<< He abused the h*ll out of my fresh rebuilt, not nearly broken in engine
trying to diagnose the noise. Now I wish I'd not let him in it. >>
How many miles on the rebuild and how do you define abuse?
Harold,
You are probably right and I'm sure he knows what he's doing. I realize race
engines get about one 15 minute practice session before really hard use. My
motor probably has over an hour on it.
It did make me wince though to have the brakes and gas applied (both hard)
simultaniously several times to load the motor. Oil pressure still 70+
though and apparently no harm done.
Anyway, just happy to have the thing running with no major defects now.
Curt
Visit: CurtFisherRacing.com
"Racing is life, anything that comes before, or after is just waiting",
Steve McQueen from Le Mans.
-----Original Message-----
From: ZinkZ10C@aol.com [mailto:ZinkZ10C@aol.com]
Sent: Saturday, May 12, 2007 8:42 AM
To: Fisher, Curt (Dixon); triumphs@autox.team.net
Subject: Re: [TR] disturbing knock- resolved
In a message dated 5/12/07 8:33:35 AM Eastern Daylight Time,
cfisher@borgwarner.com writes:
<< He abused the h*ll out of my fresh rebuilt, not nearly broken in engine
trying to diagnose the noise. Now I wish I'd not let him in it. >>
How many miles on the rebuild and how do you define abuse?
Having had owned a auto repair shop and building countless regular and race
motors, 85 % of the ring break in occurs in the first 15 minutes of engine
operation if the bores have the proper finish. Over the next 20 miles you
are up
to 90%. Complete ring break in occurs by 200 miles or so.
For proper ring break in, the motor needs to see high cylinder pressure
otherwise the honing peaks will just roll over and not scrub the rings. (
think of
the cylinder honing marks as fine sand paper) Spirited city driving 0 to 45
then back to 0 is great for break in as would a 1/2 mile oval race track.
The issue with break in is to avoid sustained high load ( towing a trailer )
and red line RPM for the first 100 miles or so.
My oval track car ( 307 Oldsmobile V8) gets a 75% speed 6 lap on track
session then full speed next time out. After 1 1/2 seasons the bores are
just fine.
Even though actual track miles are in the 500 range, all of those miles are
at 4500 to 5300 RPM range. The engine wear under these conditions would be
more like 40,000 miles.
Harold
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