[Shotimes] (OT) Marauder

[Ron Nottingham]

OK, so a 6-valve design is inherently better than a 4 or 5-valve design?  I
do not think so.  As the surface area is less due to the design of the valve
itself, resulting in LESS surface area for air flow.  This is not a design
compromise, but physics...

I have also never said that a 2-valve engine is superior to a 4-valve engine
(well, it is in one area, torque production), neither have I stated that a
4-valve engine is superior (one can get more horsepower over a given equal
displacement between engines).  I also never said that engines were 100%
efficient at burning fuel.  As you said, it has more to do with stroke time
vs. burn rate.  An engine at a lower rpm has a longer dwell than at higher
rpm, which makes it more effecient.  Now, what is a factor that makes an
engine have higher emissions is bore size, the larger the bore, the less
effecient the engine is (especially at lower rpm) of burning the fuel, due
to the effect of insufficient swirl and not enough dwell in the chamber to
burn all of the fuel, which is why most big bore engines (I catagorize a big
bore engine as any engine where the bore size is overly large compared to
the stroke) make their power higher up than other engines, say either a
"square" or a long-stroke engine.

OK, you want a 2-valve design that is better than a 4-valve design?  Take
your circle, about the size of a current cylinder bore...  Place anothe
circle in the center of that circle for the spark plug location.  Now, draw
a C-shape on one side, and an inverted C-shape on the other side.  Now, you
are occupying more surface area than any 3+ valve design ever could.  Is
this feasible to use on current engines with current technology?  With
enough money it is.  Is it impossible? No, it's not.

There you have it, 2-valve engines are superior :-)  But, I figure you will
find a way to disprove all of this, so I eagerly await your reply :-)

(I ain't no dummy...)

