What would this do... (technobabble)

[amalventano1@comcast.net (Allyn)]

1. when cold, the oil is too viscous. in extreme cases, its so thick that it
cant properly flow into areas of tight tolerance, resulting in those areas
wearing. keep that up a few times and eventually you have something major go.
2. your engine does not warm up evenly. during the warmup process there are
large differences in temperature across the thick portions of the block/head.
this temperature difference results in high tensile stresses in some areas.
throwing high rpm stresses in there may be enough to make some preexisting flaw
start spreading into a large crack.
3. operation at high rpm implies faster heatup of the metal (due to faster
combustion/friction/etc), making the temperature difference greater, and the
tensile stresses (#2) even higher.
4. when cold, metal has a lower stress point where it will fracture. this makes
#2 even worse if the stresses are in an area that hasnt warmed up yet.

other babble to throw around:
Fracture toughness (KIC): ability of a metal to prevent a preexisting crack from
propogating under a given tensile stress level.
Thermal stresses: tensile stresses due to temperature difference across an
object.

side note: there are very specific rules for running reactors that govern rates
that you can heat up/cool down. they get much more restrictive the colder you
go. reactors arent much different than engines, as both are just hunks of metal.

HTH
Al

Allyn Malventano, ETC(SS), USN
87 Rieger GTO Scirocco 16v (daily driver, 180k, rocco #6)
86 Kamei Twin 16V Turbo Scirocco GTX ('it has begun', rocco #7)
86.5 Occo 16v Trailer (dotting 'i's across the country, rocco #8)
87 Jetta 8v Wolfsburg 2dr (daily driver, 260k, 0 rattles, original clutch,
driveshafts, wheels :)

----- Original Message -----
From: "Vince Royer" <vince@performancecarstereo.com>
To: "Scirocco List" <scirocco-L@scirocco.org>
Sent: Friday, October 04, 2002 2:40 PM
Subject: What would this do...


> Hey guys,
>
> Just a little fun question to throw at you.  Does anybody have any detailed
> examples of what might happen If I were to run my motor at really high RPM's
> while it's cold, perhaps repeatedly.
>
> I'm looking for things like metal chips in the oil, loss of compression,
> etc.  I need realistic answers to things that would actually happen, so that
> I can explain them as if they did happen and somebody would believe me, even
> a mechanic, or an insurance adjuster or something.
>
> Go nuts.
>
> Vince
>
>
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