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Discussion Starter #1
I've had my balance shafts removed for a couple weeks now and figured I report some pros and cons I've found:

Pros:
1. Better throttle response-the engine responds better to throttle input and revs faster.
2. Easier clutch engagement-I don't know if this is an imaginary feeling but after install the clutch was easier to engage smoothly in first gear.
3. OIL JETS-When I was looking over the oil system diagram for this car http://forum.mazda6tech.com/viewtopic.php?t=4207 I noticed that the oil jets and balance shafts share the same supply. This is a problem because the shafts must always have oil while the sprayers have check valves built in. By plugging up the supply to the shafts all that oil now goes to the sprayers only so I'm assuming they are functioning more of the time.
4. Oil capacity-Up to 7 qts now-The advantage to this is that there is now more oil in the pan for the pickup to sit in.

Cons:
1. PITA to install-If you don't have a completely free day, a good set of tools, and a desire to get COVERED in oil than I don't recommend you try this. It is not the average DIY install.
2. Oil Capacity-oil costs money and man is synthetic expensive.

For those of you wondering, when I first installed this I did notice a very slight increase in vibration at idle while holding onto the steering wheel with both hands and trying to feel an increase. Now that I've had it for a while I don't even notice so I don't consider it a con. Hope you guys like the info.
 

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I wouldent screw around with balance shafts on a street driven car. Harmonic and rotational balance is crucial to the longetivity of your bearings and internal components. On a racecar it dosent really matter but on a street car I will adversely effect the life of your motor.
 

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Discussion Starter #4
This kit is for the 2.3 block. I dont think v6 even come with balance shafts, it's an inline 4 thing.
 

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balance shaft has nothing to do with engine balancing on the 2.3...it's for NVH, what the passenger feels.

i can do this in about 2 hours now, so if any SoCal people wanna do it, swing by!
 

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balance shaft has nothing to do with engine balancing on the 2.3...it's for NVH, what the passenger feels.

i can do this in about 2 hours now, so if any SoCal people wanna do it, swing by!
[/b]

How is a naturaly unbalanced configuration like an inline-4 supposed to cancel out inertial and kinetic vibration. Its physycally impossible to have primary balance in a 4 cyl engine without a balance shaft.

http://en.wikipedia.org/wiki/Balance_shaft

http://en.wikipedia.org/wiki/Straight-4


Inertial vibration only gets worse expotentially as revs rise.
 

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Balance shafts DO NOT balance the crankshaft! Think about it, how can something that is on a different axis of rotation have any bearing on the balance of the crank. That would be like trying to balnce your crank with an accesory. All they do is create their own vibrations that are timed so they cancel out the vibrations of the engine. They are used for comfort and refinement.
 

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Balance shafts DO NOT balance the crankshaft! Think about it, how can something that is on a different axis of rotation have any bearing on the balance of the crank. That would be like trying to balnce your crank with an accesory. All they do is create their own vibrations that are timed so they cancel out the vibrations of the engine. They are used for comfort and refinement.
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They do not balance the crankshaft itself it balances the entire rotational assembly with the pistons and rods attached. An inline 4 configuration is naturally unbalanced. There is primary and secondary phase vibrations resulting from the rotational assembly. If the engine were naturally balanced it wouldent need balance shafts because it wouldent produce phased vibrations.

This issue has been debated for ages.

My philosophy has always been why bother and has been reflected from the many problems people have in the nissan community with the unbalanced motors setting off knock sensors resulting in the loss of horsepower.

There are much easier and less contraversial ways to reduce rotational mass including lightening your flywheel.
 

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correct, which is why the ranger, wiht the same block, does not have the BS. who cares if a truck has vibration, but when you are in a small car, with street tires like the focus and mazda...it's "important".

there are plenty of 4's without balance shafts, take a look...wikipedia.org/wiki/go look on google or something
 

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The ford ranger motor isnt exactly a high revving high performance motor. Vibrations increase expotentially with revs.

Additionaly first harmonic vibration is greatly amplified by the fact that turbochaged cars produce more powerful combustion cycles.

Of course this can be debated for ages. I will state that it is my researched OPINION that removing the balance shaft on a relatively high revving high performance, long stroke, undersquare motor will not be worth the modest gains that it may give as there are certainly better ways to increase throttle response and power.

This is my line of reasoning and im not saying it is definative but I beleive it does make sense.

