Guys, I read this on rec.autos.antique. I thought it was pretty
nifty for changing the valve springs, etc. with the heads still
on the car. No engine pull!

>Tony Day (tday@netcom.com) wrote:
>: I have heard that it is possible to change valve stem seals without
>: taking the heads off, by applying compressed air through the spark plug
>: hole with a special adaptor. What power of compressor is needed? I have
>: seen 12V compressors advertised (JC Whitney) for <$50 which claim
>: 260psi and 3.5min. to inflate a tyre.  Would these do? 
>
>If you can turn the engine over by hand (via the fan or belt/pulley,
>both forward and backward), you don't need a compressor.  Just feed
>several feet of clean rope into the cylinder via the spark plug hole
>and hand turn the engine over so the piston crushes the rope up 
>against the valves a bit.  Now the valve won't drop into the cyl-
>inder and you can change the stem seals.  Of course, you can't knurl
>the guides, but that's probably OK too...   when done, crank the
>engine back to loosen the rope and pull it out ("You mean you pushed
>it ALL in?  Um... got any tweezers...?")
>

It should work, especially if you use non-plastic rope. But keep it
clean and make sure you have the cylinder at TDC for that jug.

--- Chris Chubb (cchubb@ida.org)
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