TQ Factory Metering Rods and Jets
Factory metering rods are all numbered, but the problem is we know of no reference that lists the rod sizes. We have archived a list of the factory rods per the final blueprint specs from Carter Automotive Company. The specs compiled here provide the first comprehensive reference that we know of. These specs give the rod diameter at a glance, to make rod selection and tuning easier. A fatter rod plugs up more of the jet, reducing cross-sectional area, and thus fuel flow. Most TQ rods have three steps: economy, in action when under light throttle cruise; mid, under higher load or throttle opening; and power, high load and WOT. Remember, as soon as the throttle is snapped to wide open, the rod will instantly be up on the power step, no matter the rpm. Primary jets are also numbered, but last three digits of the number relates to the orifice size directly. For instance, a primary jet 4095 is .095-inch or a 4101 measures .101-inch. Similarly, the last three digits of a secondary jet equates to the size as a fraction of an inch. A 5110 jet measures .110-inch, while a 5143 measures .143-inch.
After cleaning (a soak in...
After cleaning (a soak in a tub of old-style carb cleaner is best), the subassemblies are reloaded with their respective parts for final assembly.
Do not forget to install the...
Do not forget to install the O-rings or the carb will be horribly rich, and the car will be undriveable.
Some emissions TQs seal and...
Some emissions TQs seal and vent the bowls solely through this solenoid valve at the rear. Unless wired-up and energized, the bowl will not vent properly, creating a fuel-starvation condition. Leaving off the rubber seal will allow the carb to vent normally, even with a failed or disconnected solenoid, but defeats the emissions intent of the device.
On '75-and-newer passenger...
On '75-and-newer passenger car TQs, we find a flat boss at the front of the air horn, which may or may not have various holes drilled into it, often with confusing devices attached. Here's the deal: these carbs were equipped with an auxiliary air bleed circuit, and the devices at the front open and close this air bleed to the atmosphere. When open, the signal to the primary main jets is weakened, leaning the mixture. The setup normally runs open, and is controlled by vacuum to the closed (rich) position during cold start-up. Besides the vacuum control, some carbs carried a barrel-shaped bellows (shown here), which varied the opening in relation to air density, to compensate for altitude changes. A common TQ mod, the control valve can be blocked by replacing it with a fabricated plate (shown in the left foreground). Removing the control mechanism and blocking the air bleed results in the carb running at the rich setting full time. As we will see, this is not always the best way to go.
For a rolling test bed, James...
For a rolling test bed, James Schagel volunteered his 360-powered '75 Duster. The stock short-block 360 is fitted with an MP .455-inch lift camshaft, 360 smog heads upgraded with 2.02-inch intake valves, a Weiand two-plane intake, and stock exhaust manifolds blowing into a 2 1/2-inch system. It's a mildly modified street 360, which we felt typified a large group of street enthusiast's combinations.
Using a TD adapter, the TQ...
Using a TD adapter, the TQ was mounted to James' 360. Call us odd, but the TQ carb just looked right on that small-block Mopar.