Non-SE-R: GM OHV engines

Jack Ray rjrjack@knology.net
Tue, 3 Dec 2002 00:23:17 -0600


If you get this twice, well, you don't have to read it twice (or even once
:^)

Rick wrote:
> One of the more knowledgeable should correct me if my diet is potassium
rich.

> I have always been told that one of the major advantages of 4 valve heads
> lies with the pentroof (5 sided) combustion chamber configuration.  Having
> more, smaller valves allows much more flexibility in designing the
> combustion chamber shape.  Proper design allows running higher compression
> w/o detonation, all other factors held constant.  I guess this would be
> true regardless if a cam or rocker arm opens the valves, but how many DOHC
> engines have less than 4 valves/cylinder these days and how many rocker
> armed motors run 4 valves/cylinder?

When you're right, you're right.

> Enough of GM engineer bashing.  I realize rocker armed motors in a vette
> these days seems archaic but GM is moving on.  My wife drives a GMC with
> the vortec 4200 inline six.  This is a 4.2L inline 6 w/ DOHC and 24
> valves.  To me, this thing is a marvel.  It is silky smooth, quiet, <snip>

Inline 6 cylinders are sweet.  4.2 Litre inline 6 w/DOHC, sounds like the
Jaguar engine they put in (among other things) the XKE.  Inline 6's have
perfect primary balance.  Are you aware that Pontiac built an OHC 6 in
the 60's ?  Put it in a Tempest. 0 to 60 in around 10 seconds.  Another
good one is the Chrysler slant 6.  One of the toughest engines ever made.
Originally designed for aluminum block, then they poured those same
generous proportions in cast iron when they had problems w/volume
production of aluminum blocks.  So, in iron, it was WAY overbuilt.

Ain't nothing wrong with GM's V8's.  Ain't nothing wrong with OHV engines.
What's important is do they put out good power for the fuel they consume.
And a good V8 winding out sounds at least as good if not better than a
high-winding 4 cylinder.

> My current dream car:   A pontiac solstice coupe w/ a vortec 4200 stuffed
> in it.  Turboed of course.

I'd like to have a mid-60's Plymouth, modernized with fuel injection,
6-speed, disc brakes all around, electronic ignition, blablablah.....

> Since that car doesn't yet exist (holding out hope), then I'd consider a
C5
> corvette w/ an inline 6 transplant.

If it has to be a 'Vette, then get a Lingfelter (sp?) V8 in it - the 4.2
liter six would be handicapped by it's relatively small size (compared
to standard V8).  Save the sweet six for a lighter car, one that's more
of a sleeper.  IMHO, of course.

I'm kinda turned off about Corvettes nowadays, because GM, to beat the
Vipers at LeMans, created a pure race car, gave it a skin that looked like
a Corvette (shades of NASCRAP), and then got all this publicity about
how Corvettes beat the Vipers at LeMans.  What a joke.  Yes, Corvettes
are actually nicer cars to live with than Vipers, but they sure as hell
ain't
faster (smile)...

> I am a die hard GM fan, although I can easily look to imports for
> performance,

GM doesn't do anything for me.  But then, neither does Chrysler or Ford.
Not these days.

<Mounts soapbox>
      When all the gas is gone, it's gone.  People have no idea how much we
depend on oil for our way of life.  It's the source of plastics, gasoline,
lubricants, heat for our homes, and a major fuel for electricity generation.
It's hard for me to be excited about companies that do such a vigorous job
of promoting the sale of 12 mpg pigmobiles, and truly don't give a rat's
ass about the harm their products are doing the world.  They just make a
few pretend efforts to improve gas mileage, to appear socially conscious.
Life's gonna be much harder all over the world when the oil's gone, and
America is the biggest pig at the trough.  By far.
      It's hard to get mad at the true source of the problem, which is the
people who buy those pigmobiles.  A lot of them are really nice people.
It's just, I guess this is it, that gas has always been available at the gas
station, just there like the sun and rain, and people just don't think about
it running out.  And, yes, I know, some people actually need the
functionality of an SUV.  But, hey, a Cadillac SUV ?  Pathetic..
<Gets down from soapbox>

Jack (have a nice day) Ray
94 SE-R