valve job question

[William T Wilson]

On Sun, 2 May 1999, Stowe, Ted-SEA wrote:

> In my younger days when doing valve jobs for customers cars, I would clean
> off the carbon that was on top of the cylinders. I used to rotate the engine
> around and bring the pistons up to tdc and whirl away with a drill bit
> mounted wire brush.

The problem with this is that it will drop little bits of carbon goop down
between the piston and the cylinder, where they will make things sad.  
This is not the end of the world, but it doesn't do it any good, either.

Cleaning the carbon deposits off of the piston isn't really all that
important because they just come right back when the engine runs the next
time.

Last time I had the head off an engine, I used a little scraper tool to
scoop all the gunk onto the center of the piston, where I can vacuum it
up.  No gunk in the cylinder.

> should I leave it alone, ?

You may as well, unless there's a whole bunch of it.