RE: More on bead blasting

["Brian Shorey" <bshorey@domain.elided>]

> >I have been advised by several serious Alfa engine builders
> >through the years to NEVER bead blast anything inside the engine.
> >I know, some one will now undoubtedly say  "I 've been doing this for the
> >last 100 years with no problems ". So be it.  FYI.
>
> You'll admit this advice, however well intentioned, is heresay.
>
> Some things are OK to bead blast or even desirable. Others, such as
> mentioned in prior post, not. Cylinder heads, f'rinstance, are routinely
> bead blasted. Regardless, parts must be clean.  While it's not necessarily
> a bad idea to bead blast water passages (i.e., which is more abrassive,
> glass beads or aluminum oxide?) it would generally be a bad idea to bead
> blast an oil passage, at least if it were difficult to clean and inspect.
> Likewise ring lands and the other things mentioned, since the surface
> finish, etc. effects function, should be left alone. You were probably
> advised not bead blast for fear you'd bead blast the wrong things, with
the
> wrong blast media, with dirty blast media, wouldn't clean the parts
> properly after blasting, etc.

Actually, I think I've heard the same thing as Tom Lesko, and I seem to
remember hearing it from a well-known engine builder in this area.

From memory, what I was told was that with aluminum, fragments from the
beads can embed themselves into the surface and cause trouble at a later
time.  Things like camshafts wearing out in 20k miles, etc.

In fact, I seem to remember being told this as he was showing me the
condition of a cylinder head with 20k miles on it that had been bead
blasted.

Now it could be that the person who did the bead blasting blasted things he
shouldn't have, but I got the impression that it was the nature of the
aluminum that was the issue.

Fwiw,

bs

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