Compression loss - what happenned?

Not really, no. More likely all the oils drained out of the hydraulic lifters.

Could it be "bore wash"? The engine gets flooded, and the fuel washes the oil off the rings, so they don't seal properly. The suggested solution is to remove the plugs, put a small amount of engine oil directly into each cylinder, clean the plugs up of course, put them back and try again.

You can hear compression? Why Granddad what big ears you have!!

I wondered what that was too! :)

"Duncan Wood" wrote in news:op.tnu5cyrqyuobwl@lucy:

That was my thought too.

Paul Andrews has brought this to us :

You cannot hear the compression. You can hear it cranking faster than normal, or if you turned the engine over by hand you might hear the compression leaking away on the compression strokes, but not the compression or lack of while it is cranking at normal speeds.

what I meant was that I could hear the starter motor turning faster than usual, without the normal speed (and hence sound) variations caused by the extra load on the starter motor due to compression strokes. Does that make any sense of my original post, or are people just being pedantic?

Paul.

Just trying to be clear on what you actually meant.

Have you checked the cam belt and confirmed it is going round?

Well unless it's a self healing belt, I presume it's OK. The OP stated the car has been fine since.

I bet you could hear it if you put your ear to the exhaust.

(do not put your ear to the exhaust)

No?

So, you _can_ hear (an effect of) loss of compression.

Is this a strange philisophical discussion about what "compression" sounds like?

It's really quite simple: an engine which for some reason has lost compression will sound different to one which hasn't. You CAN hear it.

After serious thinking David Taylor wrote (and still got it wrong):

Not quite. You can hear the effects or symptoms of the compression, rather than the actual compression - simple really. Take the plugs out or the exhaust manifold off and you will then hear the actual whoosh noise of the compression.

The idea of the original questioning of the 'hearing of the compression' was to simply help work out a little more of the problem.

Is that the actual whoosh noise of the compression? With no plugs, there is no compression, only a whooshing sound as the air that would have been compressed is blown out of the plug holes.

In other words, what you are hearing is no more than a mere indirect epiphenomenon of compression, not the actual compression itself.

Ben C explained on 19/02/2007 :

If there were no compression, then there could not be any movement of the air. The reason why it moves is that there is a difference in pressure, the whoosh resolves that difference.

If you can't hear air being compressed then you're deaf :-) & if it's not compressed it won't blow out the plug hole.

But then, everything you can hear is a soundwave, or air being compressed....