Matt Lang wrote:
Had a look at the chart, what's the issue???


No issue, i just wanted to see how much oil the 2 stroke actually
used. The benchmark is a 4 stroke motor which is usually is not known
as "uses oil".

I didnt want to fel bad ripping around burning loads of oil, thus I
want to see how much i am useing compared to if I had bought a 4
stroke. The boat and the other motorized toys are getting winterized
(( So I have lots of time on my hand for these kind of questions



It confirms that the modern 2 strokes use less oil than the older ones,
but this is an allusion really when you take into account the extra


No, actually it doeasnt, unless you consider the optimax old desogn.
The optimax is an older design and the first generation DFI. Lets see
to how many generations they will actually make it ...

The chart shows Merc Optimax, Whoevers (Bombardier?) ETec, and Mercs 4
stroke Verado. The oldest design there is the optimax. All of the
above use less oil as a conventional 2 stroke.



costs & while the dealers won't admit it you "should" clean the holding
tank every year. Once in there oil subject to heat & moisture
deteriorates into sludge with even the smallest amounts of water.


This is a very good point which I will investigate right away in order
to keep my motor happy This flushing procedure can be done with
cheap oil or maybe other suitable substances. Do you have any
procedure or recommendation?
In the end it may be cheaper to buy a new oil tank? This needs to be
looked into.

I wouldn't think "flushing" would be needed indeed the suggestion here
is not to risk touching the existing hose fittings etc for fear of
creating a leak. Also even a small air lock can be trouble.



Again "all" the oil in a 2 stroke (by your graph the same or more than
a 4 stroke) still goes somewhere, either burnt or out the exhaust as raw
oil, I accept what you say about oily rags etc but we're talking the
entirety of the oil, not just sundry cleanup wipes.


Yes correct. This point was not looked at in my comaprison and was not
intended to be looked at. It is a very important and valid point
though. Someone needs to create an eco balance to see whats worse in
the end. If 4 stroke oil is recycled then thats best. If its done
like some people I know do by not recycling or just recycling the oil
but not the filter and rags then it maybe worse than the 2 stroke just
burning it up.


There is another issue with the dfi 2 strokes & their oil, it's related
to raw oil injected into the crankcase, the oil builds up till excess is
"transferred", it either then gets burnt or goes straight through the
exhaust as raw oil.


I see no serious issue. Exactly that happens with conventional 2
strokes ... of course in general its not good that 2 strokes burn oil
...

A conventional 2 stroke even an efi that injects raw oil, still "mixes"
it with fuel in the crankcase & it's in those premises that I was
suggesting the oil itself doesn't get the chance to lie around getting
hot, whereas the situation is slightly different with the DFIs, it can &
does.


The system injects very small amounts at idle or
even low revs, however the oil is subject to considerable heat buildup,
unlike 4 strokes oil or even an old tech 2 stroke when it was diluted
with fuel & traveled through the engine relatively quickly. This is why
they've promoted special oils, because the oil can get hot enough to
bake behind the rings & it's all down hill from there.


Yes the DFI motors need the expensive oil. I only know the optimax
and it partly recycles its oil, which is good but this requires
different oil then the normal 2 stroke uses which is bad, as the
recirculated oil must be made so it doesnt break down from it
(expensive).



Harry is a liar & has never actually owned a boat much less an optimax
engine. As for his old "hundreds of hours" lie, when he fabricated that
phantom boat in 98 he claimed here after a few mths use he had 200 hours
on it, it's just more evidence of a total lie.


Its not for me to judge that. I can not see a reason that would make
people claim they have owned certain boats and motors which they
actually havent. But to each their own.

Karen, I appreciate the discussion with you and the points you bring
in! You seem to be more knowledgable about the subject as ... lets say
... the average female (and in fact male)... Dont take this wrong,
this isnt sexist talk!

Whats your background and your background with motors if I may ask?

