Big End Bearings

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Nice one Craig
So "in theory" by upgrading to Amsoil 5W30 HDD series 3000 heavy duty diesel oil with Toyo filters - you could push out oil changes to every 10K - or more
Niall
 
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Craig,
Sorry if I've missed it but could you explain to me why you select
calcium level in preference to any other element present in engine
oils?
When I spoke to Millers about the oil I use they told me their oil
ihas 2900 ppm calcium but as a detergent calcium reacts with other
components therefore this figure is not representative of anything
specific. It is rather a combination calcium and several other
components, such as magnesium, zink, phosphorus or sulphur, that
makes an oil suitable or not for a specific application.
--
Rgds,
Roman (London, UK)
'92 HDJ80
On 8/10/06, Craig Vincent <[Email address removed]> wrote:
 
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Hi Roman,
By your comment in regards to what Milners had to say they don't know
what they are talking about.
I try to keep my reccomendations as simple as possible so people can
find good oils that suit their cruisers. I will elaborate further though.
High calcium in the oil (3000-4500+ppm) implies that the oil has a
calcium based detergent dispersant additive package. Calcium based
detergents are thermally stable to quite high temperatures as a side
benfit they have very strong bearing pacification properties (i.e. to
prevent sub surface fatigue failures).
Magnesium in the oil means a detergent additive package that is NOT
thermally stable. It is fine in what would be typically known as
'american' style engines (does not neccessarily mean made in usa but
relates to combustion chamber design and piston crown design). Some
european engines it will be OK in. Japanese diesel tend to purposely run
quite high oil temps, partly due to agressive piston cooling regimes, if
magnesium based detergents are used they will degrade thermally after a
very short period. In that case you have a diesel oil with no detergent
and dispersant additive package it has decomposed. So piston crown
deposits will build up. Magnesium offers little or NO bearing
pacification protection.
Zinc and Phosphorous are used to make the compound ZDDP
(dialkyldithiophophate) these are a family of self sacrificing boundary
lubricants. There are lots of different versions some work better than
other you get what you pay for.
As far as I know sulphur it not an additive (but it maybe buried in a
useful compound).
Silicon is usually seen as a contaminant i.e. dirt but sometimes it will
be seen if analsing new oil as it is used in the chemical makeup of anti
foam additives useful in engines with hydraulic tappets or unit
injectors. Ford powerstoke diesels are very susceptible to foaming
reated oil problems.
Viscosity and viscosity index: say 15w40, the 15w comes from a cold
crank simulator oil is tested at specific temps and at that the CCS
viscosity must be a figure or less if not it is teted at the next
highest temp. The 40 part relates to the viscosity being within a
certain band at 100 degrees C. Theviscosity index is a measure of the
rate of thinning with increasing temp. Naturally without additive doping
VI will be about 100 in mineral oil, synthetic base stocks can be
naturally 150 or even higher.
What this means is say you have a mineral undoped (no VI improvers in
it) 15W40 oil and operate it at 150 degrees C and a 5W30 oil that has a
synthetic basestock it can actually be more viscous at 150 degrees C
than the 15w40!
VI improvers are a compound that behaves like a spring when it is cold
(think of a fully compressed bic biro spring) it is a compact molecule
when it is heated (think of the spring now relaxed and much longer) it
expands and tangles up with all the other VI molecules which sounds
ideal. But in a high shear environment the molecules breakdown or get
cut up and don't work anymore. So you may start with say 15w40 (or more
likely something like 5W60) and after some abuse it has turned into
20W30 (or 15W40 from 5w60 say).
Spec sheets are useful but they often do not give enough information and
if you ask for it you will often run into a brick wall of 'that
information is commercially sensitive' which is a cop out as you can get
it easy enough in under 2 weeks with a few dollars and lab testing.
If looking at them apart from viscosity (that must be within a certain
band any way to be that grade) and pour point which helps to give an
idea of cold weather performance. The following are helpful but not
often listed
VI will be listed but you don't know whether it was achieved with a high
VI base stock (good, because of long term durability) or a low VI base
stock heavily doped with VI improvers (bad, because of no long term
duarability).
Noack Volatility: a measure of ability of oil to not boil off the main
contributor to oil consumption IF the engine is mechanically sound.
HTHS (High temp high shear viscosity): simulates the oils viscoisity
under extreme heat and shear stress eg big ends when you are sitting on
the governor for hours on end or the rings traversing the bore surface
at high piston velocities.
Four ball wear test: three ball bearing are placed in a triangle and a
fourth is sat on top the top ball has a weight applied (usually but not
alway's 40kg) and is spun at (commonly 1500rpm) while the balls are
continuously flooded with fresh oil heated to typically 150 degrees C
(75 can be used but more commonly for gearbox oil). This makes a great
simulation of valvetrain wear.
I could go on I could also wear out my typing fingers. I will finish
with a quote from The Automotive lubricants reference book by Arthur
Caines and Roger Haycock. Within chapter 5 there is a section called
'Mislabeling (deliberate)' you can take from that what you want.
Craig.
Sorry for the novel. And there is a lot more to it than the above.
Roman wrote:
 
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Hi Guys
I was wondering if any one knew what the percentage of this failure in the
cruisers is.
By this I mean if 1000 were made how many developed this problem and was it
a clear case of the more in a given country the more cases would be seen in
that country.
Its seems to have only happened in the diesel 80s (why).
If the oil used was so important in the engines why didn't all the cruisers
that were made have the same problem every where except those in Japan.
What are the other factors in this failure of the BEBs, there must be some
or a lot because other wise all the cruisers would have had the exact same
problem, so why did it not happen to them all.
What is the difference between the BEBs that failed and the later ones that
did not fail, were they made of some thing different.
cheers
john 92HDJ 80 1HDT
 
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