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Originally Posted by d0zxmustang
Have you acually ever looked at a F2 crank? What do you think those drilled holes in the crank are? They are balanced from the factory. If they werent, they would blow apart on the dealers lot.
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Um, like I said before, It simply doesn't matter if the crank shaft has been balanced or not. Without changing the configuration(e.g. to horizonally opposed,- aka boxer style) or adding balancer shafts (like the MZR line), then 4 cylinder engines are *never* balanced - the order of piston firing creates end to end vibrations. Period.
I'm not going argue any more, the stock main crankshaft pulley *is* a damped pulley. And *no* you do not use epoxy on a harmonic balancer - you use rubber, and it doesn't have to be very thick - in fact, the thickness is related to what rpm speeds it most effectively dampens out.
I'm against mis-information. As long as people understand *exactly* what a lightweight pulley does for them, that's fine . I don't want any ignorant people buying a lightweight flywheel pulley. That is one thing which sets MX6.com apart from many many many other Car related websites.
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Originally Posted by d0zxmustang
attachments are balaced independantly. As long as the flywheel and pulley are balanced within a resonable range, there will be know problem.
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I dunno wtf yer talkin bout, willis, butcher dangonne englush skelz ar sou pour dat ah donut think yah NO whatcha talkin bout.
Seriously, V8 engines can get away with little to no harmonic balancers. Straight 6 engines don't need them either. Straight five cylinders only need them if they want to reliable run at high rpms. BUT 4 cylinder engines are the worst. Why don't you read some of my links above, dealing with engine smoothness. Jake didn't get why I posted those at first, because they had *nothing* To do with harmonic balancers, rather it had to do with why engines aren't smooth, aka, why they vibrate.
There are numerous 4 cylinder engines which have the balancer shafts, for example the F22 series from Honda,
Aww, crapnuts, read this for another explaination:
Straight-4 - Wikipedia, the free encyclopedia
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Originally Posted by Wikipedia
Balance and smoothness
The straight-4 engine is much smoother than one, two, and three cylinder engines, and this has resulted in it becoming the engine of choice for most economy cars. However, the straight-4 is not a fully balanced configuration. While it is in primary balance because one pair of pistons is always moving up at the same time as the other pair is moving down, piston speed - as with all internal combustion engines - is higher through the top 180 degrees of the crankshaft rotation than the bottom 180 degrees. Since two pistons are always moving faster in one direction while two others are moving more slowly in the other, this leads to a secondary dynamic imbalance - an up-and-down vibration at twice crankshaft speed. This imbalance is tolerable in a small, low-displacement, low-power configuration, but the vibrations get worse with increasing size and power.
Most straight-4 engines below 2.0 L in displacement rely on the damping effect of their engine mounts to reduce the vibrations to acceptable levels. Above 2.0 L, most modern straight-4 engines now use balance shafts to eliminate the second-order imbalance. A straight-4 needs two balance shafts, rotating in opposite directions at twice crankshaft speed, to offset the differences in piston speed. Nevertheless, in the past there were several samples of larger straight-4s in production using no balance shafts, such as the Citroën DS 23 2347 cc engine that was a derivative of the Traction Avant engine, the 1948 Austin 2660 cc engine used in the Austin-Healey 100 and Austin Atlantic, the 3.3 L flathead engine used in the Ford Model A (1927), and the 2.5 L GM Iron Duke engine used in a number of American cars and trucks. These engines were generally the result of a long incremental evolution process and their power was kept relatively low compared to their capacity.
Four-cycle four cylinder engines have another problem in that the power strokes of the pistons do not overlap. With four cylinders and four cycles to complete, each piston must complete its power stroke and come to a complete stop before the next piston can start a new power stroke, resulting in a pause between each power stroke and a pulsating delivery of power. In engines with more cylinders, the power strokes overlap, which gives them a smoother delivery of power and less vibration than a four can achieve. As a result, six and eight cylinder engines are generally used in more luxurious and expensive cars.
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