Subject: bedding in rings

[RonHorowitz <RonHorowitz@xxxxxxxxxxxxxx>]

Hi, ronewing!

> breaking in
>stubborn piston rings using something like scouring powder.

Bon Ami, but I wouldn't recommend it.

> Is this a legitimate
>technique?

I'd call it an illegitimate technique, toe-may-toe, toe-mah-toe....

First, the general disclaimer. If it's possible the problem has been
mis-diagnosed, it's possible the right fix for the wrong diagnosis won't
help. Are you _sure_ the rings aren't sealing? Why? Dry compression? Leak
down? Blow by? Oil consumption? You're certain the rings were fit right
side up and with the right end-gaps in the bores? Rings weren't bent or
twisted on installation? Lands are sealing OK? Sure it's not the valves,
seats, cam timing, etc? Not trying to be difficult, just have to ask.

>I'm trying to help out a friend with a fresh engine on an old
>BMW where the machinest used too fine a stone for chrome rings, which just
>refuse to seat.

Assuming it's the surface finish on the walls, and assuming it's because
the machinist used the wrong stones, can you fit moly rings?

>Short of pulling and tearing down the engine again this
>seems appealing if it would work.

I suspect it only appeals because it's easy. It's unappealing if it doesn't
work, which it may not. Even if the finish on the walls is wrong, and even
if Bon Ami sort-of "fixes" the rings, it won't do anything good for
anything else. If the rest is right, I'd advise to fix what's wrong rather
than gamble on two wrongs to raise the average.

>IIRC, you pour a small amount down the
>throat of the carb and let it run for a while, then change the oil, flush
>the engine, etc.  Anybody?

You're talking about pouring abrasives straight into a running motor. If
you're cool with that, go right ahead, but I wouldn't want do it.

Hope you find my advise useful.

RON
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