Spoken as a true Tribiologist !

Oil pressure relief valve is supposed to bleed off excess oil pressure
cold of course. ( or any time it's too high )

On 5/14/2012 9:08 PM, Stuart MacMillan wrote:
> I agree.  BTW, the study of lubrication is called tribology.  Factoid of the
> day.
>
> The thing about multi viscosity oils is that it's chemical "viscosity
> extenders" that give an effective viscosity range.  The oil "behaves and
> lubricates" like a 10w at low temps, and like a 50w at high temps.
> Unfortunately, the physical viscosity (the thickness of the oil) is very
> thin to give a 5w or 10w cold temp rating.  That can be a problem in our low
> pressure engines, particularly in warm weather.   I ran 20w 50 Red Line
> synthetic oil for years, but it was a bit thick in winter.  I broke a cast
> aluminum oil filter housing when it was about 20 degrees starting up one
> morning, (new 2.1 engine) and I've heard of stock oil coolers blowing up too
> in cold weather.
>
> Maybe run a 10w 50 in winter and a 20w 50 in summer?  The mandate to get
> better gas mileage has led to thinner oils that are easier to pump around,
> thus using less engine power, and that's not what we need in our old loose
> engines.
>
> Stuart
> '85 Westy
>
> -----Original Message-----
> From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
> Scott Daniel - Turbovans
> Sent: Sunday, May 13, 2012 7:56 PM
> To: vanagon@GERRY.VANAGON.COM
> Subject: Re: Castrol Hypuron 15W-40 Synthetic Blend?
>
> hi..
> oil can be studied 'forever' .
> I would say though ..
> that generally .. a wide viscosity ratio is 'less good' .
>
> You will notice there are not many very wide viscosity range oils.
> like 10W50 is seldom seen.
>
> Of course , anything that anyone says about engine oils can be challenged or
> debated by others ..almost always.
>
> what I personally think..
> on our usually very used engines ..the higher number is the more important
> one.
> In summer on most vanagons engines that should be 50 in my world.
> I think the oil pressure on a hot engine is very important ..
> and the '50' is what helps there.
> I do not find or think, myself, that on old engines ...it has to have a low
> lower number .
> I am happy with 20W50 in used vanagon engines in summer..
> and find that oil pressure is always somewhere between 6 and 60 ..
> in other words..
> 60 at  high  rpm cold at say 2,500 rpm ..
> and  6 at a hot idle.
>
> on the other hand ..and I'm still 'thinking about this' ...
> I know a VW parts store where the owner swears up and down that TDI engines
> must have a 5W30 in them..or a 10W40 ..
> and that using 15W40 causes the hydraulic lifter tops or cam lobes to fail.
>    I don't know if that's actually true.
> All newer engines generally call for thinner oils ..partially for fuel
> mileage reasons I suspect.
>
> one oil I like is Joe Gibbs high zinc formulation 15W50 .
> For old fashioned flat tappet engines ..
> which all our VW engines are ...
> they would be happier with oils with more zinc additives in the oil ..
> very modern oils are formulated with less of that addtive to protect
> catalytic converters.
>
> about friction at start up ..
> oil really sticks to metal surfaces.
> if you ever try to drain off every drop of oil from something like an oil
> pan..
> oil will be coming off the inside surfaces for a long, long time. Days and
> days.
> So on engines with say 150K miles on them....I don't think the really need
> a really thin oil unless it's extremely cold.
>
> I am big on additives to help tired engines ..
> such as Lucas Oil Stabilzer .
>
> the BMW 10W60 ..
> expensive I bet and I am not convinced it is really right for our old
> fashioned engines.
>
> one member says he as always run Mobil 1  15W50 I think...and has 200K miles
> and still going strong ..
> I respect and appreciate that.  A good product I am sure.
>
> something that made a big impression on me ..
> an article, years ago, about how a new engine makes so much more friction
> than an old used one..
> and therefore it was imperative to always replace the radiator with a new
> rebuilt engine.
>
> what I glean from that is that old tired engines don't have a much friction
> ..
> and there is less to worry about ....just that mainly the oil is thick
> enough ..
> that it's changed regularly ...
> and my 3 rules for caring for any VW engine going back over 40 years..
> 1. keep it in perfect tune.
> 2. keep good clean oil in it.
> 3. drive it nice.
>
> the real right way to determine oil performance and health of an engine is
> by oil analysis.
> even regular ones, like every say 25K miles.
> then you need two identical vans ..
> of the exact same age and miles..
> one type of oil in one, another in the other ..and compare long term oil
> analysis results.
>
> I think how it's driven is the main factor.
> I have one very good 1.9 waterboxer engine with a piston slap in it..
> I am pretty sure the owner of that engine reved it hard , immediately, each
> time he fired it up.
> We want to start our engines as gently as possible of course..
> that is their worst mode...starting  and the first few seconds, followed by
> the first few minutes .
> And don't let them sit idling cold to 'warm up'  - that is really rough on
> engines.
> Start gently, drive gently first few minutes ..under light load so it can
> warm up.
> You can read this in a 1958 Mercedes 220S owner's manual even.
>
> scott
>
>
>
> On 5/13/2012 6:22 PM, neil n wrote:
>> Thanks people.
>>
>> Ironically, given the jokes some of us make about oil discussions, I
>> know very little about engine oil. But it's something I need to learn
>> more about now.
>>
>> Maybe an oil with a wider range of viscosity would be best. I don't know.
>>
>> Google is my friend!
>>
>>
>> Neil.
>>
>> On Sun, May 13, 2012 at 5:00 PM, John Meeks<vanagon@gmail.com>   wrote:
>>
>>> Interesting stuff. Sounds like 'soot' is kept in suspension better
>>> than coventional oils designed for gas engines. The shear numbers
>>> look good. Resistance to shear might make up for the 40 weight. Don't
>>> know what other factors are in play in the gas vs diesel comparison.
>>> Anyone?
>>>
>>> 15w50 Mobil1 is really hard to find this year for me. NLA?  Some
>>> 10w40 is still on the shelves which is what I ran last winter.
>>> Looking around for alternatives.
>>>
>>> John Meeks
>>> '91 Vanagon MV Phoenix
>>> Northern Michigan
>>>
>>> Vanagon Rescue Squad
>>> www.vanagonauts.
>>>
>>>
>>> On Sun, May 13, 2012 at 3:49 PM, neil n<musomuso@gmail.com>   wrote:
>>>> Hi all.
>>>>
>>>> Searched  "Hypuron" in archives. Didn't get any hits.
>>>>
>>>> I don't know if the TBN and Low Ash aspects help a gas engine, but
>>>> looking at "Oxidation Control&   Shear Stability" here:
>>>>
>>>> http://www.castrol.com/castrol/genericarticle.do?categoryId=82915547
>>>> &contentId=7025207
>>