Low engine compression, or is it?

[Kneale Brownson]

At 12:41 PM 06/23/2001 +0100, rob hod wrote:

>. The engine ran ok but was low on compression and
>smoky too. All the signs of terminal bore wear. Under the circumstances -
>i.e. imminent scrapping, I removed the plugs, squirted WD40 into the bores
>and cranked a couple of times, then left a couple of days , then repeated
>the process a second time. Within a couple of weeks normal driving and with
>a few excursions into the 4-5k region the engine had stopped smoking,
>comperssion was back and
>oil consumption down.
>
>     The problem had of course been gummed piston rings, possibly due to
>missed oil changes or the fact that the car never saw more than 1.5k revs,
>or to the dreaded AED enrichment device fitted to those cars.
>
>     The point I'm making is that an engine can give all the indications of
>being knackered when in fact there is nothing *mechanically* wrong with it.
>In particular its always been my experience that general *condition* of
>piston rings/bore is more critical for good running than valve/seat
>condition. I wouldn't know how much of a good idea using wd40 is on an
>engine you intend to keep though.


A little two-cycle oil can have the same result (ie: cleaning up the gummy 
rings).