Fordnatics List Archive

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Mail From: Hans Steiner <(email redacted)>

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I just did a head job and I noticed some strange devices and passageways
that are in my engine and I am wondering WHY? First of all, at the end
of the driver side exhaust manifold, there is a vacuum controlled flap
that cuts off the exhaust flow!! This seems insane to me. But I got a
hunch of why they did it when I was looking at the EGR passages in my
intake manifold. There is a passage that connects two exhaust outlets
from each side of the engine, and runs through this strange chamber on
the underside of the intake manifold that is not sealed from the inner
engine area(i.e. lifter galley). And from there, a passage goes to the EGR
valve. First,
it seems crazy to cut off exhaust flow, and second, it seems even crazier
that it is diverted through a cylinder to the EGR valve. Anyone know
what this stuff is for?

HC
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Mail From: Gordon Laird HP ICBD CDC (415) 857-7247 <(email redacted)>

Hans Steiner inquires:

> there is a vacuum controlled flap of the driver side exhaust manifold

This is called a 'heat valve'. As you noted later, there is a passage
through the intake manifold that connects both sides of the 'V's exhaust.
So, when the engine is cold, exhaust from the driver's side is blocked and
forced to travel through the intake manifold passages, to the other side.
Under WOT, this valve should open, even when the engine is cold. The
passing exhaust heats the intake manifold; thus contributing to the more
efficient evaporization of incoming fuel. Less smog.
As the engine heats, a vacuum port closes, and allows the heat valve to
go to its default state of 'normally open'.

> a passage goes to the EGR

Since exhaust gas is already present in this passage way, of course, its
a simple matter to tap into it for EGR, Exhaust Gas Recirculation.

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Mail From: chucko (Chuck Fry)

Date: Tue, 4 Apr 1995 20:44:05 -0400 (EDT)
From: Hans Steiner <(email redacted)>

I just did a head job and I noticed some strange devices and passageways
that are in my engine and I am wondering WHY? First of all, at the end
of the driver side exhaust manifold, there is a vacuum controlled flap
that cuts off the exhaust flow!! This seems insane to me. But I got a
hunch of why they did it when I was looking at the EGR passages in my
intake manifold. There is a passage that connects two exhaust outlets
from each side of the engine, and runs through this strange chamber on
the underside of the intake manifold that is not sealed from the inner
engine area(i.e. lifter galley). And from there, a passage goes to the EGR
valve.

You may be looking at the heat riser plumbing. Most Detroit iron prior
to the current generation of fuel injection systems used to duct exhaust
gas under the intake manifold and the carburetor to help vaporize fuel
during warm-up. This is the same reason you'll find air ducted into the
air cleaner from the heat stoves on the exhaust manifold.

The valves in both cases are thermostatically controlled (or should be),
so this heat is shut off once the engine has warmed up. The obstruction
should be gone from the exhaust manifold when warm.
-- Chuck

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Mail From: James A Larosa <(email redacted)>


Could be for smog/emissions. My dad had an '86 van with a 460. It
wouldn't pass the smog test so he ripped out the smog device and it would
pass. I'm not suggesting you do the same as I don't know if that's what
your parts are for. I think that US automakers could do away with a lot
of electronic controls on the engine if they would just utilize the full
potential (ie - 1 horsepower per cubic inch).

-----------------------------------------------------------------
> James LaRosa (email redacted) <
> * 1974 F-250 SuperCab <
> * 1989 Schwinn Impact <
-----------------------------------------------------------------

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Mail From: chucko (Chuck Fry)

[Putting on my "average reader" hat here...]

I saw this and I had to write. No offense to the author, but I disagree
with the attitudes represented by this message:

Date: Wed, 5 Apr 1995 09:22:42 -0700 (MST)
From: James A Larosa <(email redacted)>

Could be for smog/emissions. My dad had an '86 van with a 460. It
wouldn't pass the smog test so he ripped out the smog device and it would
pass. I'm not suggesting you do the same as I don't know if that's what
your parts are for. I think that US automakers could do away with a lot
of electronic controls on the engine if they would just utilize the full
potential (ie - 1 horsepower per cubic inch).

I'd love to know what kind of "smog device" could be removed and allow
the engine to run cleaner, and what phase of the test was failed. Do
you have any idea what the problem was? If you try that in California,
the smog Nazis will tell you to put it back on and try again.

Some of the smog devices in the '70s and early '80s were pretty crude,
and did compromise performance without any apparent reason. But to
blindly remove parts and hoses without an idea of what those parts and
hoses do is inviting disaster.

I'd like to counter James' last statement:

I think that US automakers could do away with a lot
of electronic controls on the engine if they would just utilize the full
potential (ie - 1 horsepower per cubic inch).

Just how do you propose to do that without the electronic controls? The
Luddite anti-technology approach might work for NASCAR and NHRA, but it
isn't going to work on the street.

I'll agree that some controls seem redundant. I wonder why anyone
really needs an air bypass valve, for instance. The automakers know
that exhaust gas recirculation (EGR) is troublesome because the valves
clog in cold weather, so computer-controlled EGR is being designed out
of newer cars. It's replaced by "intrinsic" EGR, through tricks like
cam timing that traps some exhaust gas in the cylinder during overlap.

