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?what causes wear in generator engines?
|
|
| philkryder 2006-01-29, 4:21 pm |
| During my recent research into generators, I noticed that they heavy
duty prime movers listed piston speed and travel in their specs.
This caused me to wonder.
The "stroke" on a 2-71 Detroit is 6 inches.
The stroke on a new Cat C15 is over 7 inches.
At 1800 RPM, the Detroit piston moves 1800 feet (12 inches per
revolution) per minute.
The Cat would move even more.
Meanwhile, the stroke on our little briggs tri-fuel is just under 2.5
inches.
At 3600 RPM it travels fewer than 1500 feet in a minute...
So the relative piston speed is about 16% less in the Briggs compared
to the Detroit.
Similarly, the Rod and main Journals on the big prime movers are more
than twice as large in diameter as the Briggs.
The propane fuel keeps the oil cleaner on the tri-fuels.
And all the engines can use high quality synthetics with with viscosity
ranges and good film strenghts.
And all the engines can have low oil and high temp shutdowns...
And with the small oilsump capacity, we can change the oil in the small
engine as frequently (or more frequently ) as the big ones at less
cost.
Yet, I don't think that there is any reasonable expectation that the
Briggs would last even a tenth as long as a new CatC15 or even
venerable Detroit...
So, ??Where does the WEAR come from in these generator Wares??
puzzled.
THanks
Phil
| |
| Antipodean Bucket Farmer 2006-01-29, 6:21 pm |
| In article
<1138564875.092887.166240@f14g2000cwb.googlegroups.com>
, alt.google@Kryder.com says...
> During my recent research into generators, I noticed that they heavy
> duty prime movers listed piston speed and travel in their specs.
>
> This caused me to wonder.
>
> The "stroke" on a 2-71 Detroit is 6 inches.
> The stroke on a new Cat C15 is over 7 inches.
>
> At 1800 RPM, the Detroit piston moves 1800 feet (12 inches per
> revolution) per minute.
> The Cat would move even more.
>
> Meanwhile, the stroke on our little briggs tri-fuel is just under 2.5
> inches.
> At 3600 RPM it travels fewer than 1500 feet in a minute...
> So the relative piston speed is about 16% less in the Briggs compared
> to the Detroit.
>
> Similarly, the Rod and main Journals on the big prime movers are more
> than twice as large in diameter as the Briggs.
>
> The propane fuel keeps the oil cleaner on the tri-fuels.
>
> And all the engines can use high quality synthetics with with viscosity
> ranges and good film strenghts.
>
> And all the engines can have low oil and high temp shutdowns...
> And with the small oilsump capacity, we can change the oil in the small
> engine as frequently (or more frequently ) as the big ones at less
> cost.
>
> Yet, I don't think that there is any reasonable expectation that the
> Briggs would last even a tenth as long as a new CatC15 or even
> venerable Detroit...
>
> So, ??Where does the WEAR come from in these generator Wares??
Offhand, I would guess two factors. Quality of the
metal, and precision of the parts fitting together.
--
Get Credit Where Credit Is Due
http://www.cardreport.com/
Credit Tools, Reference, and Forum
| |
| Allison-nospam@nouce.bellatlantic.net 2006-01-29, 6:21 pm |
| On 29 Jan 2006 12:01:15 -0800, "philkryder" <alt.google@Kryder.com>
wrote:
>During my recent research into generators, I noticed that they heavy
>duty prime movers listed piston speed and travel in their specs.
>
>This caused me to wonder.
>
>The "stroke" on a 2-71 Detroit is 6 inches.
>The stroke on a new Cat C15 is over 7 inches.
>
>At 1800 RPM, the Detroit piston moves 1800 feet (12 inches per
>revolution) per minute.
>The Cat would move even more.
>
>Meanwhile, the stroke on our little briggs tri-fuel is just under 2.5
>inches.
>At 3600 RPM it travels fewer than 1500 feet in a minute...
>So the relative piston speed is about 16% less in the Briggs compared
>to the Detroit.
>
>Similarly, the Rod and main Journals on the big prime movers are more
>than twice as large in diameter as the Briggs.
>
>The propane fuel keeps the oil cleaner on the tri-fuels.
>
>And all the engines can use high quality synthetics with with viscosity
>ranges and good film strenghts.
>
>And all the engines can have low oil and high temp shutdowns...
>And with the small oilsump capacity, we can change the oil in the small
>engine as frequently (or more frequently ) as the big ones at less
>cost.
>
>Yet, I don't think that there is any reasonable expectation that the
>Briggs would last even a tenth as long as a new CatC15 or even
>venerable Detroit...