Ron N. - Dalton, GA
90 SHO

----- Original Message -----
From: "David P" <jpotter8@bellsouth.net>


> The airflow characteristics of 4V heads will always be better than 2V. Why
> would we have 2V if this fact were not true? Mfg's seek profit reduction?
>
> No, motors are not 100% efficient at burning fuel. The engine is burning
the
> same percentage of fuel at it's torque peak as it is most any other rpm.
> What changes is the motor's ability to draw in air and the percentage of
> time spent on the burn cycle (stroke time vs. burn rate).
>
> Quit quoting me cars that are on the market. A mfg's design capabilities
and
> compromise decisions have no bearing on physics.
>
> Try this:
>
> Draw a circle. Draw two circles within this circle, as large as possible
> without passing through each other or the larger circle. Calculate their
> surface area. Now, take the remaining area between these two circles and
the
> outer circle and draw in two circles there under the same rules. Add their
> surface area to the original surface area. Did the total surface area
> increase? Now, obviously head design is not as simple as this, but it does
> figure that you can get more airflow and more even airflow into a head
with
> more valves. I don't care who currently can't or doesn't do it.
>
> David P
>
> 95MTX
>
>
>
> ~
> ----- Original Message -----
> From: "Ron Nottingham" <nottingham@alltel.net>
> To: "David P" <jpotter8@bellsouth.net>; <shotimes@autox.team.net>
> Sent: Monday, November 04, 2002 18:54
> Subject: Re: [Shotimes] (OT) Marauder
>
>
> > How could the cam get more crowded?  You act like a 4-valve head has
never
> > been made for a cam-in-block engine, and that it is impossible.  It has
> been
> > done before, many, many times.  All that is used is a normal V8 camshaft
> > with 16 lobes for the intake and exhaust valves.  Two valves are
operated
> > via one pushrod, and a Y-shaped rocker arm.  Go pick up some back issues
> of
> > Hot Rod or Car Craft, they usually have something in one of them at
least
> > once a year for the past 20+ years.
> >
> > Now, since when did physics change?  Engines have always been most
> efficient
> > at their torque peaks.  Have you ever seen a CVT (Continuously Variable
> > Transmission) in action?  Where does it spend most of it's time?  At the
> > horsepower peak?  Uh, no, they spend most of their time around the
torque
> > peak.  Why?  Because an engine is most efficient there.  Now, to get
this
> > effeciency, would you think the engine is not burning all the fuel it
can?
> > If you go higher, it is burning less of the fuel that is in the air/fuel
> > mixture.
> >
> > The Honda Civic Si is EPA rated at 26mpg city, and 30mpg hwy.   The
> Covette
> > Z06, with more than twice the torque and horsepower, gets 19mpg city and
> > 28mpg hwy.  The new Mustang Mach 1 (complete with 4-valve DOHC engine)
> gets
> > 17mpg city and 25mpg hwy.  What does all this prove?  Absolutely nothing
> :-)
> > BTW, a Corvette with a 4-spd auto still gets 18mpg city, and 26mpg hwy.
> And
> > oh my(!) the Honda S2000 gets only 20mpg city, and 26mpg hwy(!)
> >
> > Oh well, the OHV engine is living on life support (never said it
wasn't),
> > but to discount that 4-valve OHC engines are always better is not
totally
> > true.
> >
> > Ron N. - Dalton, GA
> > 90 SHO
> >
> > ----- Original Message -----
> > From: "David P" <jpotter8@bellsouth.net>
> >
> >
> > > Actually, Ron, it is a slight bit different since a SOHC motor gets
TWO
> > cams
> > > (in any V configuration) while a 4V OHV would ostensibly have only one
> cam
> > > to operate both heads. A 4V OHV motor has to operate three separate
cam
> > > profiles per cylinder spacing vs SOHC operating only two. The cam gets
a
> > bit
> > > more crowded. Sure, they could put two cams into the block, but why
> would
> > > they want to double the drawback of an OHV motor, they valvetrain
> weight?
> > In
> > > case no one has noticed, we are moving away from low-torque passenger
> car
> > > motors (engines, gerbils, whatever) to those that place the torque at
> the
> > > high end of the scale. Gobs of low-end torque means higher emissions
of
> > bad
> > > fumes. To get gobs of air into the cylinder at lower speeds you have
to
> > > restrict airflow turbulence. Turbulence, however, promotes air/fuel
> > mixing.
> > > It's a compromise that takes a lot of time and money to perfect. Look
at
> > the
> > > work that was required to develop the LS1 intake. If the Corvette had
> not
> > > been such a solid seller, and they had not been able to share so much
of
> > the
> > > motor with other high-volume vehicles, they would never have been
given
> > half
> > > the time and money they were to develop the intake system.  Such as it
> is,
> > > they were, and the LS1 and subsequent LS6 are very good OHV motors,
> > however,
> > > they are still near the bottom of ENGINE evolutionary development,
just
> > > above steam-driven pistons. OHC may be costlier, but it has less
> > drivetrain
> > > mass, which will allows for higher revolutions, which allows for more
> > > efficient engines. SOHC and DOHC are replacing OHV designs as we talk
> > about
> > > it, so it's not really an issue of will this occur, as much as a
> question
> > of
> > > when will you no longer be able to find an OHV motor in a passenger
car.
> > > You've got to meet EPA guidelines if you want to avoid being fined out
> of
> > > existence. What is Chevy going to do with the Corvette when the stakes
> are
> > > raised to 50mpg? Put in 2.53 gears? What about 75mpg? 100?
> > >
> > >
> > >
> > >
> > > David P
> > >
> > > 95MTX
> > >
> > >
> > >
> > > ~
> > > ----- Original Message -----
> > > From: "Ron Nottingham" <nottingham@alltel.net>
> > > To: <shotimes@autox.team.net>
> > > Sent: Monday, November 04, 2002 09:22
> > > Subject: Re: [Shotimes] (OT) Marauder
> > >
> > >
> > > > I, for one, would like to see "plenty of 4-valve OHV" engines (the
> > correct
> > > > term, since a motor is electric :-).  I do not know of any
production
> > > > pushrod 4-valvers.  Although I have seen many different designs for
> > them.
> > > > No different than, say, a SOHC 4-valve engine, and there are plenty
of
> > > those
> > > > around, as Honda is a HUGE manufacturer of SOHC 4-valve auto
