Tegger's real-world oil consumption

Measuring engine oil consumption in this manner is difficult. While
you definitely can measure the volume of fluid in the crankcase, that
way not mean much unless you also know the make-up of the fluid in the
crankcase.

All piston engines consume some oil. They must. A thin layer of oil
remains on the cylinder wall on every piston stroke. Some of this is
burned during the combsution process, some vaporizes and leaves with
the exhaust, etc. Even in a very well sealed engine, more oil leaves
via the valve stems, the crank seals, through the PCV system, etc.
More of the original oil leaves as light components of the oil boil
away.

Balancing the oil that is consumed is comtamination added to the
crankcase via blow-by past the rings, through the PCV system, air
exchanged with the atmosphere, and in some cases minor leakage from
the cooling system. This contamination takes several forms - water,
unburned hydrocarbons, soot, dust particles, etc. Some of this
contamination ends up in the oil filter, but much of it remains
suspended in the "oil" in the crankcase. Some of these contaminates
have realtively low boiling points and can be driven off if you get
the "oil" hot enough. Others don't boil off. The fact that the oil
changes color is evidence that some contamination remians.

When you first change your oil, you have a crankcase full of pure oil.
A thousand miles later, the crankcase is now filled with a mixture of
oil, water, soot, unburned hydrocarbons, dust and ? If you check the
oil level immeadiately after a long drive which has rasied the
temperature of the oil above the boiling point of water, you can
assume that most of the water, and much of the unburned hydrocarbons
have been vaporized and are not immeadiately contributing to the oil
level in the crankcase. But soot, some unburned hydrocarbons, and dust
are still present. It seems reasonable to assume these are of only
minor significance, and that the decrease in oil level really does
represent oil consumed. However, if you check the oil after several
days of short trips in cooler weather, it is likely there is still
significant volumes of water and unburned hydrocarbons in the
crankcase contributing to the oil level. I am not sure how you can
manage the measuement process to consistently guarantee that you have
driven off the water and unburned hydrocarbons to the same extent?

You might think this is a trivial problem. I don't. On my farm we had
a very old gas tractor. The combustion rings did not seal well and the
tractor suffered from massive blow-by. We typically just used the
tractor to pull a trailer, or move a scoop load of grain for the cows
(it had a front end loader). Much of the time the oil level in the
crankcase stayed level or actually increased. Occasionally we would
work the tractor harder (for instance using the loader to move a pile
of dirt). In these cases, the oil level would drop dramitically. I
never bothered to have the oil analysed but I suspect that after just
a few months of light usage it included a very high percentages of
water and unburned hydrocarbons.

Another factor would be when and under what conditions you add make-up
oil. The rate of oil consumption should increase as the composition of
the oil in the crankcase changes. I believe that the "fresh" oil
probably has a realtively low given burn off rate. As the composition
of the oil changes, this burn off rate changes as well. What is left
of the original oil is likely more viscous and likely burns off at a
lower rate. However, the contamination that has accumulated in the oil
probably has a much higher burn off rate. So for a engine with weak /
worn rings and seals, the percentage of "original" oil steadily
decreases but at decreasing rate. I am guessing that you might see a
realtively quick decrease initially, followed by a long slow increase
in usage that levels out, asusming you add fresh oil regularly to
compensate for usage. At some point you are replacing contaminated
original oil with fresh oil in such a way that you reach a sort of
steady state composition (and burn off rate) for the oil.

Ed

 

translation: "even my dog left me so since i can't kick its ass anymore,
i'll be a prick on usenet instead".

so where is your oil consumption data big guy? and what have you ever
contributed?

more to the point, why are you even bothering? it's just freakin' oil
consumption. so freakin' whut? it's not freakin' rocket surgery.

idiot.

 

That is certainly good news about your dog.

 

not so good news that you're still a prick.

 

Try applying again.

 

You make some fair points.

I respond by posting my raw data. They are in an Excel file, here:
<http://www.tegger.com/hondafaq/misc/oil_consumption_.xls>

The first two columns give the actual miles driven during each test, and
the actual observed amount of oil used during that test.
(It must be noted that, in order to maintain consistency with the
"reported" mileage, the oil amounts are slightly adjusted. i.e.: 0.622 is
actually 0.6; 0.597 is also actually 0.6.)

I know you chose extremes in your example in order to make a point, but
now, having /real/ numbers to work with, you do the arithmetic, and tell me
what you get.

Remember that doing it my way, I get 1663 mi/qt. Doing it your way
gets...what number?

 

Definitely. 2,500-mile-old oil is darker and easier to see on the stick. I
do find it a bit difficult to locate the top of the "meniscus" with brand-
new oil, since it's so clear. It is possible that my second check is more
accurate than my first, for this reason.

A fresh batch of Mobil 1 went in this evening. I took the opportunity to
try and determine exactly where the "live" area of the dipstick was in
relation to the oil pan.

The bottom of the dipstick is, as far as I can measure, about an inch below
the bottom surface of the oil pan mounting flange. A bit below that point
is when the pan's "shallow" area suddenly takes a dip into the "deep" area.

The "shallow" area slopes downwards maybe 1/4" from the flywheel end to the
"deep" end, maybe a 6" distance. It then takes about a 12mm radius and then
heads straight down to the drain bolt.

Based on these observations, I believe the oil level does drop fairly
linearly, since there is no drastic change in oil pan shape from upper mark
on the stick to lower mark on the stick.