>
>So, ??Where does the WEAR come from in these generator Wares??
>
>puzzled.
>THanks
>Phil
One word, heat.
Most of the smaller gens are aircooled and rely on wider tolerences to
withstand the range of temp they experience. Water cooled engines
run at far more consistant temps and generally cooler as well so
closer tolerences are resonable and wear longer.
Allison
| |
|
|
<Allison-nospam@nouce.bellatlantic.net> wrote in message
news:nfcqt1hekabbvv3gk24ai8goraetumd5gu@4ax.com...
> On 29 Jan 2006 12:01:15 -0800, "philkryder" <alt.google@Kryder.com>
> wrote:
>
>
> One word, heat.
>
> Most of the smaller gens are aircooled and rely on wider tolerences to
> withstand the range of temp they experience. Water cooled engines
> run at far more consistant temps and generally cooler as well so
> closer tolerences are resonable and wear longer.
>
> Allison
I would agree with the heat principal to a larger extent.
Also the larger engines once started have enough mass in motion that they
are not constantly governing themselves up and down for the load.
I would imagine that if someone blue printed a 3600 rpm engine that it could
last a lot longer. Of course COST come in as a huge factor on them.
I have a 35 year old 5 hp Briggs attached to an Pincor 2k generator. Head,
valves rings and bearing have been replaced once. This was a daily runner
for the first 15 years of its life. I have changed the oil religiously
every 40 hours or once a week when it was being used. The bolts near the
exhaust are fused and every one has refused to fix the muffler. (more than a
tad loud now days)
This was an cast iron block B&S. The new ones are not made like this one
was. I will replace it someday. But it is going to have to break first. I
will definitely go with a water buffalo when it comes time.
| |
| George Ghio 2006-01-29, 7:21 pm |
| Metallurgy is a good start
philkryder wrote:
> During my recent research into generators, I noticed that they heavy
> duty prime movers listed piston speed and travel in their specs.
>
> This caused me to wonder.
>
> The "stroke" on a 2-71 Detroit is 6 inches.
> The stroke on a new Cat C15 is over 7 inches.
>
> At 1800 RPM, the Detroit piston moves 1800 feet (12 inches per
> revolution) per minute.
> The Cat would move even more.
>
> Meanwhile, the stroke on our little briggs tri-fuel is just under 2.5
> inches.
> At 3600 RPM it travels fewer than 1500 feet in a minute...
> So the relative piston speed is about 16% less in the Briggs compared
> to the Detroit.
>
> Similarly, the Rod and main Journals on the big prime movers are more
> than twice as large in diameter as the Briggs.
>
> The propane fuel keeps the oil cleaner on the tri-fuels.
>
> And all the engines can use high quality synthetics with with viscosity
> ranges and good film strenghts.
>
> And all the engines can have low oil and high temp shutdowns...
> And with the small oilsump capacity, we can change the oil in the small
> engine as frequently (or more frequently ) as the big ones at less
> cost.
>
> Yet, I don't think that there is any reasonable expectation that the
> Briggs would last even a tenth as long as a new CatC15 or even
> venerable Detroit...
>
> So, ??Where does the WEAR come from in these generator Wares??
>
> puzzled.
> THanks
> Phil
>
| |
| Cap Group 2006-01-29, 9:21 pm |
| You are taking the "average speed" of the piston, as if it was constant. It
is not. The length of the connecting rod will determine the
acceleration/deceleration rate of the piston. The longer the connecting rod
is, the more gradual the acceleration/deceleration rate will be and thus the
longer the engine will live (all things being equal). Racing engines
usually want to have high acceleration rate for the piston, as it helps to
generate a 'Vacuum under the valve faster to get the air moving( there are
other combustion issues too!). As such,racing engines will have a short
connecting rod. Sometimes the rod is so short that the skirt of the piston
has to be cut away, to allow the counterweights of the crank to pass by the
piston, when it's at the lower edge of the stroke.. Usually the high hp/wt
engines have the short rod lengths.
As the rod length gets longer, the rate of acceleration will get less, the
instantaneous speed of the piston will go down and wear (and ring flutter)
will also lessen. Also the 'Torque' of the engine will usually increase.
There are exceptions, but this basically applies.
An other factor to a short con rod, is the piston will have a higher side
load on the thrust side due to the higher angle of the rod during the
stroke. This will increase the wear on the piston skirt./cyl wall boundary.
Conversely, as the rod gets longer, the angle of the push on the piston will
get less, and the side load will be reduced, increasing engine life.
Rule of thumb.. Big and heavy is good for a long time... Small and light
is good for intermittent use!