engines.
> > > Most
> > > > Civics and Accords only came with 1 cam :-)
> > > >
> > > > Ron N. - Dalton, GA
> > > > 90 SHO
> > > >
> > > > ----- Original Message -----
> > > > From: "Midwest SHO Specialists SHOtimes"
> > > <MidwestSHOspecialists@hotmail.com>
> > > >
> > > >
> > > > >      Actually there are plenty of of 4 valve OHV motors around.
You
> > do
> > > > not
> > > > > need to squeeze extra lobes on the cam either.  All of the pushrod
> OHV
> > 4
> > > > > valve engines that I have seen have fingers in the heads that
> operate
> > > both
> > > > > intake valves off of one pushrod.  This is very similar to how
SOHC
> > 16V
> > > 4
> > > > > bangers operate.
> > > > >
> > > > >      Also Yamaha didn't have the advances that we have now when
they
> > > were
> > > > > designing this motor.  Keep in mind that the motor was designed 17
> > years
> > > > > ago!  That's amazing when you think about it.  They were waaaaay
> ahead
> > > of
> > > > > their time.  I digress though.  Hydraulic tappets were not used
for
> > fear
> > > > of
> > > > > high RPM oil foaming which would have caused them to collapse.
> > > > >
> > > > > ~ Mike
> > > > > ----- Original Message -----
> > > > > From: "David P" <jpotter8@bellsouth.net>
> > > > >
> > > > > > Since all OHV motors are two-valvers, and four valves allow more
> > > > efficient
> > > > > > combustions, then pushrods DO have a bit to do with emissions,
at
> > > least
> > > > > > until they figure out a way to cram 4V onto a single cam. Sure,
> > > injector
> > > > > > placement, intake flow, etc play a large part, but when
> considering
> > > > solely
> > > > > > 2V vs. 4V, 4V is going to win on emissions and power. You think
> > maybe
> > > > > there
> > > > > > is another reason why the Corvette runs a 2.73 final?
> > > > > >
> > > > > > As for OHC being high maintenance, I think you are forgetting
that
> > the
> > > > SHO
> > > > > > does not have a hydraulic tappet. Remove the hydraulic tappet
from
> > any
> > > > OHV
> > > > > > motor and it becomes just as maintenance intense. Not as
expensive
> > to
> > > > > build,
> > > > > > but just as expensive to maintain. If Yamaha had inserted
> hydraulic
> > > > > tappets
> > > > > > into their design, we would not be sitting here exclaiming the
> need
> > to
> > > > do
> > > > > > the 60k on time.
> > > > > >
> > > > > > Sure, the small block (or more specifically, the OHV design)
will
> be
> > > > > around
> > > > > > for some time, but eventually it will be dropped in lieu of more
> > > > efficient
> > > > > > designs in our nation's quest for emissions reduction. Don't get
> > upset
> > > > > about
> > > > > > it though, as OHC's days are numbered as well. There are much
> better
> > > > > > air/fuel injections systems on the boards and in testing that
> don't
> > > have
> > > > > > valves as we conceive them that will see fruition in the last
half
> > of
> > > > this
> > > > > > century, leaving OHV as the predominant valve design of the
19th,
> > 20th
> > > > and
> > > > > > 21st centuries. Not too bad a run, but definitely a technology
> that
> > > has
> > > > > > outlived it's usefulness.
> > > > > >
> > > > > > ----- Original Message -----
> > > > > > From: "Donald Mallinson" <dmall@mwonline.net>
> > > > > >
> > > > > > > Yes production was low, although that is what you said, not
> > > > > > > i.  They also sold every one they made, and even ramped up
> > > > > > > production and held it longer than planned to try to meet
> > > > > > > demand.  You expected maybe they would sell them in Focus of
> > > > > > > Camry numbers?  NO special vehicle sells in big numbers,
> > > > > > > Cobra, RX7 etc.  But they did sell a lot of the basic
> > > > > > > Caprice, a great tow vehicle and very good police car that
> > > > > > > the police across the nation still lament not being able to
> > > > > > > get.  They have never warmed up to the low torque and low HP
> > > > > > > "High tech" Crown Vic.
> > > > > > >
> > > > > > > High emissions?  Not really, the small block chevy lives on
> > > > > > > in the Vette and a huge amount of other applications as a
> > > > > > > low emissions vehicle!   And don't spout the "low tech"
> > > > > > > pushrod cam mantra.  The motor works and puts out more HP
> > > > > > > and torque than competing motors from Ford.  Pushrods have
> > > > > > > nothing to do with emissions, it is ignition and fuel
> > > > > > > control more than anything, and combustion chamber design.
> > > > > > > The new small blocks are as good as anything out there,
> > > > > > > better than most.
> > > > > > >
> > > > > > > I am a basic fan of Ford, but there is NO, repeat, NO
> > > > > > > arguing with the extreme success of the small block Chevy.
> > > > > > > Ford had a similar motor, but they dumped it.  Now they are
> > > > > > > really struggling with the more expensive to make and
> > > > > > > maintain OHC motors.
> > > > > > >
> > > > > > > And yes, mods are plentiful, they work, and are cheap.  That
> > > > > > > , my friend is the outline and model for the most successful
> > > > > > > motor of all time, including today.  I am willing to bet the
> > > > > > > small block is around longer than the OHC Ford motor.
> > > > > > >
> > > > > > > > ----- Original Message -----
> > > > > > > > From: "Donald Mallinson" <dmall@mwonline.net>
> > > > > > > >
> > > > > > > >>I agree with much of what you say, but you imply that the
> > > > > > > >>Impala from the mid 90's was not successful.  Nothing could
> > > > > > > >>be farther from the truth.  That car sold above sticker for
> > > > > > > >>its entire run, and was only killed when GM needed the plant
> > > > > > > >>to build more prolific and profitable trucks/suv's.
> > > > > > > >>
> > > > > > > >>
> > > > > > > > Well, I was looking at production nos. awhile ago, and they
> were
> > > > low.
> > > > > > So
> > > > > > > > what you are saying is that GM kept production low?  That
> would
> > > > > explain
> > > > > > low
> > > > > > > > sales and remaining residual demand.  Of course the mods
will
> be
> > > > > > plentiful
> > > > > > > > for that engine, but its old tech, high emissions design
dooms
> > it.
> > > > _______________________________________________
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