I guess you're right.
I'm just trying to figure out if removing my balance shafts will impact the longevity of the motor. So far everyone says it has no effect on longevity without any supporting evidence. All I'm asking for is evidence so I can make an informed decision.

 

For sure. Good luck with the search!

 

starting the engine has a negative impact on its longevity . On a more serious note though, I'm skeptical the kind of "evidence" your looking for exists. Even if such a study was done, with all the variables controlled for, it would still only be valid under a very narrow set of circumstances. In the wild things often play out a lot differently. I believe whats been presented here is as good as one could expect in this type of forum. Maybe there is some den of SAE nerds out there in some other forum you could bounce this off of.

 

This is the conclusion I've come to, unfortunately I could not find any legitimate research papers on the topic. If you know of any SAE Nerd-Dens be sure to let me know haha, I'd love to hear their opinions.
I'm at the point of I really just don't know whether to retain my BS or not. There's not enough reason to remove it for me personally, so I'll probably end up keeping it. Even if it's just an NVH thing, I'd prefer the engine to run and feel smoother. As long as the belt is of good quality and properly tensioned to factory spec, it should not introduce any issues. Would be nice to save some time on timing belt changes, however.

 

That and eliminating any source of failure is a good thing. One less thing to worry about! But like I said: I had a brand new belt shred and almost kill an engine. So, I'm biased. LOL

 

I totally feel you there. The less things that can fail the better. Let me ask you though, are you sure the belt was tensioned properly? They need very little tension, just enough to keep the belt from skipping teeth. Is there any possibility it was too tight? Also which belt did you use?

 

Actually, I thought about it and it doesn't matter to me. If it were part failure or user error... it could have killed the engine, either way. So, I started looking for ways to make it not an issue. That's when I decided to ditch the balance shafts. That took care of all variables.

 

That's totally reasonable. In my opinion the only variable left is whether the BS can extend the life of internal components, which is why I'm still on the fence as to whether I want to keep it or not. Eliminating the possibility of error is typically a plus, I'm just unsure as to what cost that comes with. To be fair, I don't think anyone knows. We'd need to hear from someone who actually has experience designing an i4 engine, which is really just a tiny subset of people.

 

Heres an in depth White Paper PDF on crankshaft harmonics & the damage that occurs at certain frequencies. Its V8 related but some of the frequency principles may apply?

 

This paper goes into effects of torsional vibration in the crankshaft, not quite what the BS is designed to deal with. I think we're all in agreement with the damage torsional vibration can cause and that removing harmonic balancer is a big no-no. The argument is over whether 2nd order vibrations(which are attenuated by the balance shaft) will also cause similar wear. Unfortunately there's not many white papers that specifically focus on 2nd order vibration and the effect a balance shaft has on them. Correct me if I'm wrong, though, this is mostly speculation.

 

People probably aren't going to write a paper about a problem until it exists.

 

One would hope that there's at least papers that led to the implementation of the BS in the first place. That's really what I'm after. I'm definitely not expecting a "Effects of Balance Shaft Removal on Inline 4 Cylinder Engines" paper haha. Although that would be sweet...

 

I think it's more like "F it..just do something so they stop complaining about the dash rattling".

Not worthy of a paper. I don't think Mitsubishi gives two craps, to be honest (based on lack of data).

 

It just seems weird that they wouldn't just run a slightly softer durometer engine bushing. To be fair though, I hate dash rattle so I don't blame them haha.

 

Who knows why they chose this route, 20yrs ago.