Should I remove my COBB to increase reliability?

[PJB]

You are correct on the balance shaft issue with the #3 rod. This was the point of breakage on the engine I had. The mechanic at the dealer did tell me it looked very strange when he pulled the pan off the engine that the studs were pulled out of the balance shaft assembly.

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[Juben]

I'm genuinely curious if something in the design of the BS could be the root contributing factor to the failures. It'd almost make it worth yanking the pan and doing the delete just to be safe.

If you really think about it, what kind of effect(s) will the parasitic drag of driving balance shafts have on the crankshaft and what would happen if the balance shafts saw some kind of reduced oiling event and seized up a hair? Food for thought. If you've ever seen the inside of one of these engines and the balance shaft setup (carriage, assembly, oiling), then you'd know why I'm curious.

 

[PJB]

I'm genuinely curious if something in the design of the BS could be the root contributing factor to the failures. It'd almost make it worth yanking the pan and doing the delete just to be safe.

If you really think about it, what kind of effect(s) will the parasitic drag of driving balance shafts have on the crankshaft and what would happen if the balance shafts saw some kind of reduced oiling event and seized up a hair? Food for thought. If you've ever seen the inside of one of these engines and the balance shaft setup (carriage, assembly, oiling), then you'd know why I'm curious.

Juben, it makes sense what you have stated. One of my hobbies is antique tractors since I grew up on a farm. I got to thinking back on the balance shaft issue and remembering an issue associated with a tractor that was introduced in 1960, a 3010 John Deere, by the way I am not that old. I want to give a quote from an engineer at Deere that I found below. The 3010 with the 4 cylinder engine was the first of it's kind for Deere. They had a lot of issues having to be returned to the factory for balance shaft issues which was new to the company. It was corrected in the next model Deere put out in the 3020. With this being said what you are talking about with the oiling and bearing issue was happening with this tractor. Here is a quote from an engineer at Deere from an engineering book within Deere.
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1) The geometric in-balance:

"An even-firing inline-four engine is in primary balance because the pistons are moving in pairs, and one pair of pistons is always moving up at the same time as the other pair is moving down. However, piston acceleration and deceleration are greater in the top half of the crankshaft rotation than in the bottom half, because the connecting rods are not infinitely long, resulting in a non sinusoidal motion.[improper synthesis?][disputed – discuss] As a result, two pistons are always accelerating faster in one direction, while the other two are accelerating more slowly in the other direction, which leads to a secondary dynamic imbalance that causes 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.

The reason for the piston's higher speed during the 180° rotation from mid-stroke through top-dead-center, and back to mid-stroke, is that the minor contribution to the piston's up/down movement from the connecting rod's change of angle here has the same direction as the major contribution to the piston's up/down movement from the up/down movement of the crank pin. By contrast, during the 180° rotation from mid-stroke through bottom-dead-center and back to mid-stroke, the minor contribution to the piston's up/down movement from the connecting rod's change of angle has the opposite direction of the major contribution to the piston's up/down movement from the up/down movement of the crank pin."

2) The power pulse cause of in-balance:

"Four-cylinder engines also have a smoothness problem in that the power strokes of the pistons do not overlap. With four cylinders and four strokes to complete in the four-stroke cycle, 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."

There are ways other than balancers to reduce the vibration but then you have other limits.

Making the block taller so you can have longer connecting rods will reduct the geometric vibration but not the power pulse vibration.

Making the engine cylinders a "V" shape helps the geometric balance.

There is no simple way to counter the power pulse problem without balancers.

So there are the reasons behind the balancers. Why some brands used them and others did not. That was a choice they made on how smooth they wanted their engines to be.
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I know some posters will laugh because I threw in a comparability with a tractor to a car but a lot of the same engineering exists between the 2. This is just my 2 cents to throw in.

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