On Dec 30 2007, 7:15 pm, "NotMe" > wrote:
> "Veeduber" > wrote in message

> My grand father had an adaptor for the Model T that would provide compressed
> air by removing one of the spark plugs. Only draw back the air had a lot of
> gas fumes.
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The typical 'spark plug' compressor was a captive, spring-loaded
piston in a brass cylinder that screwed in to the spark plug hole. The
engine's compression stroke powered the device to pump ambient air,
not the charge from the cylinder. The instructions said to give it a
drop of oil before screwing it into place but little if any of that
oil found its way into the output.

I've heard several people say the things used air from the engine so
there may have been some that simply diverted the fuel/air charge into
a tire, but none of the ones I've ever seen or used worked like that.
And they DO work rather well. Displacement was typically one cubic
inch so the output was about .25cfm at an idle (ie, about 400 strokes
per minute). Pressure depended on the compression ratio & condition
of the engine -- you wouldn't get much from a Model T but then its
tires didn't need very much. On a 1953 Mercury flat-head V8 you'd see
better than 120psi and most VW's could do 75 to 90 psi.

-Bob Hoover