I also have heard of this trick... Ajax, Vim, Bon-ami... they are all
fine pumice powder.
The theory goes that it breaks down as its ground between the rings and the
cylinder walls, and thus doesn't do any more damage to other areas like seals
or bearings (and you change the oil shortly after...)
Basically, its only a last resort... when you're already resigned to an
engine re-build if it doesn't work, and thus, have nothing to lose...
It IS NOT for old worn out rings, it will never make a worn engine good...
it is for when a re-built engine hasn't run in properly, and is burning so
much oil that you're going to pull it down again... and its an old old
trick, been around since before the 50's I believe?
Anyway... fess-up time... I've done it to the engine in my car!
I rebuilt it, had the bores honed in the way recommended by the ring
manufacturer, and it never ran in properly...still burnt oil 5000km later...
at a rate of about half a litre a week.
So, with nothing to lose, I tried it... it probably did nothing, or maybe
very little, but slowly, over the next 20,000km since the rebuild, oil
consumption is slowly improving... its down to half a litre a month now...
still higher than I'd like, but I can live with it. Was this "improvement"
due to the Ajax, or just more time? I don't know, but it doesn't seem to have
done any harm.
Your mileage may vary...
Its not something I'd recommend whole-heartedly to others, but if you've run
out of options, and are aware of the risks, I'd still try it again...
Fletch.