1) Inline 4 cyl motors are naturally unbalanced.

2) 2.3 liters is on the large side of a 4 cyl engine and has alot of reciprocationg mass.

3) The motor is undersquare. Meaning the bore is smaller than the stroke. Compared to square or overrsquare motors piston speeds are higher per rotation. This results in a bunch more kinetic vibration.

4) In the past when the nissan guys were ditching thier balance shafts they would get negative Knock correction and loss of power because the engine vibration was setting off the knock sensor and masking/emulating true knock.

5) The motor is relatively high revving and has higher peak cylnder pressures than a normal engine.

Of course YMMV and you are all wecome to try it if you wish as Other people DO have valid arguements as well.

EDIT: Edited to remove errors.
 

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agreed, there are no for sure, easy mods. everything has some sort of downside. every mod should be done at your own risk.
 

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Well, Let's see???
I have an 240sx running a KA24DE with NO balance shaft and no balance wieght on the Crankpulley. As I have replaced the pulley with a High performance pulley and replaced the Cams with Higher Lobe action. At 138K I tore the engine down to replace the Head.. Why? I over rev'd it a few times on the track in Oregon and Canada and Before I was supposed to run at Laguna. So I messed up and spun the Intake cam and mushed the valves.
In 70+ K of miles, with a couple hundred being on track, I had no vibration/Harmonics problems.
Now, the KA is a LONG stroke and the MS6 is on the edge of being a long stroke, so the vibration may be more of an issue due to piston travel and RPM. Yet, on that, the MS6 is NOT by any means a HIGH rev'r. My 240sx redline is 7500 and I always hit 6800-7k. The MS6 can't get there from here.
It would be interesting to see though. Also this action has been done to the Sentra SE-R and really has not proven Dyno improvements. It is mostly for rolling response, as the flywheel and the rims would be. OH and a CF/Alum single piece driveshaft
 

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I guess if u have any problems with bearing wear or engine failure let us know ,and that may have been a contribution to it ,if no probs theres ure answer to that .I have (heard) that putting a udp in place of a h/b set up increases overall engine vibration witch would cause brg failure but have never heard of that being any cause of engine failure .So this will prolly just lead to many arguements like many other posts.
 

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The ford ranger motor isnt exactly a high revving high performance motor. Vibrations increase expotentially with revs.

. . . .

3) The motor is oversquare. Meaning the bore is smaller than the stroke. Compared to square or undersquare motors piston speeds are higher per rotation. This results in a bunch more kinetic vibration.

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Dude, call me picky, but you create confusion and undermine your credibility somewhat by calling the MS6 engine oversquare. The MS6 is undersquare with a 3.4 bore x 3.7 stroke, except (apparently) if you are Finnish or a native of a few other unnamed countries (http://en.wikipedia.org/wiki/Stroke_ratio). :goon:
 

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Dude, call me picky, but you create confusion and undermine your credibility somewhat by calling the MS6 engine oversquare. The MS6 is undersquare with a 3.4 bore x 3.7 stroke, except (apparently) if you are Finnish or a native of a few other unnamed countries (http://en.wikipedia.org/wiki/Stroke_ratio). :goon:
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Sorry about that, you are correct. I reread my statement. What I meant to say is that the bore is shorter than the stroke which is undersquare.

Your not picky its a good catch and was my error. I will be the first to admit when somthing is wrong.
 

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anyone who was in the DSM world formerly or currently know also that it is almost a given when you rebuild your 2.0 turbo that you remove the balance shafts for more power/quicker response. No adverse affects on those engines.
 

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anyone who was in the DSM world formerly or currently know also that it is almost a given when you rebuild your 2.0 turbo that you remove the balance shafts for more power/quicker response. No adverse affects on those engines.
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Except crankwalk... :lol: JK. :D The two are probably completely unrelated.

The case is debatable as I said earlier. There are case scenarios that support either. But normally when you build your motor you put stuff in there that is way stronger than stock.

Nobody has a definative answer but I thought it would be right to let people know the other side of the arguement and let them make up thier own decision.
 

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Except crankwalk... :lol: JK. :D The two are probably completely unrelated.

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Crankwalk is no where near related.

The only adverse changes to the motor when removing balance shafts (on a 4g63) is increased oil pressure and increased vibration (duh!).

Add in some prothane motor mounts and you drive a regular old vibrator waiting to please the women. :p

Jason
 
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