CAP
"philkryder" <alt.google@Kryder.com> wrote in message
news:1138564875.092887.166240@f14g2000cwb.googlegroups.com...
> During my recent research into generators, I noticed that they heavy
> duty prime movers listed piston speed and travel in their specs.
>
> This caused me to wonder.
>
> The "stroke" on a 2-71 Detroit is 6 inches.
> The stroke on a new Cat C15 is over 7 inches.
>
> At 1800 RPM, the Detroit piston moves 1800 feet (12 inches per
> revolution) per minute.
> The Cat would move even more.
>
> Meanwhile, the stroke on our little briggs tri-fuel is just under 2.5
> inches.
> At 3600 RPM it travels fewer than 1500 feet in a minute...
> So the relative piston speed is about 16% less in the Briggs compared
> to the Detroit.
>
> Similarly, the Rod and main Journals on the big prime movers are more
> than twice as large in diameter as the Briggs.
>
> The propane fuel keeps the oil cleaner on the tri-fuels.
>
> And all the engines can use high quality synthetics with with viscosity
> ranges and good film strenghts.
>
> And all the engines can have low oil and high temp shutdowns...
> And with the small oilsump capacity, we can change the oil in the small
> engine as frequently (or more frequently ) as the big ones at less
> cost.
>
> Yet, I don't think that there is any reasonable expectation that the
> Briggs would last even a tenth as long as a new CatC15 or even
> venerable Detroit...
>
> So, ??Where does the WEAR come from in these generator Wares??
>
> puzzled.
> THanks
> Phil
>
| |
| Johnny 2006-01-29, 9:21 pm |
| Is it the acorn shells the squirrels leave in there?
"philkryder" <alt.google@Kryder.com> wrote in message
news:1138564875.092887.166240@f14g2000cwb.googlegroups.com...
> During my recent research into generators, I noticed that they heavy
> duty prime movers listed piston speed and travel in their specs.
>
> This caused me to wonder.
>
> The "stroke" on a 2-71 Detroit is 6 inches.
> The stroke on a new Cat C15 is over 7 inches.
>
> At 1800 RPM, the Detroit piston moves 1800 feet (12 inches per
> revolution) per minute.
> The Cat would move even more.
>
> Meanwhile, the stroke on our little briggs tri-fuel is just under 2.5
> inches.
> At 3600 RPM it travels fewer than 1500 feet in a minute...
> So the relative piston speed is about 16% less in the Briggs compared
> to the Detroit.
>
> Similarly, the Rod and main Journals on the big prime movers are more
> than twice as large in diameter as the Briggs.
>
> The propane fuel keeps the oil cleaner on the tri-fuels.
>
> And all the engines can use high quality synthetics with with viscosity
> ranges and good film strenghts.
>
> And all the engines can have low oil and high temp shutdowns...
> And with the small oilsump capacity, we can change the oil in the small
> engine as frequently (or more frequently ) as the big ones at less
> cost.
>
> Yet, I don't think that there is any reasonable expectation that the
> Briggs would last even a tenth as long as a new CatC15 or even
> venerable Detroit...
>
> So, ??Where does the WEAR come from in these generator Wares??
>
> puzzled.
> THanks
> Phil
>
| |
| Joe Cool 2006-01-29, 11:21 pm |
|
"philkryder" <alt.google@Kryder.com> wrote in message
news:1138564875.092887.166240@f14g2000cwb.googlegroups.com...
> During my recent research into generators, I noticed that they heavy
> duty prime movers listed piston speed and travel in their specs.
>
> This caused me to wonder.
>
> The "stroke" on a 2-71 Detroit is 6 inches.
> The stroke on a new Cat C15 is over 7 inches.
>
> At 1800 RPM, the Detroit piston moves 1800 feet (12 inches per
> revolution) per minute.
> The Cat would move even more.
>
> Meanwhile, the stroke on our little briggs tri-fuel is just under 2.5
> inches.
> At 3600 RPM it travels fewer than 1500 feet in a minute...
> So the relative piston speed is about 16% less in the Briggs compared
> to the Detroit.
>
> Similarly, the Rod and main Journals on the big prime movers are more
> than twice as large in diameter as the Briggs.
>
> The propane fuel keeps the oil cleaner on the tri-fuels.
>
> And all the engines can use high quality synthetics with with viscosity
> ranges and good film strenghts.
>
> And all the engines can have low oil and high temp shutdowns...
> And with the small oilsump capacity, we can change the oil in the small
> engine as frequently (or more frequently ) as the big ones at less
> cost.
