General Information on the '71 429
Mustang and Cougar Emission Systems (by J.
429 CJ cars had what Ford called the
IMCO system, for IMproved COmbustion. It consisted of modifications to
ignition timing and fuel mixture. Things that accomplished this included
the Q-jet carburetor, the dual diaphragm distributor, and a throttle
solenoid which helped to prevent over run on shut off. Another device
(often missing today) is a thermostatic switch atop the vacuum
distributor fitting (on the thermostat housing) which served to advance
the timing (thus boosting engine speed) when the engine heated up during
prolonged idle. CJ cars did not use the Thermactor (air injection)
429 SCJ cars are more interesting. All of the original ones I have seen
were equipped with the Thermactor system, similar to the that on 428 CJ
and Boss 429. The biggest difference is the air injection is routed to
the back of the cylinder heads on the 429, as opposed to the individual
exhaust port areas on the FE engines. I have been told the less precise
fuel mixture control of the Holley mandated the air injection to keep
emissions under control (It is also said Ford's desire to get away from
Thermactor is why they went with the Q-Jet on the CJ. They had to go
with the Q-Jet because their own big smog carburetor, the 4300D, wasn't
ready when the 429 CJ went into production. The 4300D finally appeared
on the 429, but not until 1972 as the 429 Police Interceptor. Both it
and the 4300D Boss 351 of 1971 and 351 CJ and HO of 1972 avoided air
(Note: Click thumbnails to enlarge pictures.)
Complete Thermactor System
The complete Mustang/Cougar/Torino
SCJ smog system was taken from the 70 -71 460 Lincoln
line, except for the pump pulley, which is a unique 70
T-Bird part. The pulley may have been left over parts stock,
since "smog" wasn't available for the 70-71 429
T-Bird. This would make the SCJ smog pulley quite rare today. An
assembled 429 SCJ Mustang system is shown above and all of the
individual components are below. Note the very rare D0SE
pulley in the photo below right.
Smog Pump Pulley
by Dan Davis
The D0OE pulley
was used on all California emissions 429/460 engines.
These engines were found in Lincolns, T-Birds, Galaxies,
Marquis', etc. Oddly enough, the 429SCJ engines used an entirely
different pulley numbered D0SE. The difference is in the offset,
with the D0SE pulley having near zero offset and the D0OE pulley
having 3/4" or so. Yup, the engineering numbers seem backward,
but that's the scoop.
Since the D0SE pulley was ONLY used on SCJs, it is one of the
most difficult parts to find for our cars!!!
What can you do? I would source a water pump pulley from one of
those Calif. emissions engines. You can then put a belt on the
pump and only hardcore geeks such as myself would know it's not
"correct." This water pump pulley is dimensionally identical to
the CJ pulley, but has a provision for the small smog pump belt
between the alt & PS pump belts. That one should be fairly easy
to find amongst the Lincoln/T-Bird crowd.
Photos Below are of the D0SE Pulley
(Thanks to Jerry Ostalecki for providing)
View of System Installed
The photos above are of the Smog
system on Fred Coyner's low mileage all original 429 SCJ
Mustang. The smog pump pulley was stamped D0SE-9C480-A, and had
a 5 1/2" diameter with a 15/32" sheave.
|Details on Smog
SMOG (Thermactor) Pump
Here is the 68-71 Thermactor
pump (C8AZ-9A486-C) used on the 429 SCJ Mustang. This pump
featured a round pressure relief valve in it's side. The color
of the valve was blue with a gold cad frame. The pump itself was
bare aluminum, with an aluminum 90 degree hose nipple. The pump
also had a semi-black cast iron rear housing with silver
hardware. The pump used a white centrifugal filter fan in the
front, and the pump's shaft end was painted yellow. If you're
looking for a Smog pump, note that pumps from the mid 70's will
work, but they didn't contain the pressure relief valve. The
correct white pump fan is shown below.
The photo above left shows the
smog belt adjustment bracket (long one) which was marked
D0VE-9B452- A. Just below this is the small triangular bracket
(marked D0VE 9C486 A) that held the by-pass/diverter valve to
the belt adjustment bracket. This triangular valve bracket,
along with the 2" round clamp was only used on cars built
before 3/1/71. The SCJ water pump pulley, which was the same as
the CJ w/ PS w/o A/C, was marked D0OE-8509-M. To the left
of the pulley is the alternator bracket. The pumps mounting bolt
was 6" long, and the pumps spacer was 1 13/16" in
length (photo at right).