But the modern performance engine would not be possible without
electronic fuel injection and the Lambda oxygen sensor. EFI gives the
precise mixture control required to meet emissions and fuel economy
laws, and the Lambda sensor provides the feedback to keep the mixture on
target. Port fuel injection allows a dry intake manifold, which frees
up the designer to use the long-runner manifold designs so common on
modern cars. This means more torque down low, in contrast to carbureted
performance engines that bogged at low RPMs and only made real torque
above 4K RPM.

So often I hear people lament that the "good old days" of performance
cars are long gone. I'm here to tell you the "good old days" are NOW!
Overall, modern cars are just as fast as all but the fastest muscle
cars, are far safer and more comfortable, handle better, and get much
better gas mileage than the "good old" cars of the '60s. Most
importantly, modern cars pump out far less crud into the air than their
predecessors. What we've lost is underhood simplicity and low prices,
but we've gained enough that I prefer newer cars.
-- Chuck

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Mail From: (email redacted) (K Porter)

Chuck Fry said:
>[Putting on my "average reader" hat here...]
>
>I saw this and I had to write. No offense to the author, but I disagree
>with the attitudes represented by this message:

I disagree with some of what you disagree with .

>So often I hear people lament that the "good old days" of performance
>cars are long gone. I'm here to tell you the "good old days" are NOW!
>Overall, modern cars are just as fast as all but the fastest muscle
>cars, are far safer and more comfortable, handle better, and get much
>better gas mileage than the "good old" cars of the '60s.
The old engines have more potential than the new engines for fun on the
street. New engines just dont have the cubes to get the job done without
screaming (slew of name your "new" v10 motors excluded-they get crap gas
mileage anyway so they violate the better gas mileage statement). I agree
that older cars handle like, well, older cars, and it may really piss off
the pureists but after one soft pedal 4 wheel drum brake 135mph to 0 white
knuckler stop, I put disk brakes on my (then)GTO. That is the whole reason
(to me) behind switching to street rods. Whatever changes I make improve the
value of the machine. I have seen roadsters with indy car suspensions for
example. The same modern technology can be applied to the old blocks and
heads for massive horsepower gains that cannot be matched by modern engines.
How would the 4.6 I hear so much about on this list do against a good old
oil seeping cammer ford big block?
>importantly, modern cars pump out far less crud into the air than their
>predecessors.
Wait a minute! This is the argument used by the scrap'em cretans that want
to crush all old cars. FACT is most of the crud in the air is put there by
newer cars that are poorly maintained. Lookie here->
EPA Mobile Source Report : 85% of the cars on the road have low emmisions as
tested. 7% of the sample generated 1/2 the hydrocarbon emissions and 6% did
1/2 the carbon monoxide. The majority of these cars were post 1980 cars.
Also the Automotive Testing Laboratory showed that pre 1980 cars are NOT
inherently greater polluters than newer post-80 cars. Excessive pollution is
directly related to a lack of maintenance.
Example: I have seen a flat head ford motor with whipple blower, overhead
valves, and electronic fuel injection that made lots of power and burned
very clean (I was told it passed CA tailpipe for current year cars). Fact
is, a smoking car is an embarresment to any performance minded person and
they are going to do what they must to look good. One of the best uses of
that O2 lambda sensor is to use it to balance your multi carb intake! More
and more rodders are doing things like that because they want more from
their engines.
>What we've lost is underhood simplicity and low prices,
>but we've gained enough that I prefer newer cars.
I agree that the technology is good and transfers well to older cars, but
styling on new cars really sucks! I prefer really old cars with some new
technology. Mine may be a little cramped, but it is the only one like it in
the parking lot (I dont even have to get up to look.) I dont see any other
drivers grinning on their way to work every day just because they're driving
their favorite ride! I dont see children making honk your horn signals,
laughing, and waving as you drive by or old people comming up to share a
memory of the "one they had just like it" with owners of this year's model
over at the Walmart parking lot.
yours in rust and real old fashion IRON,
k. "call me Ludlow cause I'm a Luddite" P.
__________________________________________________________________________
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Standard disclaimer area: |with remaining eye!
OFFICIAL DISCLAIMER |
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This read-only message was archived from a public mail list.
Mail From: chucko (Chuck Fry)

Date: Thu, 6 Apr 95 12:42:00 -0500
From: (email redacted) (K Porter)

Chuck Fry said:
>importantly, modern cars pump out far less crud into the air than their
>predecessors.

Wait a minute! This is the argument used by the scrap'em cretans that want
to crush all old cars. FACT is most of the crud in the air is put there by
newer cars that are poorly maintained. Lookie here->
EPA Mobile Source Report : 85% of the cars on the road have low emmisions as
tested. 7% of the sample generated 1/2 the hydrocarbon emissions and 6% did
1/2 the carbon monoxide. The majority of these cars were post 1980 cars.
Also the Automotive Testing Laboratory showed that pre 1980 cars are NOT
inherently greater polluters than newer post-80 cars. Excessive pollution is
directly related to a lack of maintenance.

Point well taken. BUT a marginal late-model car will still put out less
pollution than a well-tuned car from the '60s. And new car emissions
standards are getting tighter all the time. I stand by my statement.

I agree that the technology is good and transfers well to older cars, but
styling on new cars really sucks! I prefer really old cars with some new
technology.

Fair enough. I'd have to agree that not every change on modern cars is
an improvement (when did map lights and power steering become
"mandatory", even on econoboxes?), but a hot-rodder can pick and choose.

Please don't get me wrong. I love to look at old cars, and I have a lot
of respect for the folks who restore and tweak them, but frankly I'm
happier with my late model Mustang than I'd be with an original.
-- Chuck