Re: switching to synthetic oils

Mr.Nice. <mr.nice@*nospam*clara.co.uk> wrote:

> My 1984 110 has done around 230k miles (2.5 n/a diesel engine).
> When I first got it I put 15w40 mineral oil in it. at the last oil
> change I tried 20w50 mineral oil (API=SF/CC).

If you use synthetic at motor of this mileage you will ruin it
instantly. Synthetic resolves all kind of bound dirt which will you like
sandpaper through your engine. Although its pointless tu use thinner oil
because every type of engine needs just the oil-thickness for which its
built.

Raoul
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Raoul Donschachner wrote:
>Although its pointless tu use thinner oil
> because every type of engine needs just the oil-thickness for which its
> built.

Most of an engine, except at the brief periods when it starts operate so
far above normal air temperature that they barely vary with weather
conditions. Peak oil film temperatures in the big-end bearings are >>
150 deg C, and similarly in the piston rings and tappets, film
temperatures are very high.

The 20W- part of the J300 specification refers to the maximum viscosity
of the oil at -15 deg C, and guarantees that the engine will crank fast
enough to fire. A 0W will crank at -35C, at 5W at -30C, a 10W at -25C etc.

The second figure of the oil (50, 40, 30...)is derived from a Kinematic
viscosity measured at 100C and a dynamic viscosity measured at 150C and
the J300 spec sets a *minimum* viscosity that must be exceeded to ensure
sufficient lubricant film thickness to protect the moving parts of
engine. AFAIK a lower viscosity improves fuel economy and the higher
viscosity improves engine life. The trick is to get the right trade off
between cranking, fuel economy and engine protection and that is where
the additive package comes in to play.

The chemical additive packages in fully formulated multigrade lubricants
are what allow good oils to be thin enough to crank and thick enough to
lubricate and not to degrade too quickly and as with everything life you
get what you pay for.

Steve & Lizzy

"Raoul Donschachner" <[email protected]> wrote in message
news:1gmwmtz.3376g018s3kifN%[email protected]...
> Mr.Nice. <mr.nice@*nospam*clara.co.uk> wrote:
>
> > My 1984 110 has done around 230k miles (2.5 n/a diesel engine).
> > When I first got it I put 15w40 mineral oil in it. at the last oil
> > change I tried 20w50 mineral oil (API=SF/CC).
>
> If you use synthetic at motor of this mileage you will ruin it
> instantly. Synthetic resolves all kind of bound dirt which will you like
> sandpaper through your engine. Although its pointless tu use thinner oil
> because every type of engine needs just the oil-thickness for which its
> built.
>
> Raoul
> --
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> ==To e-mail me exchange das_liest_keiner with anything else==
> ****This space to rent****Hier könnte Ihre Werbung stehen****

Why do people always assume that syntheitic oil is thin?? Why not reap the
benefits of a synthetic oil and still use one that is the specified grade??
Use a 15w40 or a whatever grade of synthetic oil - and don't do the usual
cheapskate trick of leaving it in the engine longer 'cause you can. Change
it at the same intercal as you would a mineral oil but be better pritceted
whilst it is in there!

David
LLAMA 4x4
www.llama4x4.co.uk

Steve Taylor <[email protected]> wrote:

> The chemical additive packages in fully formulated multigrade lubricants
> are what allow good oils to be thin enough to crank and thick enough to
> lubricate and not to degrade too quickly and as with everything life you
> get what you pay for.

As far as my knowledge and experience goes, you don´t do any good to
older engines with thin oil. My Mini for instance runs abnormal hot and
looses oil-pressure in hotter days if run on 15W-40 instead of 20W-50
what is recommended. And the Mini has just covererd 25k so the engine is
not worn at all.
I wouldn´t mess with thinner oils hoping for better fuel economy which
would be in the 1-2%area if any.

Raoul
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David_LLAMA4x4 <[email protected]> wrote:

> Why do people always assume that syntheitic oil is thin??

I don´t do it, the original poster asked about him using thinner oil,
regardless of mineral and synthetic.
As I stated before, if you use synthetic on an engine with that mileage,
you just ruin it because of the resolved dirt. Thats a fact because it
is one of the merits of synthetic oil.

Raoul
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> I don´t do it, the original poster asked about him using thinner oil,
> regardless of mineral and synthetic.
> As I stated before, if you use synthetic on an engine with that mileage,
> you just ruin it because of the resolved dirt. Thats a fact because it
> is one of the merits of synthetic oil.

