"Dave Butler" wrote in message
...
wrote:
The 100 watt bulb trick is to merely place a drop cord with a 100 watt
bulb inside the cowl while parked and leave it on 24x7. This was first
suggested as a cheap and easy way to preheat, especially if 2 100 watt
bulbs were used. Simply put plugs or rags or such in the cowl openings,
place a blanket or 2 over the cowl, and while not as good as a good
preheater, did keep the engine at a temp above the desired level.
Aviation Consumer did an article on this in the past. They used the
same trick when they were evaluating the dryers, and found that as with
the preheaters, this trick did not perform as well as the devices
designed for that purpose, but did keep moisture out of the crankcase.
They found that this trick kept the air temp inside the crankcase from
5 to 10 deg above the dew point, so no moisture collected on the engine
internals.

I have to wonder whether the moisture evaporated from the above-dew-point
crankcase distills out on the below-dew-point rocker arms and valve
mechanism.

The point of the 100w bulb trick is to keep everything under the cowl
(including the crankcase) a few degrees warmer than the outside environment
to raise the under-cowl temp above the dewpoint.

I don't see any way this technique could hurt.

KB