help it either, and costs more.
> >
> > Jim
> >
> Hmmm,
>
> Even back in the '80s, when I had my Rabbit, we were advised that if you
> wanted your engine to last you should run synthetic oil, especially if you
> ran a lot under adverse or high load conditions. And that was back when
> synthetics were all thin, thin, like 0W20. Now that synthetics are the
> same
> weight as regular oils, only with wider range (e.g. 15W50 is the same
> thickness as 20W50, except in the cold, where it's thinner for better lube
> at start-up), all engines, even those needing heavier oil to cope with high
> temperatures, can find a synthetic to do the job.
>
> And I have a contrary observation to your line about premium octane
> gasoline; our '91, with 290k km, gets 2-3 mpg more on 91 octane than on 87
> octane on the highway. (The owner's manual recommends the use of 91 octane
> under hot, high load conditions, which described our camping trips in
> eastern Ontario last summer.) A colleague who teaches and researches gas
> engine maintenance and repair suggested that the improvement is likely due
> to the superior flame front propagation properties of 91 octane under
> higher
> loads, and to the lower alcohol content (apparently in Ontario premium does
> not have to have the 5-10% alcohol that regular does).
>
> James
> Ottawa, ON
> '91 Westfalia Weekender
> =
>
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