<VV> RE: Zero Compression update 3 and engine brake in period question

John Kepler bigjohnohio@worldnet.att.net
Thu, 12 Aug 2004 08:31:59 -0400

> All the replies I received said do not use non-detergent oil.  Does
> disagree with Clarks?

Yep!  Pretty much!  Clark's position reflects on school of thought, everyone
else another.

Here's the science and reasoning behind BOTH positions.  In a new and/or
rebuilt engine, it is inevitable that a small amount of "machining
residue"...read that as fine metal shavings, are going to be generated by
both the machining itself, no matter how hard the parts are cleaned, and by
various machined surfaces "wearing in" (FWIW, an old Soviet T55/T62 Tank
Engine lost as much as 5 lbs of metal during break-in...the parts themselves
doing the final machining....you can tell just how new a Soviet tank engine
was by looking at the smoke....a new one belched white smoke, and old one
belched black smoke!).  It's how to deal with that displaced metal that's at
the heart of the problem.

Clark's (Old) School Reasoning:

The displaced metal is bad and you don't want it circulating around the
engine raising hell, so you want the particles to drop out of the oil as
fast as possible....so a short "break-in" period with non-detergent oil is
what you want.  This position is as old as detergent motor oils, and has
always had some snake oil attached to it by those that felt that detergent
oils were the Devil's Spawn in the first place!  There ARE some logical
flaws in it, mainly centering on just what is going to make the metal
immediately "drop out" of the oil rather than being cycled through it
multiple times, and once it does drop out...why is it going to be removed
when the break-in oil is changed.

New School Reasoning:

The displaced metal is bad and you don't want it circulating around the
engine raising hell, so you want the particles suspended in the oil as fast
as possible and then completely removed from the engine for good by the
filter....so a short "break-in" period with high detergent oil and a
damn-good oil filter is what you want.  Your break-in procedure should be
built around the concept of moving any displaced metal to the oil filter as
rapidly as possible, and getting rid of it for good.  FWIW, this is the
procedure that all auto companies use (the OEM filter in a new car is fairly
special, with a finer filter media just to trap that displaced metal from a
new engine!).

As for the Synthetic Oils:  The extremely high film-strength and lubricity
of synthetics prevents the rings from seating rapidly (read that as "wearing
in").  The rings WILL eventually seat with a synthetic, but it's going to
take a while, and in the mean time,oil consumption will be abnormally high
causing just all kinds of potential problems.  In new racing engines, we did
the break-in with mineral oil on the dyno for about 30 minutes, drained it,
and then replaced it with synthetic.