Syl's Sydney Homestay wrote:
>
> Barney thanks for your fullsome report on engine balancing.
>
> To what extent does prop shaft balancing have on the total equation do you
> reckon?
Driveshaft RE balancing (it's done at the factory as well, but to a
lower level) can improve the ride comfort considerably. Even more
important is the need to keep an eye on your U joints. They are among
the smallest of the ones available and wear quite rapidly, especially if
neglected at lube time. The first symptom is usually a mysterious
vibration in your rear view mirror, with progressive damage if ignored.
Midgets, TC-TF MGA and MGB all use the same size, so imagine how much
more stress an 1800 puts on them than a 950!
One thing Barney didn't bring up. Balancing is like having overdrive. It
usually can never pay back in terms of gas mileage or longevity, but it
makes a world of difference in terms of engine noise, feel, and comfort.
"Blueprinting" an engine is simply the process of modifying all the
parts of it to (as nearly as possible) match the exact specifications of
the original engineering specs. In manufacturing, all parts have a
"tolerance" and vary from design specs to a greater or lesser degree.
Balancing is merely the process of bringing the masses of the moving
parts closer to "spec". For an expensive car, the tolerances are
decreased, and presto - a smoother engine!.
Did you know the volume of your combustion chambers can vary by more
than a cc? This can cause the compression ratio to vary by a 10th of a
point or more! Want to bet whether that makes your engine run rougher
than it could? "CC ing" an engine involves measuring your head and
balancing the chambers and is another step in blueprinting.
As cylinder heads are cast, the sand cores used for the ports wear down
and today's heads can have intake and exhaust ports that are up to 15%
smaller than "spec"compared to those cast just a few days ago. Wonder
why yours always feels like a "monday car" while your buddy's always
runs rings around you? They were built the same day, but he has about 6
more horses? Some things to ponder. Jarl
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