A friend who owns and runs a garage says' that he's seen more damaged
engines over the years caused by oil problems than anything else. His advice
was simply to put in oil of the manufactures recommended type for your
engine and change it frequently, even sooner than the recommended intervals.

bw
Gail

Gail Stevens <[email protected]> wrote:

> engines over the years caused by oil problems than anything else. His advice
> was simply to put in oil of the manufactures recommended type for your
> engine and change it frequently, even sooner than the recommended intervals.

Thats what usually the experiences are.

Raoul
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In article <[email protected]>,
Mr.Nice. <mr.nice@*nospam*clara.co.uk> wrote:

> On Mon, 8 Nov 2004 07:43:32 -0000, "David_LLAMA4x4"
> <[email protected]> wrote:

> > Why do people always assume that syntheitic oil is thin?? Why not reap the
> >benefits of a synthetic oil and still use one that is the specified grade??
> > Use a 15w40 or a whatever grade of synthetic oil - and don't do the usual
> >cheapskate trick of leaving it in the engine longer 'cause you can. Change
> >it at the same intercal as you would a mineral oil but be better pritceted
> >whilst it is in there!
> >
> >David
> >LLAMA 4x4
> > www.llama4x4.co.uk

I was told that synthetic oil suffers from capillary creep, but mineral
oil doesn't. That means that even if it's the same thickness, you're
more likely to find the synthetic making its own way out of your engine
than you are with mineral oil.

But I don't know if this is true.

David

Mr.Nice. <mr.nice@*nospam*clara.co.uk> wrote:

> and if it does and I do a first oil-change at say 3k will I then have
> a cleaner better engine?

Not, this won´t work. If you do a complete overhaul, then you can use
it, in the already clean engine, but without sense except more expenses
for oil.

Raoul
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"Mr.Nice." <mr.nice@*nospam*clara.co.uk> wrote in message
news:[email protected]...
> On Mon, 8 Nov 2004 07:43:32 -0000, "David_LLAMA4x4"
> <[email protected]> wrote:
>
>>
>>"Raoul Donschachner" <[email protected]> wrote in message
>>news:1gmwmtz.3376g018s3kifN%[email protected]...
>>> Mr.Nice. <mr.nice@*nospam*clara.co.uk> wrote:
>>>
>>> > My 1984 110 has done around 230k miles (2.5 n/a diesel engine).
>>> > When I first got it I put 15w40 mineral oil in it. at the last oil
>>> > change I tried 20w50 mineral oil (API=SF/CC).
>>>
>>> If you use synthetic at motor of this mileage you will ruin it
>>> instantly. Synthetic resolves all kind of bound dirt which will you like
>>> sandpaper through your engine. Although its pointless tu use thinner oil
>>> because every type of engine needs just the oil-thickness for which its
>>> built.
>>>
>>> Raoul
>>> --
>>> .sig-Simulator 0.07ß
>>> ==To e-mail me exchange das_liest_keiner with anything else==
>>> ****This space to rent****Hier könnte Ihre Werbung stehen****
>>
>> Why do people always assume that syntheitic oil is thin?? Why not reap
>> the
>>benefits of a synthetic oil and still use one that is the specified
>>grade??
>> Use a 15w40 or a whatever grade of synthetic oil - and don't do the
>> usual
>>cheapskate trick of leaving it in the engine longer 'cause you can. Change
>>it at the same intercal as you would a mineral oil but be better pritceted
>>whilst it is in there!
>>
>>David
>>LLAMA 4x4
>> www.llama4x4.co.uk
>
> will a synthetic oil (say 15w40) clean gunk from inside the engine as
> Raoul says?
> and if it does and I do a first oil-change at say 3k will I then have
> a cleaner better engine?

This engine will never be clean. As soon as you change the oil it will be
pitch black. What you need is an oil that cleans this **** by holding it in
suspension and not allowing it to settle as deposits. If you use an
appropriate oil then although the oil will be dirty, the engine surfaces
will not have any deposits looking like treacle or soft dirt as this stuff
will be flushed out with every oil change. Also do not be seduced by people
who claim that early oil changes will benefit your engine in any way.
*Appropriate* oil changes with appropriate oil is what it needs. Remember
also that unless your engine has been overhauled, with the best will in the
World, it will not last indeffinately without repair and overhaul.


>
> Although I'm now tempted to stick with the 10w50 mineral oil.
>
>

You will need a minor miracle to find a mineral 10w/50, let alone a high
detergent one. A high detergent oil is absolutely essential for your engine.
Please learn to distinguish between viscosity and performance requirements.

Huw