When the DFI were released we (we is the blokes I work with) took a
particular interest because for literally years before we'd been
watching Orbital the promoters of the optimax system, & Ficht trying to
flog their systems around the major engine manufacturers. Ficht was
originally promoted as a diesel injection system & orbital even got Ford
to run a test fleet of small cars on orbital 2 strokes.

Particularly Orbital in our view were all froth & bubble they made
extravagant claims in the local press releases it seemed every second
Wednesday; they claimed Ford were about to adopt it, then even the son
of the bent Indonesian ruler at the time Sohato was said to be going to
build cars with orbital engines & teach Detroit a thing or two:-) it
would have been hilarious had it not sucked endless sad investors of
their money.

Never once would Orbital deal with the common call from almost everyone
in the local industry of "how do you say you've dealt with the problem
of heat buildup when engines are run lean???", they usually muttered
something about extra atomisation happening in that primary manifold
from the air pump, however it didn't work.

We also watched their patent applications closely (when I say we we're
"interested" I mean we had a definite interest:-)). After a while &
particularly after Ford dismissed it as nonsense, we noticed most of
their filings were related to solutions to problems that were of their
own making, indeed we felt every ad hoc "fix" they seemed to dream up
would just lead to more questions than solutions.

As for Ficht it was much more easily identified as doomed, it's
original patents involved pumping fuel (diesel in this case) around a
closed rail at high velocity, then electromagnetically slamming a valve
shut in it's path, the impact shock created pressure waves in the system
(exactly like water pipe hammer when the washing machine valve slams
shut) they claimed the peaks of which could be harvested by an injector
nozzle. Of course anyone who knew the slightest about the amount of
energy & force needed to create sudden extreme pressure rises, that
could be sustained over the period of time a diesel needs to inject
fuel, immediately dismissed it as nonsense (Germany the home of fuel
injection didn't even give it a second glance).

The Ficht principle is the same as water hammer in domestic plumbing or
pressure spikes in hydraulic systems i.e. very well known & understood,
it's a bother & can cause damage but as soon as there's an outlet for
"spikes" (usually a simple damper) the pressure goes away. Ficht is an
attempt to get a great pressure rise over a very short period & do it
essentially for no energy input. Something for nothing??? not likely in
this universe as we currently know it:-)

We were more than a little bemused when Brunswick & OMC announced they
had signed up with orbital & ficht respectively, the orbital was as it
was & the Ficht they'd changed the execution so instead of suddenly
stopping fuel at high velocity they just struck a solid ball to great
the shock waves.A bit like dropping a rock in a bucket of water, the
waves created go over the edge.

Ficht failed spectacularly as predicted because the impact pressure
rise was never going to supply enough pressure rise to give proper
atomisation, coupled with the lean mixtures it had a serious
failure rate & as I said was doomed from the beginning. Optimax faired a
little better but still had the problem of low injection pressure (they
use a normal injector pressure but unlike a normal injector into a
vehicle manifold (which is usually below atmospheric pressure) they
inject against the pressure of the output from the additional air pump,
so the atomisation problem remains, as does the question of lean mixture
heat buildup.

Both technologies are by now totally discredited, Brunswick are clearly
going 4 stroke throughout the range & Ficht brought OMC down, then Bomb
(who have some proper engineers) got rid of it, now in a last desperate
gasp E-tec will try to mitigate against the symptoms by using ever more
heat resistant oil & pistons that will not "melt" till a higher temp:-)

Sorry to smile but it's absurd!!! if petrol sees any temp around or
above 250C it auto ignites (detonates), even the lowliest of aluminium
is good to well over 600C. So their latest suck it & see try is as
doomed as the original Fichts & for the exact same reasons;

(i) The impact shock injectors can never create enough pressure to
properly atomise the fuel (Yamaha need 800 psi & they are also going to
4 strokes).

