[Chevelle-list] In case anyone's interested

[Pelle Andersson]

Great work!

Very interesting!

Where can I find the pages you’re referring to?

 

Best Regards

Pelle

 

  _____  

Från: chevelle-list-bounces at chevelles.net
[mailto:chevelle-list-bounces at chevelles.net] För Bill Lessenberry
Skickat: den 24 januari 2007 02:48
Till: Chevelle-list at chevelles.net
Ämne: [Chevelle-list] In case anyone's interested

 

This is kinda like my term paper :-)  Hope you get something out of it.
BillL 

Got Smog??

 
Here’s the result of research that I’ve done pertaining to smog controls on
the 1968~1969 Big Block powered Chevelles.  First, a little legislative
history:
 
In 1955, the Federal Air Pollution Control Act was passed.  This act
provided Federal funding for research about auto emission pollution and
authorized the Secretary of Health, Education, and Welfare to get a better
understanding of the causes and effects of air pollution.
 
In 1959, California was the first state to set standards for air pollution.
These first standards led to the requirement that PCV valves be installed on
cars sold California beginning in 1963.
 
1963 was when the first Federal Clean Air Act was passed.  This act allowed
the Federal gov’t to define air quality criteria based on scientific
research.
 
In 1965, the Motor Vehicle Air Pollution Control Act of 1965 amends the
Clean Air Act.  This directed the Dept of Health, Education, & Welfare to
establish auto emission standards, and provided that these standards be
enforced with the 1968 model year cars.  The Feds used the same standards
that were set by California for the 1966 models.
 
1966 is when tailpipe emission standards were adopted by California, these
standards were used by the Federal gov’t for the 1968 model year cars per
the MVAPC Act of 1965.
 
In 1968, the other 49 states were required to adhere to the California
standards.  Since the auto manufacturers had been installing pollution
control systems on their engines for the California cars, it wasn’t a big
step, manufacturing-wise, to install them on all of the cars.  One of the
systems that was installed was an air-injection system, where a pump
supplied air that was introduced into the exhaust system just outside of the
exhaust port.  The additional air provided ignites the unburned hydrocarbons
in the exhaust, reducing the emissions of the engine.
 
The 1968 standards were carried over into 1969, which is also the year that
the Federal Environmental Protection Agency (EPA) was created.  
Tests conducted in 1968 and 1969 showed that more than half of the cars
built were failing the emission standards.
 
In 1970, the Clean Air Act is amended again to establish a Federal program
to control air pollution.  Part of that program gave the EPA enforcement and
fining powers that it previously didn’t have.  The EPA now had the power to
fine the manufacturers $10,000 per vehicle for non-compliance if they
violated the standards. 
 
 
 Now, a bit of emission technology stuff­
If the perfect amount of air and gasoline are burned in the perfect
environment, the gasoline will break down into H2O, CO2 and CO.
Unfortunately, our cars aren’t perfect and there will be leftover HC that
will be blown out the tailpipe.  The amount of the HC emissions is
controlled by a number of factors, including spark timing, camshaft profile,
carburetor throttle position, and general state of tune of the motor.   In a
manual transmission car, the driver lets off of the gas, shifts gears, gets
on the gas, lets off again, shifts gears, etc.  Each time the driver pushes
on the gas, the accelerator pump squirts, and, unless he’s driving at full
throttle, not all of that gas is burned in the combustion chamber.  The
engineers at the car plants came up with a pump that would inject air into
the exhaust port, the idea being that the extra air would ignite the
unburned HC’s that come out of the motor, thus reducing the emissions.  The
driver of an automatic transmission car doesn’t have to get off and on the
gas when he shifts, so theoretically, an automatic trans car will not create
as much HC pollution as a manual.  Usually, a higher horsepower engine will
have a more radical camshaft profile with more lift and duration.  This
allows for more cylinder filling, i.e. more fuel in the engine.  This fuel
isn’t burned thoroughly in the motor, so it will have more HC pollution than
the lower HP motor and will need more help to meet emission standards.
That’s why higher horsepower or manual transmission Chevelles have the AIR
(Air Injection Reactor) system (aka smog pump) installed on those motors.  
 
REMEMBER:  The Federal standards were applicable to ALL cars produced for
the 1968 model years, whether the states had differing or no standards at
all.  Therefore, it stands to reason that no Chevelles were produced with
the emission controls left off.  I can’t prove it yet, but I believe the
Feds had inspectors at the plants to enforce the rules.

Now you have a little background, so let's get back to our Chevelles.  
Since the 1968 and 1969 regulations were the same, it follows that the '68
and '69 models would have the same smog controls.  If you check the '68 AIM
(and the '69, I don't have one but I hope you do & will research this)
Section 6, Pages A10 and A11, Belt routing,
you will see that the V-8 engine (manual trans) shows the AIR pump, and the
V-8 engine (auto trans) does not.  Page M35, A27 shows the closed style air
cleaner with the heat stove, and also the alternator, water pump, and crank
pulleys without the AIR pump mounting.  Page N40, A7 shows the belt routing
for cars with power steering, also noting that the RPO M35 (Powerglide
trans) doesn't have an AIR pump.  Page M40, A2, has a bunch of statements
under Engine, Fan & Drive, Carburetor, and Air Cleaner that says "Assemblies
same as RPO M35", so that means that the TH 400 had the same equipment as
the Powerglide. 
 
I hope that this has cleared up any questions that you might have had about
the smog equipment on ’68 & ’69 cars.  Flame suit is on!

BillL



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