You need heat and pressure to get the engine broken in. If it has
rings, they won't seat without that pressure; they'll instead glaze
themselves and the cylinder wall and leak forever after. The engine
needs to be run.
On Wed, 22 Nov 2006 16:21:17 GMT, "Mark Daughtry, SR"
On ABC or ABN engines the cylinder sleeve is designed to account for expansion
in the presence of combustion heat in the upper part of the bore (the
so-called "tapered bore"). And the piston is designed for optimal fit at
operating temperature. Your scheme takes combustion heat out of the equation.
I suspect only bad things could happen...
It was an interesting question and it elicited some
interesting answers. Way to go, Mark!
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I also wonder how heat cycling in the metals may be involved.
Some metals have their characteristics change, quite drastically, when going
though cycles of heating and cooling, usually to the benefit of strength and
hardness of the metal. I'm thinking this may be involved, also.
Absolutely. Stresses built up in casting and machining are relieved, so
the combination of heat and well-lubricated friction are both critical
to a good break in. Maybe a better term is "running in," a term that
was once common, but seldom heard nowadays.
And remember, there are no stupid questions, just stupid answers! :-)
I'd say no for several reasons:
1. That oil isn't "dripping" into a chamber thrashing around at 10000+RPM,
it's being sucked and blown out via the exhaust and the glow plug hole. A
lovely oily mess that replicates nothing the engine does when operating.
2. There is no combustion and thus no equivalent pressure levels,. heat,
loads etc to replicate typical engine conditions. You're relying on bare
friction of the cylinder and piston (modified by your mess of oil) as the
sole means of running in the engine.
3. Explain how a typical two stroke engine using a ported crank is going to
wear with no lubricants passing through the carb, shaft, crankcase, bearings
and, schnurel (sp?) ports. Your method only lubes the upper cylinder and
4. Your driving a load into the engine via the crank, which is backwards to
how an engine normally runs (drive comes out the crank). Hence, you're not
replicating how the engine really operates and thus not how it would
typically run in.
The easiest and proven way of running in an engine is to actually run it,
ideally according to what the manufacturer has found to work best for their
You had an interesting idea, but I wouldn't use it.
Back in my U/C days it was not an uncommon practice to "motor" a Fox .35 in
a drill press with light oil supplied to the venturi for 12 - 24 hours.
Reduced the normal 5 gallon break-in to 1 or 2 gallons. There was also a
product called lustre something that would supposedly accomplish the same
thing but it was easy to over do. Alas this was a lapped iron piston &
sleeve. I wouldn't recommend it with any other type engine.
You're thinking of Fox "Lustrox", which was a mildly abrasive powder that
you mixed with castor and dabbed into the venturi of a running lapped piston
engine.... Too much and you were in the market for a new piston and
Yep, That's the stuff. My LHS used to keep it behind the counter and give
out stern warnings to anyone who would dare to use it. I never tried it.
Lots of good memories have been brought to mind by this thread.
I watched two fellows use Lustrox to seat the ring in a large block Fox .45
BB engine. Guess what else they "seated"? <G>
I warned them, but was not so politely told to mind my own business. So I
didn't feel so bad when I couldn't stifle the laughter at the results of
trashed bearings and a ruined crankcase/crankshaft fit.
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