(ii) The so called injector is not an injector at all but not much
better than a flap valve/garden hose nozzle, it will only open when the
combustion chamber pressure is well below the pressure in the shock
injectors. At power they "try" to start injection up to 240degs BTDC
i.e. before the previous charge has even uncovered the exhaust ports.

(iii) The continuous firing of the spark is just the same confirmation
of how lean the mix is at low to med revs & of course it means accurate
timing of the actual ignition point is impossible, this means some
firing will be as intended others very late, just so long as there isn't
a "miss" because then they fail the EPA.

(iv) The latest sensor to detect abnormal combustion (knock sensor) is
proof positive they're well aware of the issue, however it's also proof
they still don't understand the real cause of the engine failures.

(v) It's long been known (mainly from aircraft engines, but also some
attempts with car engines Chrysler, Honda & Mitsubishi) that engine can
run on very lean mixtures, however the "abnormal" combustion leads to
heat buildup in the chamber surfaces. Usually an engine running very
lean will not detonate while still extremely lean (i.e. their latest
sensor will not sense anything), but this doesn't stop the chamber
surfaces getting overly hot.

(vi) In an OB 2 stroke the head can be kept very cool being alloy &
having an endless supply of cool water, but the piston/rings in a 2
stroke is almost totally uncooled. Once the piston temps gets over 250C
(not very hot really) then auto ignition is a certainty but while lean
probably no harm done, simply because there isn't enough fuel present.

(vii) The trouble starts when the power is quickly increased above the
lean burn mode, suddenly there is plenty of fuel available & this sudden
excess fuel rather than cool the piston just auto ignites but now it
will lead to full on detonation = more heat = more detonation etc etc bang.

(viii) Their new sensor will detect this but what can it really do???
retard the spark timing?? too late the overly hot piston is causing the
auto ignition not the spark timing; increase the mixture??? again too
late it's the sudden influx of fuel onto the overly hot surface that set
the full detonation going in the first place; what's left??
electronically lower the power?? well consumers won't be impressed with
their engine slowing when they suddenly give it full throttle.

It's instructive to see how the same lean mixtures problem has been
approached by others over many years;

(a) The car people Chrysler, Honda, Mitsubishi & Mercedes have all gone
to extreme lengths to guard against excess heat being built up while the
engine is in lean mode, mostly this limits lean mixtures to idle (no
power at all) over run, (No power at all & boat motors don't have it
anyway) or very light throttle high speed cruise (again hardly any power
at all, most cars it's when the EGR (exhaust gas recirculation) is
engaged, so the average modern slippery sedan needs about 30hp to hold
it at 65mph (flat road blah blah blah) & this is usually around
1800-2000 rpm or 12-15% of max power at about 35-40% of max revs i.e.
the cyl pressure is extremely low with lots of air (& exhaust) going
through keeping the chamber cool. (a boat motor has no very light load
high speed cruise, as the revs rise so does the load from the prop it
increases at a steepening rate) All these precautions yet they're all 4
strokes (half the number of firings & plenty of oil under the piston to
carry the heat away).

(b) The piston aircraft engines are also run lean although never
anything like as lean as Ficht & Optimax claim. Aircraft lean as
the air density lowers with altitude so they're not really very lean at
all & allowing that they're big slow turning essentially lazy
engines, even so they still run the risk of having heat buildup in the
chamber when operated too lean, so pilots are trained never to recover
from lean cruising by just giving the engine full rich mixture & more
throttle (exactly what happens when an OB is suddenly powered up after a
long run in the lean mode). Pilots are trained to richen the mixture
slowly as the power is slowly increased, this is to give the chamber
temps time to normalise as the extra fuel is added; just in case:-)



You are also welcome to email me. My email as posted is real.

Sorry to be so long again, but this subject has been a war since 98 &
it seems till Brunswick are all 4 stroke & E-tec has failed it will
continue.


Mine isn't; the name is OK but it's tpg com au

K

Matt