>
> Yet, I don't think that there is any reasonable expectation that the
> Briggs would last even a tenth as long as a new CatC15 or even
> venerable Detroit...
>
> So, ??Where does the WEAR come from in these generator Wares??
>
> puzzled.
> THanks
> Phil
>
Compare the oil filters, Cat - Detroit etc there massive the briggs, there
nonexistent.
Snoopy Joe
| |
| Mr Wizzard 2006-01-30, 2:21 am |
|
"philkryder" <alt.google@Kryder.com> wrote in message
news:1138564875.092887.166240@f14g2000cwb.googlegroups.com...
> During my recent research into generators, I noticed that they heavy
> duty prime movers listed piston speed and travel in their specs.
>
> This caused me to wonder.
>
> The "stroke" on a 2-71 Detroit is 6 inches.
> The stroke on a new Cat C15 is over 7 inches.
>
> At 1800 RPM, the Detroit piston moves 1800 feet (12 inches per
> revolution) per minute.
> The Cat would move even more.
>
> Meanwhile, the stroke on our little briggs tri-fuel is just under 2.5
> inches.
> At 3600 RPM it travels fewer than 1500 feet in a minute...
> So the relative piston speed is about 16% less in the Briggs compared
> to the Detroit.
>
> Similarly, the Rod and main Journals on the big prime movers are more
> than twice as large in diameter as the Briggs.
>
> The propane fuel keeps the oil cleaner on the tri-fuels.
>
> And all the engines can use high quality synthetics with with viscosity
> ranges and good film strenghts.
>
> And all the engines can have low oil and high temp shutdowns...
> And with the small oilsump capacity, we can change the oil in the small
> engine as frequently (or more frequently ) as the big ones at less
> cost.
>
> Yet, I don't think that there is any reasonable expectation that the
> Briggs would last even a tenth as long as a new CatC15 or even
> venerable Detroit...
>
> So, ??Where does the WEAR come from in these generator Wares??
Believe it or not, it comes from "acid", and corosion...
85% of an engines wear (top cylinder) comes from
the acid (etching) from the explosion by-product of
a cold engine. That is why it is always recommended
to run an engine for at least 3 minutes before applying
a load (at least in automobiles) to help minimize wear.
>
> puzzled.
> THanks
> Phil
>
| |
| philkryder 2006-01-30, 4:21 am |
| for what?
And to what effect?
What are the differences and what do they cause?
George Ghio wrote:[color=darkred]
> Metallurgy is a good start
>
> philkryder wrote:
| |
| philkryder 2006-01-30, 4:21 am |
| Can you clarify just a bit?
Isn't the speed of the piston proportional to the lenght of the stroke
and the sine of the crank angle?
And isn't accelleration proportional to the cosine of the crank angle?
How are piston speed and accelleration affected by rod length?
Cap Group wrote:[color=darkred]
> You are taking the "average speed" of the piston, as if it was constant. It
> is not. The length of the connecting rod will determine the
> acceleration/deceleration rate of the piston. The longer the connecting rod
> is, the more gradual the acceleration/deceleration rate will be and thus the
> longer the engine will live (all things being equal). Racing engines
> usually want to have high acceleration rate for the piston, as it helps to
> generate a 'Vacuum under the valve faster to get the air moving( there are
> other combustion issues too!). As such,racing engines will have a short
> connecting rod. Sometimes the rod is so short that the skirt of the piston
> has to be cut away, to allow the counterweights of the crank to pass by the
> piston, when it's at the lower edge of the stroke.. Usually the high hp/wt
> engines have the short rod lengths.
> As the rod length gets longer, the rate of acceleration will get less, the
> instantaneous speed of the piston will go down and wear (and ring flutter)
> will also lessen. Also the 'Torque' of the engine will usually increase.
> There are exceptions, but this basically applies.
> An other factor to a short con rod, is the piston will have a higher side
> load on the thrust side due to the higher angle of the rod during the
> stroke. This will increase the wear on the piston skirt./cyl wall boundary.
> Conversely, as the rod gets longer, the angle of the push on the piston will
> get less, and the side load will be reduced, increasing engine life.
> Rule of thumb.. Big and heavy is good for a long time... Small and light
> is good for intermittent use!
> CAP
>
> "philkryder" <alt.google@Kryder.com> wrote in message
> news:1138564875.092887.166240@f14g2000cwb.googlegroups.com...
| |
| barry@sme-online.com 2006-01-30, 12:21 pm |
| There are formulas to determine if a given engine is high/med/low
speed. Depends on stroke and normal operating rpm, but results in EMD
567 being categorized as "high speed" at 750 rpm. Then, some ALCOs with
2.5" longer stroke were rated for full load at 1000 rpm, and are
considered more durable than comparable EMDs, by many.
