I had the balance shafts removed recently.

We left the rear balance shaft in and took out the front balance shaft cut the tip off and put it back in.

So far it has been running fine. I've been having some other issues with my tranny that I need to replace before I can make another run. The car sounds totally different and has a bit more vibration but revs quicker than before. I've been running it for over a week this way and no other issues have popped up.


bryan

 

Bet that was a pain to do

 

This is a PITA to do, but well worth it.

 

Steps Involved (Summary):

1. Jack car up on passenger side and remove wheel.
2. Remove accessory belt and water pump pulley+crank pulley.
3. Remove lower cross member (goes under oil pan)+oil pan.
4. Remove all timing belt covers (top+bottom).
5. Remove timing belt with tensioner tool.
6. Remove bolts to oil pump sprocket+rear balance shaft sprocket+crank sprocket.
6. Remove oil pump case+oil filter/cooler housing.
7. Remove front balance shaft.
8. Measure + Cut head off front balance shaft as short as possible, you will need to measure how much you need left to pop out of the oil pump rear housing.
9. Finally put everything back together.

I would replace the oil case gaskets+crank seal+oil pump seal. There is no oil pan gasket. You would use high temp RTV silicone for that. I would also have some Carb cleaner handy (lots) to use as cleaner. It will be messy with oil and you don't want oil on gaskets+silicone when putting it back together.


bryan

 

Worth it by means of gaining horsepower? It's something that rotates right?, I would guess that his mod works like a lighter flywheel, no more HP appears, but better able to use what's there. Probably more responsive engine.

Why did Mitsu put them there in the first place? I would assume so that it doesnt shake itself apart at high RPM?...or at least improve longevity of the engine? The 4G isnt exactly a smooth engine to begin with. I think RRE recommends that it's fine to remove them, is this something to do on a daily driver? thx

 

The balance shafts are there to cancel out vibrations... for some reason unknown to me the smaller the motor the more vibrations so a lot of 4 cylinders have them. However they hurt power. I took them out of my DSM and you get good torque and HP gains everywhere in the range, its a great mod and you can most definitely feel it.

 

It's simply to smooth out the engine+increase longevity. It's mainly all to make up for build tolerances as well.

Benefits:

Increased HP/TQ
Increased Engine Response
Decreased risk of balance shaft belt breaking
Decreased risk of killing oil pump due to balance shaft flexing. (happened to me)

Cons:

Decreased engine longevity
Decreased quiteness/smoothness.


I think the benefits out weigh the cons.

 

balance shafts are just that, they balance the motor and cancel vibration that would otherwise be transferred to the crank and motor mounts.

But your right, you free up parasitic losses, you don't directly gain power, but it becomes a measurable gain because of less mass to rotate..

 

Although isn't the stock EVO crank pretty well balanced? How would this hurt longevity?

Also wouldn't a DSM balance shaft removal kit work for an EVO too?

 

After you cut the shaft , you have to weld the hole in the stubby up. I hope you didn't skip this or you will have low oil pressure . The balance shaft bearing of the shaft you cut is fed oil through the shaft. After you cut the shaft there will be a nices 1/4 " oil passage that needs to be blocked off.

 

question, i want to remove my balance shaft completely, i have the eliminator kit from my old engine, could i preform this, using the steps you used to remove your balance shaft? do you know if i would be able to install the pieces for the eliminator kit becuase i cant afford having my engine taken out, and i dont have enough experience working on internals like this...

 

This will get you experience and a lot of it. It is not for the faint of heart.

 

lol i want to do it, but i dont want to risk making problems worse, i just need the car working right nowww

 

Anyone removing the balance shafts should do it the right way and remove both shafts 100% and use the oem parts to replace what you removed. Cutting the old shaft and leaving one in there is GHETTO and a true sign of someone who should NOT be working on your car. If that is the quality work you do enjoy a POS Evo. In a few years all these hack jobs will be "problem" cars just like DSM's because people are either to cheap or too stupid to do the job right.