Smog Pump Mounting/Alternator Bracket
The 429 SCJ uses a modified
429 CJ alternator bracket to mount the Smog Pump to the engine.
As can be seen in the photos above, Ford added an additional
mounting tab to the CJ bracket to serve as the lower mount for
the Smog Pump. This mounting tab can be clearly seen in the
photo at center right with the CJ bracket overlaid on top of the
SCJ bracket. The SCJ bracket is part number D0VE-9B450-A as
shown in the photo at top right and bracket alone is shown
Below is a view of this
bracket installed (without smog pump) showing the eyelet that
provided the lower mounting point for the smog pump.
Smog Belt Adjustment
The pictures above show two
angles of the D0VE-9B452-A smog pump belt adjusting bracket. The
red arrow shows the installation location of the D1VE-9C486-AA
by-pass valve mounting bracket.
Below is a view before and
after installation of
the D0VE-9B452-A smog pump belt adjusting bracket.
Here you can see the air
by-pass/diverter valve with it's cover in place. The cover was
stamped C8TE-9B289-B, and also was stamped with the valve's
build date. Normally, the pumps output air flowed to the
cylinder heads exhaust ports whenever the engine was running.
What this did was inject fresh oxygen into the hot exhaust gas,
and this caused any remaining unburned fuel to be re-ignited in
the exhaust port and be reburned to lower the exhaust emission
level. Now, during times of engine deceleration, the pump's air
flow was diverted for 3 seconds from the cylinder heads, and
sent to the 2 oval exit slots in the by-pass valve's cover. The
cover also acted as a muffler for this by-passed air. The
by-pass of the pump's air from the exhaust ports was done to
prevent exhaust backfiring during engine deceleration when the
engine's air/fuel mixture would go slightly too rich. You will
sometimes see the by-pass valve called an "anti-backfire
valve". The Pump to Diverter Valve Hose
and correct attaching clamps are shown at loer right. This
short "S" hose was 8 3/4" long, and was stamped
Valve Mounting Brackets
There were two different
mounting schemes for these Bypass/Diverter Valve. These are
Bypass Valve Bracket used from 8/70 thru
The triangular bracket shown
above left is the by-pass valve mounting bracket that was used
on cars built from 8/70 thru 2/71. It's part number is
by-pass valve mounting bracket mounted to the D0VE-9B452-A smog
pump belt adjusting bracket (above center and right).
As shown below, the by-pass valve is placed
in the curved saddle formed by the D0VE-9C486-A
mounting bracket and a clamp goes around the by-pass valve
housing and tightens against the curved underside of the
mounting bracket. An installed view is shown below right.
Bypass Valve Bracket Change on 3/1/71
The diagram above shows the
by-pass valve mounting bracket that was used on cars built from
3/1/71 on. The bracket switched from the triangular D0VE-9C486-A
to the D1VE-9C486-AA shown in the photos above on 3/1/71.
The photos below show
the D1VE-9C486-AA by-pass valve bracket mounted to the end of
the D0VE-9B452-A the smog belt adjustment bracket..
The photos below show how the curved surface
of the D1VE-9C486-AA
bracket clamps to the hose (Smog Pump to by-pass valve).
A final installation view of By-Pass Valve on
the 3/1/71 level bracket is shown below. Note that the By-Pass
Valve is clocked so the rear of the canister is pointing at 1:00
(instead of 12:00 on the pre 3/1/71 design). This clocking of
the valve was necessary to gain clearance between the support
bracket and the nipple on the bottom of the canister. This angle
change is also shown in the MPC diagram at lower right.
Emissions Recovery - Charcoal Canister
The charcoal canister was
found on bothe the 429 CJ and SCJ applications.
This is the charcoal canister. It was mounted
in the engine compartment (rear of passenger side as shown
above) to the inner fender apron with a bracket. The inlet side
(small fitting) hooked up to a tube from the fuel tank. The
outlet side (larger tube) ran to a fitting on the air cleaner
(with a filter element). When the engine was running, it served
as a system to aspirate and burn excess gasoline fumes to
prevent the fumes from escaping to the atmosphere. Additional
photos of the canister and it's attachment bracket are shown
below as well as an original showing factory hoses and clamps.
Wong's 429 CJ Grande