Lots of design details enter into longevity estimates:
1. cast-iron cylinder face has lots of microscopic inclusions, from
graphite in the melt, that help greatly to retain lube; steel does not.
2. for diesel, compression rings are obviously critical, both in terms
of metallurgy and geometry.
3. for diesel again, bottom-end can be greatly stressed, and is also
critical.
4. especially for diesel, cleanliness (filtering) of lube oil is
critical at the ring-bore interface, in addition of course to be
properties of the lube itself. Wear can be rapid. Dilution of lube by
fuel oil is a serious no-no, so injectors matter too.
J
| |
| barry@sme-online.com 2006-01-30, 1:21 pm |
| Not really so for gasoline engine, in fact the converse- the best way
to properly warm it up is under moderate load.
For diesels, the problem is to get them warmed up without load. Thus
many mfgs of generator sets recommending that test-runs be under load
for sufficient time to get engine up to temp. Anything that displaces
lube from ring-bore interface, most especially at the top of the
ring-travel is to be avoided at all cost.
J
| |
| George Ghio 2006-01-31, 9:21 am |
| Back in the late fifties Briggs produced an all cast iron motor.
Somewhere along the line they changed to alloy with a chrome bore.
Thus earning the name Bogged and Stricken. Even later in the game they
started the Vanguard line. This I've been told is made by Mitsubishi to
the specs supplied by Briggs.
The thing is that I own a Vanguard and a Mitsubishi. The blocks are
almost identical.
The Vanguard is around six years old, the Mitsubishi around fifteen
years old.
The Vanguard was back to the shop three times in the first twelve
months. Burned the exhaust valve twice. Problem solved when I stellited
the valve face and reground it, The valve seat is beginning to erode
away causing pocketing of the valve.
The Mitsubishi is worn out. But, still runs, starts on the second pull
and has never been opened up. Petrol, oil and the occasional spark plug
have been the only requirement. The valves and seats are of much better
quality. In fact the whole motor seems to be made of better materials
than the Vanguard.
If I was to make a choice I would rather pay the Vanguard's price.
OTOH when it comes to owning, I'll have the Mitsubishi thank you very much.
I don't know what Briggs specified for the Vanguard, I do know that the
materials used are inferior to those used by Mitsubishi.
Then most of the other posts are correct as to tolerances, oiling etc.etc.
Mostly, if you get more than a thousand hours out of a motor you are
doing well.
By the way, when I was around ten (1960) I had a Briggs that was given
to me. It was seized. I pulled the lid off, put a block of wood on top
of the piston and whacked it with a hammer until the piston was free.
Put the lid back on and ran the motor for several hundred hours before I
gave it to friend for his bicycle.
Treat a modern Briggs that way and you will have a pile of junk.
Detroit don't skimp on the materials they use.
philkryder wrote:
> for what?
> And to what effect?
> What are the differences and what do they cause?
>
> George Ghio wrote:
>
>
>
| |
| m Ransley 2006-01-31, 11:21 am |
| Diesel fuel lubricates the valves and cilinder walls before it is
ignited, gasoline dilutes oils efectivness , propane- Ng may acutaly be
harder on valve and head from dryness but much easier on lower end from
non contamination of oil. This is what a friend told me who long term
runs a propane Chevy 350 pickup. So Deisel lubes, Propane makes lower
end last but is harder in upper end-cilinder and valves.
Water cooled operate at a minimum temp range and dont overheat, air
cooled are built looser and easily run hot in certain environments where
a water cooled would not. Quick warmup of watercooled and even operating
temps allow all metal to have expanded to proper specs for longer life
from proper lubrication and proper tolerances.. I know on my Generac
7500 I can easily get the exuast to glow bright red on full load warm
days, from what little I know of Bright Red s steel temp it must be Hell
inside that aluminum engine, near meltdwn, shortening its life at that
extreme temp.
Deisels must be warmed up first. BMW recomends the best scenario to
warm a motor would be driving a slight incline at low rpm. As for oil go
Mobil 1, it is the only oil most often recommended by the best car
manufacturers , it has the tests to prove minimal wear at 100000 miles
by BMW. I know you use Castrol but people I know that sell competing
Racing oils , and not Mobil say Mobil 1 oil is truely a superior product
My car is driven hard a 4 cil camry , at over 100000 at its lastest
required EPA test the polution numbers are like it was almost last year,
at its wear rate it has 75% life left, but I wont be driving it 30 more
years, car cancer-salt.
