Ed;
HRM has an article on coatings that seems to support what you are
saying. The only coatings that made worthwhile HP improvements were the
ones having to do with heat, not oil- shedding.
Regards, Neil Tucson, AZ
-----Original Message-----
From: owner-land-speed@autox.team.net
[mailto:owner-land-speed@autox.team.net] On Behalf Of Ed Weldon
Sent: Wednesday, October 18, 2006 11:07 AM
To: land-speed@autox.team.net; Higginbotham Land Speed Racing
Subject: Re: Internal Engine Block Painting
Skip--Only use it on the as cast surfaces. What you're trying to seal
in is
the casting core sand particles, sand grit from the foundry final
cleanup
process that involves the uses of abrasive grinders as well as tramp
rust,
scale and dirt in corners and pores. I would not attempt to use it on
any
machined surfaces especially where the surface can't be roughened to
provide
a good grip for the coating. Don't attempt to put it in any drilled
holes.
You'll likely restrict the flow rather than improving it. If you're
marginal with oil feed holes drill them larger or at least chamfer the
edges
at the openings (Which will likely help your own feelings more than the
flow
losses of the oil)
I remain unconvinced that any improvement on the surface finish of oil
passageways will have any measurable effect on flow rate. Virtually all
oil
flow is in the regime of laminar flow where surface roughness is not a
factor. The classic engineering pipe friction curves for friction
factor at
various Reynolds numbers shows this. It's a whole different issue for
thin
liquids like water, gasoline and alcohol. In the size lines we use the
flow
is turbulent and pipe roughness counts. But nowhere near as much as the
actual area of the pipe flow path (the diameter in most cases).
Ed Weldon
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