Re: [T3] "air-cooled theory"

[Steven Ayres <comwest@att.net>]

<x-flowed>WillMcC=> the cooling just seems to take care of itself, practically 
invisibly!

It's all pretty simple.

All cooling air is driven by the fan, which is inside the magnesium fan 
housing. The generator pulley has fins on it that make it look like a 
fan, but it's not -- the fan is forward of that.

The fan draws air from the body via the big rubber 'bellows' in the 
rear. This must be intact to prevent drawing hot air off the exhaust.

The fan housing distributes air for engine and generator cooling and 
cabin heat/defrost.

Two large rectangular openings feed most of the air into the engine tin, 
and it flows over the tops of the cylinders, down through the cylinder 
fins, and out rearward underneath. The oil cooler is on top of the left 
cylinders; you can see the inboard end of it, that's where your oil 
pressure switch is mounted. There's also a set of thermostat-controlled 
warm-up flaps between the fan and the cylinders which open as the motor 
comes up to working temp.

A hole in the top left of the fan housing mates up with a hole in the 
body of the generator, forcing air through the generator and out its 
front and side holes.

The ducts at the top sides of the fan housing direct fresh air to the 
cabin system. The larger ducts go through the heat exchangers (two on 
each side), picking up heat from the exhaust system, and on to a pair of 
mixing boxes mounted on the body behind the rear footwell. A pair of 
smaller ducts with paper hoses run along the heads carrying cool air to 
the mixer boxes. The mixer boxes contain thermostats and flaps that 
regulate the temperature of air flowing into the cabin system so you 
don't melt your tennies. Under the back seat you have a pair of big 
plastic mufflers to quiet the airflow.

On dual-carb systems another paper hose goes from the front of the right 
#1 heat exchanger to the air-cleaner intake as a carb preheater.

That's about it. Check the diagrams in your manual to see the individual 
parts and how they fit together.

Steven Ayres, Prescott AZ
'66 KG1600

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