Your other factor is internal stress loads At highway the car uses
10-15% power 1900 rpm which equals low internal stress, Your Generac
pulls at how you sized it maybe 40-75 load, 3600 rpm, which equals low
life from major continual stress and high rpm. There is a factor of Rpm
and engine life I cannot explain but it is there.
| |
| Mr Wizzard 2006-01-31, 3:21 pm |
|
<barry@sme-online.com> wrote in message
news:1138637760.627653.156710@g14g2000cwa.googlegroups.com...
> Not really so for gasoline engine, in fact the converse- the best way
> to properly warm it up is under moderate load.
Could be, but I'm not sure there is such a thing as
"moderate load" in an automobile/light truck; most
prople put er in gear, and off to jack-rabbit starts
out of the driveway/stop light on their busy way.
I think the idea of warming up a car engine no-load
in the driveway is to let it come up to temp as quick
as possible while at fast(er) idle so that the corrosive
byproducts are "on the move" instead of being under
and load to where pistons are being asked to bear more
load against the cylinder in this highly corrosive environment
during cold warmup. Also, the ECM's are dumping mass
amounts of fuel into the engine during this initial cold-start
mode making matters worse thus why I would think you'd
want no-load, high volume air/misture/exhaust air/gas as
to keep the upper cylinder purged as best as possible while
the thing heats up to get past this corrosive stage as soon as
possible. But who knows - I've only seen limited white
papers on this subject, and actual lab testing results are
hard to come by on any modern engines. When I say
"modern", I mean the newer gas car engines where they
have that new short "land width" of ~3 mm of the top piston
ring to reduce combuston gas "dead zone". Interesting stuff...
>
> For diesels, the problem is to get them warmed up without load. Thus
> many mfgs of generator sets recommending that test-runs be under load
> for sufficient time to get engine up to temp. Anything that displaces
> lube from ring-bore interface, most especially at the top of the
> ring-travel is to be avoided at all cost.
>
> J
>
| |
| philkryder 2006-02-01, 12:21 am |
| I'm not really concerned about automobiles. - Just trying to figure out
the Generator thing.
I can see the tolerances and heat issues for air cooled.
And the valve and valve seat heat - though you would think that folks
building the engines could get enough cooling via the air fins if they
tried...
Our warmup is zero to 3600 rpm - the engine has no low idle in this
setup.
Some seem to think that is bad.
I'd like a low speed idle, but don't know how to get it.
It seems the best we could do on our part is
1) clean and good oil
2) run well below max load to avoid overheating valves and top end.
I'm beginning to think that our Honda ES 6500 were the victims of "load
creep" over the years.
Perhaps made worse by some ill thought out attemps to use heavier
weight oils which resulted in more oil pumping load and sheared oil
drive pump gears.
Interestingly, because we are running at 3300foot altitude - we lose
about 10% max power, but, max pressure and heat are reduced, which
should mean it is just plain impossible for us to run at the max
designed load of the engine...
I read somewhere about momentum increasing with the square of the
rotational velocity. Perhaps forces on the bearings also increase with
the square. And valve seat contact time and cooling might be less in
the higher RPMS engines...
Still, I'd be happy if I could get one tenth - let alone one fourth the
life of a high quality diesel...
Thanks for all your thoughts.
Phil
Mr Wizzard wrote:[color=darkred]
> <barry@sme-online.com> wrote in message
> news:1138637760.627653.156710@g14g2000cwa.googlegroups.com...
>
>
> Could be, but I'm not sure there is such a thing as
> "moderate load" in an automobile/light truck; most
> prople put er in gear, and off to jack-rabbit starts
> out of the driveway/stop light on their busy way.
> I think the idea of warming up a car engine no-load
> in the driveway is to let it come up to temp as quick
> as possible while at fast(er) idle so that the corrosive
> byproducts are "on the move" instead of being under
> and load to where pistons are being asked to bear more
> load against the cylinder in this highly corrosive environment
> during cold warmup. Also, the ECM's are dumping mass
> amounts of fuel into the engine during this initial cold-start
> mode making matters worse thus why I would think you'd
> want no-load, high volume air/misture/exhaust air/gas as
> to keep the upper cylinder purged as best as possible while
> the thing heats up to get past this corrosive stage as soon as
> possible. But who knows - I've only seen limited white
> papers on this subject, and actual lab testing results are
> hard to come by on any modern engines. When I say
> "modern", I mean the newer gas car engines where they
> have that new short "land width" of ~3 mm of the top piston
> ring to reduce combuston gas "dead zone". Interesting stuff...
