Thread: S III 2.25 1976 Anti-pollution gear

I'm no expert but my understanding is that these two anti-pollution systems are the only ones that do NOT hurt your fuel economy or power.

The PCV system consists of a pipe from the oil filler to the PCV valve next to the carburettor, with a rubber elbow from there to the adapter below the carburettor, and a hose from the top of the rocker cover vent to the elbow in the air intake above the carburettor.

Unless the valve is faulty (stuck or split diaphragm) removing this will have no effect whatever on performance, but unless complete crankcase ventilation is changed to a proper open crankcase ventilation system, the engine is likely to be damaged by sludge buildup, depending on use and climate.

The fuel tank vapour trap will also make no difference to performance unless it is blocked. Removing it will make no difference except to render the vehicle technically unroadworthy, provided fuel tank ventilation is still provided.

John

Thanks John, That's what I thought was the case. I suspect my mate is thinking of other systems such as the throttle valve opening system (on over-run)which was installed on some vehicles at around this time, which probably do have a slight impact on fuel consumption.

Coop

He may have been thinking of something else.

He may have done at the same time some other adjustments or maintenance that really did affect fuel consumption.

He may just be one of those people who is able to convince themselves that the vehicle goes faster just because they:

• Blackened the tyres
• Cleaned the windscreen
• Painted the vehicle red
• Fitted a Hiclone

Given the simplicity of the Series III emissions fittings, it's hard to imagine anyone thinking they would make a big difference.

Yes. I'm not sure what was on later Series 3, but I think they included a fuel shutoff on overrun, different distributor, and sealed mixture and idling control screws. These did affect consumption, driveability and power, but are not all that easy to disconnect.

John

My workshop manual also describes an air pump, although I've never seen one fitted. Were they used in Australia?

Coop

They were used on the V8, although I am not sure that applied to the Series 3/110 in Australia, maybe only the Rangerover due to the detuning of the S3 and perhaps different vehicle classification.

John

Originally Posted by vnx205

........

Given the simplicity of the Series III emissions fittings, it's hard to imagine anyone thinking they would make a big difference.

The PCV in particular has the potential to result in poor running, but only if faulty. I've had this myself - split diaphragm, but any vacuum leak could do it. Of course, the solution is to fix it not remove it, especially for this, as it improves engine life by providing good crankcase ventilation without letting in dust.

John