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G.M.
Air Smog System Installation
Smog pump systems were once thrown in the trash, but today
they are in demand to complete restorations. Here’s what it takes
to get that factory finished look.
Perhaps you’ve spent years searching swap meets for
a correct smog pump assembly. Now that you’ve found it what do you
do with it? We have restored many of these units, and we can offer up
some interesting tips about how to refinish and install smog systems.
An internal rebuild can be done professionally or at home, but we suggest
some careful research before you begin the project. One of the most useful
things to have for any Smog Pump project is the correct year shop and
assembly manual. They’re available from a number of tte aftermarket
sources, including HELMS, DRAGICH LIT, ETC Once the unit is mechanically
sound, you’re ready to tackle the cosmetic aspects of the job. Many
of the AIR system components are plated pieces, requiring the services
of a plating professional. The list below indicates the types of plating
finishes required. It’s always a good idea to study the underhood
areas of your type of Smog Pump at shows as long as the car being viewed
as a reference is correct. Take photos of the systems on these cars to
use as reference material. Carefully note the finishes of the various
components. Learn as much as you can before you begin. Ask question. Knowledgeable
enthusiasts are always willing to help. The following example is a 1972
454 engine, but most early GM smog systems are similar. Study your unit
carefully beforehand, noting the finish of each component. Take notes.
You can always use aerosol paint if on a budget instead of plating!..
  Before
Most Air systems are well-worn and heavily weathered, sometimes even damaged.
This 1972 454 unit is missing its diverter outlet assembly.
After
What a difference a restoration makes ! After a complete internal rebuild,
we’ve gone ahead with a cosmetic resto. The system is now ready
to be reinstalled on the 454 engine.
 Note:
Once the components (on the front page) are put back in use on an engine,
In time their factory appearance will deteriorate. We have a simple solution
that has worked for us: a clear urethane finish that acts to preserve
the newly plated/painted surfaces. Here’s the trick: Components
to be urethaned should be suspended with wire in a spray booth or a clean
spray area. Use R-M urethane clear RV 86 and RV87: Mix six ounces of clear
to three ounces of catalyst. Add three ounces of PPG Ditzler DX 685 flattener
to the clear mix. Stir thoroughly and strain into the paint gun (preferably
a gravity-feed type). The temperature should be approximately 75 degrees
with no more than 60% humidity for best results. Hold the gun approximately
12 inches away from the parts, using 50 psi line pressure. Fog a coat
over the entire area of all the components. Let this dry for 10 minutes
and apply one more coat holding the gun only nine inches away at 60 psi.
Let this dry for at least two days before handling with rubber gloves.
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1. We are removing the old block-off plugs where the injection tubes
fit. These plugs were usually placed in exhaust manifolds when a smog
system was not installed at the factory. |
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2. Insert new injection tubes into the manifolds. Push or tap them
very lightly until they seat flush inside the manifold. Note: Remember
to tape or wrap tools where they make contact with nut and bolt heads
to prevent mars or scratches. Or purchase a “no-mar plastic”
socket cover set. Injection tubes are available from most Classic
Car supply houses. |
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