>
>
>
| |
| m Ransley 2006-02-01, 10:21 am |
| philkryder, one thing that may have killed your Honda 1000 hrs early is
running the thicker oil you ran. When oil is cold pressure is highest,
[you need a gauge to measure exactly] Oil filters have Bypass Valves to
Bypass the filter on to high a pressure or restriction, as in clogged.
Cold higher viscosity oil , higher than recommended can on a cold motor
at high rpm open the Bypass alowing dirty oil to pass through to the
engine. Using non Oem filters,and thicker oil can do this. To know you
need to find out the oils pumpimg charicteristics, filter bypass
pressure, and monitor oil pressure. Those statistics are online for
Mobil 1, Generac will have their filter data. The oil data will also
allow you a better comparison to Castrol and Mobil 1. It is also the
easiest way to ruin a car engine, full throttle with a Zero farenhite
temp engine .
| |
| m Ransley 2006-02-01, 12:21 pm |
| Philkryder, I relate the oil issues of cold pumping problems to you
breaking the oil pump shaft on your Honda. You need to research complete
oil specifications.
| |
|
| Cap Group schreef:
> You are taking the "average speed" of the piston, as if it was constant.
It
> is not. The length of the connecting rod will determine the
> acceleration/deceleration rate of the piston. The longer the connecting
rod
> is, the more gradual the acceleration/deceleration rate will be and thus
the
> longer the engine will live (all things being equal).
Acceleration and deceleration on a material will introduce metal fatique.
The frequency of the load on material will introduce metal fatigue much
faster than a static load. The higher the frequency, less time is needed
make the materials break down.
Wear due to frictional forces is depending on the square of the speed the
materials are rubbed against each other. As is the force used to press the
materials against each other.
Slower running engines will not break down due to the lower frequency. The
wear on the piston rings will be about the same (but the pressure/force
lower due to the larger size, so wear will be lower)
> Racing engines
> usually want to have high acceleration rate for the piston, as it helps to
> generate a 'Vacuum under the valve faster to get the air moving( there are
> other combustion issues too!).
More combustion bangs per seconds means more power! That's the main reason.
To keep a limit on the frictional forces of the pistonrings (squared speed
depended) the actual piston speed should be limited. The only way to do
that is not to let the piston travel so much (as with a long stroke engine)
> As such,racing engines will have a short
> connecting rod. Sometimes the rod is so short that the skirt of the piston
> has to be cut away, to allow the counterweights of the crank to pass by
the
The skirt of the piston is there to get a balanced piston, with it weight
just under or on the piston pen, the small end. The connecting rod has an
angle so the force brought to the crankshaft will not be straight down so
the piston could topple around if its centre of mass is above the small
end, and the pistonrings will not glide evenly over the cylinder bore.
Take two strokes, with all those holes in the cylinder...
Secondly: the longer the rod, it becomes more flexible--> must be made
stronger --> more weight --> bad acceleration --> lower revs --> less power
> piston, when it's at the lower edge of the stroke.. Usually the high
hp/wt
> engines have the short rod lengths.
to save weight.
> As the rod length gets longer, the rate of acceleration will get less,
the
only the angle will be less. will not change acceleration.
> instantaneous speed of the piston will go down and wear (and ring flutter)
> will also lessen. Also the 'Torque' of the engine will usually increase.
> There are exceptions, but this basically applies.
That's depending on the crankshaft, greater distance of the big end from the
centre of the crankshaft --> more torque (and a longer stroke of course.
The length of the connecting rod has nothing to do with the torque
> An other factor to a short con rod, is the piston will have a higher side
> load on the thrust side due to the higher angle of the rod during the
> stroke. This will increase the wear on the piston skirt./cyl wall
boundary.
> Conversely, as the rod gets longer, the angle of the push on the piston
will
> get less, and the side load will be reduced, increasing engine life.
> Rule of thumb.. Big and heavy is good for a long time... Small and light
> is good for intermittent use!
> CAP
>
> "philkryder" <alt.google@Kryder.com> wrote in message
> news:1138564875.092887.166240@f14g2000cwb.googlegroups.com...
--
Groet
Ger
| |
| philkryder 2006-02-01, 11:21 pm |
| but don't the diesels - especially the 4 cycle cats have MUCH HIGHER
operating pressure with dual serial turbocharging than a little gas
engine with 8 to 1 compression ratio?
ger wrote:
> Cap Group schreef:
>
> It
> rod
> the
>
> Acceleration and deceleration on a material will introduce metal fatique.
> The frequency of the load on material will introduce metal fatigue much
> faster than a static load. The higher the frequency, less time is needed
> make the materials break down.
