Trimatic and Emission

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Originally Submitted by T:

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HX/LX or later 6 Cylinder Trimatic Gearbox with Early style Bellhousing. Note the Top Gear Switch (nearside rear of gearbox). Click to Enlargen. Photo by Jason.

Trimatics and Emissions:

Top Gear Switch:

From HX and LX on, Trimatics had a "top-gear switch" fitted to them.

HX/LX or later 6 Cylinder Trimatic Gearbox with Early style Bellhousing. Note the Top Gear Switch (red circle). Click to Enlargen. Photo by Jason.
UC Torana Top Gear Switch. Click to Enlargen. Photo by uca78t.

 

This switch was attached to the kerbside rear of the gearbox and screwed in.
The switch was activated when the gearbox was in top gear.
The wires from the switch connected to a CFS (Cold Feed Switch) and the VAC (Vacuum Advance Control) valve on the engine.
The CFS was screwed into the cylinder head between cyl 2 and 3 in 6 cylinder cars and the VAC
was mounted under the driver's side bolt on the thermostat housing at the front of the engine.
The VAC valve permitted or denied spark advance vacuum between the carburettor and the distributor. Only when the vehicle was up to temperature (determined by the CFS) and in top gear (determined by the Trimatic top gear switch) did the car get vacuum advance.

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