Are you sure that yo can blow/suck through the gauge hose with it not
screwed into the spark plug hole? Most gauges have a check valve in the
end to keep pressure on the gauge when compression pressure drops off.
It doesn't happen too often, but I was asked to do a tuneup on an old VW
bus and found 0 compression on 1 cylinder. The piston was broken at the
top ring groove. Turns out the owner had been driving it that way for
almost a year. He had been in heavy traffic on vacation, heard a bang,
and power dropped off. After he got out of traffic he forgot about it
until I found it. Since the VW is a horizontal cylinder, the top of the
piston would vibrate a bit out of position, then the rest of the piston
would come up and smack it back into place. There was a fair amount of
deformed metal on the broken edge of the piston crown from being nudged
back into place for most of a year!
Mr. McDougall wrote:
>ok, yes I have bad news for me but I would like to
>understand just how bad, maybe?
>my number 1 cyl is just not generating any
>compression, yet when I blow into the hole with the
>compression hose , it resists completle, I also cant
>seem to suck any air through the hose. I have checked
>and even compared the valve clearances and I can see
>the valve stems moving up and down when I crank it
>over. The only thing I can think of is that the
>piston isn't moving (yikes)? Anything else?
>PS I know I am a pain, but I would like to join the
>running roadster club someday.