 

"Light components" of the oil do NOT "boil away". That is, flat-out, a
myth. I have this on /very/ good authority.

As for oil burn-off, well yes, that is precisely what I am trying to
measure.

Water is not an issue here, trust me. Fuel, however, is. The one analysis I
had done in 2005 indicated that I had about 2% dilution after 3,000 miles.

Soot and dust make up the smallest part of the oil, by far. There isn't
nearly enough there to affect the level.

 

sorry dude, your "authority" has that very wrong - they clearly have
never done fractional distillation.

that contradicts statement above...

that's not good, especially not for a vehicle making longer runs like
yours. did you rectify the problem?

 

Being that you wish to nitpick the method used in the subject test, I would
point out that what was described was a "method" NOT a "methodology"!!!!A
common mistake used even by those somewhat familiar with scientific testing.

DaveD

If you simply figure out how much the engine used over the entire

 

Yes what the OZP was described was a method. But you apparently
completely missed the point I was attempting to make. He is using the
wrong methodology. Yes I did make the mistake of critiquing some of the
methods also when I should have stayed with the main point which is that
the OP is using wrong methodology. Attempting to make more than one
point per posting tends to confuse the dim twitted.

The idea of using statistical analysis to solve what is really an
accounting problem is the wrong methodology. Let me give an analogy.
lets suppose you go to the grocery store and you put 42 items in your
shopping cart. When you get to the checkout counter you tell the clerk
that you are going to pick 17 items from the cart and through scientific
statistical analysis of the 17 picked items you are going to determine
how much you will pay the store. The clerk will inform you that is the
wrong methodology (more likely the store will just call the cops). It
doesn't matter if you argue that you are going to use well established
statistical methods and that you are extremely knowledgeable in regards
to scientific testing - the store will still insist that is a ridiculous
way to approach the problem.
The application of statistical analysis to solve what is a basic
accounting problem is using the wrong methodology. In the OP's case the
specific methods used also happen to be suspect, but even if the
statistical methods weren't flawed the fact remains - he's not using the
best methodology.

Once one has abandoned what is a ridiculously unreliable methodology
for this problem then you can start to think about the specific methods
one might choose to use. For instance, since the OP appears to be
numerically challenged he could account for the oil consumed in the
following way: He could keep all the containers that the oil comes in.
Then at 3000 miles when he drains the oil he could carefully and
thoroughly extract the oil from the oil pan and oil filter and put the
used oil back in the original containers to the original level. After
42000 miles simply divide 42000 by the number of empty containers to
determine that miles per quart number that he is looking for. No record
keeping or paper work will be necessary. And my strong suspicion is he
would arrive at a substantially different number than he is now.

-jim

 

so where are your results then asshole? i don't see a single fucking
number come from your dumb
fight-picking-because-you've-got-personal-problems ass.

 

You are retarded enough to qualify to be in a TV sit com. I just said
"This can be done with no record keeping no paperwork at all". And look
at your dumb response.
No wait a minute I take that back, - even in a TV sit com nobody would
believe someone could be that retarded.

-jim

 

This Excel data does not even look like the same data as the PDF. For
example, in your PDF file you have what is labeled a first reading at
321,771 miles and a second reading at 323,206 miles. That is an
interval of 1435 miles. I don't see any interval in the Excel file that
is even close to 1435. I see another 1st reading at 310,440 and a second
reading at 311,635 which is an interval of 1195. But I see nothing in
the excel file that corresponds with that number either. I'm sorry I
don't know what to make of your data. I don't know if you have a lot of
typos or arithmetic errors or if something else is going on.

I already told you the data is too spotty to actually know what the oil
consumption might be to any reasonable degree of accuracy. You should be
able to determine the consumption in 3000 to 6000 miles with much more
confidence in the accuracy than you can get from working with this data.
Whatever you are doing and whatever your engine is doing appears to be
fairly consistent. That much can be inferred from looking at the data.
But it looks to me that it is quite likely that your results could be
consistently wrong.

You can't do it my way with that data. That's my point - GIGO (look it
up if you don't know)

-jim

 

again, you entirely miss the point, asshole. the point is, since it
needs to be spelled out for your dumb retarded ass, is that you're just
a waste of electrons fucking whiner. you show up here with absolutely
**** NOTHING to contribute, and never have, yet something in your poor
perverted world of rectal/cranial inversion surgery tells you you have
something to say??? no wonder your wife left you.

 

so where is YOUR analysis, asshole? what - you don't have any? and you
can't do the stats? and you don't actually have a damned thing to say
other than whining loser bullshit? what a total non-surprise.

 

This would be a bad application for stats. I think the OP's study does
an excellent job of illustrating why statistical analysis can be an
exceptionally poor way to get a good answer. But what can you do - some
people are so misguided they will attempt to use statistical analysis to
tell them what day it is.

-jim

 

yeah. said by the contribution-free asshole that doesn't have the balls
to actually walk his talk.

 

Are you trying to champion stupidity?

I have been saying it is really dumb to use statistical analysis for
determining something that is a basic accounting problem like
determining oil consumption. And the only response you come up with is
"why don't you show us the statistical analysis of oil consumption you
have done". Are you saying If I can't match your stupidity - I shouldn't
post?

I apparently don't have what it takes to be as dumb as you that is for
sure.

 

well, not only are you too fucking useless to step up to the plate when
called, you either can't read, or you're trying to deceive by putting
false words in my mouth.

well one of us sure is dumb. and it sure isn't the one that can't read
or tries to deceive.