> Wear due to frictional forces is depending on the square of the speed the
> materials are rubbed against each other. As is the force used to press the
> materials against each other.
> Slower running engines will not break down due to the lower frequency. The
> wear on the piston rings will be about the same (but the pressure/force
> lower due to the larger size, so wear will be lower)
>
>
> More combustion bangs per seconds means more power! That's the main reason.
> To keep a limit on the frictional forces of the pistonrings (squared speed
> depended) the actual piston speed should be limited. The only way to do
> that is not to let the piston travel so much (as with a long stroke engine)
>
> the
> The skirt of the piston is there to get a balanced piston, with it weight
> just under or on the piston pen, the small end. The connecting rod has an
> angle so the force brought to the crankshaft will not be straight down so
> the piston could topple around if its centre of mass is above the small
> end, and the pistonrings will not glide evenly over the cylinder bore.
>
> Take two strokes, with all those holes in the cylinder...
>
> Secondly: the longer the rod, it becomes more flexible--> must be made
> stronger --> more weight --> bad acceleration --> lower revs --> less power
>
> hp/wt
>
> to save weight.
>
> the
>
> only the angle will be less. will not change acceleration.
>
>
> That's depending on the crankshaft, greater distance of the big end from the
> centre of the crankshaft --> more torque (and a longer stroke of course.
> The length of the connecting rod has nothing to do with the torque
>
> boundary.
> will
>
> --
> Groet
>
> Ger
| |
| philkryder 2006-02-14, 1:21 am |
| The 5-50 castrol gives a wide temperature solution.
We avoid hard start.
And we minimize oil consumption.
We're done with the Hoda's.
The added capacity of the 8000EXL works much better.
And, they are only about one-third the cost.
By, the way, thanks for your data showing that the 7500exl was able to
put out 7000 watts in your resistance tests.
That added a lot of confidence for us.
Phil
m Ransley wrote:
> Philkryder, I relate the oil issues of cold pumping problems to you
> breaking the oil pump shaft on your Honda. You need to research complete
> oil specifications.
| |
|
|
|
|
|
| I've been using a 5kw Kohler (w/Kohler cast iron engine) 3600 rpm
generator (screaming demon) that I purchased new in 1980. It presently
has 2500 hours on it. I installed a magnetic drain plug and it always
has some metal particles on it when I change the oil after every 20
hours of use. I'm sure the magnet plus regular oil changes helps
engine life a lot.
| |
| Bruce in Alaska 2006-02-15, 4:21 pm |
| In article <1139990790.806160.161610@g47g2000cwa.googlegroups.com>,
"philkryder" <alt.google@Kryder.com> wrote:
> er...
> how would that work in an engine with a splash system and no oil
> pressure or oil galleys?
>
PreLube on a splash system, is accomplished by spinning the engine over
multiple times with the Ignition OFF. This is equivilent to cranking
a diesel over with the Injector Pump Rack, held in Cutoff, untill the
Oil Pressure Switch signals Oil Pressure Achieved, and then moving
the Injection Pump Rack to RUN. Most Autostart Diesel engines are wired
this way. This allows the Oil Pump to fill the Filter and Galleys before
the first combustion cycle.
Bruce in alaska
--
add a <2> before @
| |
| Harbin 2006-02-15, 8:21 pm |
|
"philkryder" <alt.google@Kryder.com> wrote in message news:1139990790.806160.161610@g47g2000cwa.googlegroups.com...
> er...
> how would that work in an engine with a splash system and no oil
> pressure or oil galleys?
>
>
> Harbin wrote:
>
Yea, what Bruce said.
| |
| beemerwacker 2006-02-19, 7:21 am |
| You can also increase the life of one of the smaller engines by keeping
it as cool as possible; mechanical fan or (since it's producing power)
electric fan. It's been a few years since I opened up a B&S but I
remember that they used to use an oil slinger to splash the oil about
plus since most were designed to be on a moving platform (i.e.
lawnmower) that also causes oil movement. Since most generators are
stationary, you don't get the additional movement of the oil.
One thing that we used to do to keep the 4 strokers living longer is to
either grab an old oil air cleaner or put a few drops of engine oil in
the fuel for additional lube in the upper end of the engine.
And here's the video you've been waiting for, lube systems in small
engines:
http://www.abbysenior.com/mechanics...Lubrication.MPG
Here's a video about friction inside an engine; explains the metal
bits:
http://www.abbysenior.com/mechanics...%20Friction.MPG
2 stroke lubrication video:
http://www.abbysenior.com/mechanics...on%20System.MPG
Max
http://www.kitcar.dynip.com/solarpower/index.htm
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Harbin