Engineers consider the 2.0L engine the sweet spot for an inline 4 - big enough to produce useable power and small enough to not shake too much. And I can see using balance shafts in a four banger to give it that luxury car feel. But, why Mitsubishi wanted this for the Evo which already rides like an ox cart, is a mystery. Maybe it saves them from having to be careful about balancing parts during engine assembly. Dunno.

 

Thanks for the info, that's good to know. As long as the delete doesn't do any more damage than having the the bs intact. I've read about keeping the stock engine mounts and that's what i plan to do.

What do you mean by the front one? Is that stock or aftermarket?

 

Aby built his own motor

 

So a damper is designed to absorb vibration of the crank? But not the engine?
And everything connected to the crank that causes vibrations isn't absorbed by it?

That makes zero sense at all.

 

Use a stub shaft

 

Read this it helps to understand what the Fluidampr does.

http://www.fluidampr.com/HOWITWORKS.htm

"Why your engine needs a damper:
Each time the air/fuel mixture inside a cylinder is ignited, the combustion that occurs creates a torque spike that is applied to the crankshaft through the piston and rod. This torque spike is so severe that it not only turns the crankshaft, it actually twists the crankshaft ahead of its normal rotation and then the crankshaft rebounds. This twisting action is known as torsional vibration. When these torque spikes and forces get into phase with the natural frequency, critical torsional harmonic vibrations occur and can be seriously destructive to the bearings and the crankshaft. Dampers are designed to control those destructive vibrations.

Rubber VS Silicone Fluid
Critical harmonic vibrations occur numerous times in a engine’s operating range. Stock rubber and elastomer-type dampers are frequency sensitive “tuned absorbers”, and work at only one critical frequency. In the case of a stock rubber damper, it is tuned for a factory engine’s critical harmonic vibrations. If you change the mass of pistons, rods, or the crankshaft, you change the natural frequency of the crankshaft assembly; therefore, the stock damper is no longer tuned to the new frequency of vibration, and you may be headed for early failure of expensive engine components. Dampers also create heat while they work, and rubber is a poor dissipator of heat. This heat and the exposure to the elements deteriorates rubber, causing it to crack and change durometer, which then leads to inertia ring slippage, damper failure, uncontrolled torsional vibration, and costly engine parts breakage."




-Bink

 

Back on topic, I´m running my built 2.0 4G63 without balance shafts and I can´t feel no crazy vibrations. In fact I´m surprised how nice it came.

My setup is 4G63, .040" over JE pistons, Carrillo rods, stock crank, stub shaft BS delete kit, Fluidampr pulley, Kelford 272 cams and stock mounts.

 

Bringing this back from the dead. So do we have a final conclusion? JAM says dont delete it, Jacks says don't do it. Does a fluidyne properly control internal engine harmonics with different engine rods and pistons? Or is the balancing shaft still needed to absorb those harmonics? This will be for my 2.4L.

 

^ I'm with you on this one. In all of my DSMs I have removed them but for my 2.3L Evo I do not want to because of the companies you mentioned. In fact Jacks Transmission has a page on why not to remove them. I think if the car is used for spirited driving and the occasional autox/roadrace then keeping them in is the best option. My car will be used a daily driver and I just don't see why the balance belt would snap. I've never had any issue with it at all.

 

Tony from JAM deleted my 2.3 stroker, I wanted to keep them because my other 2.3 from Buschur was giving false knock. Never had a problem with Burschur’s 2.3 So I did not want to get false knock I asked JAM to install them and Tony talked me out of it. 5000 Miles late motor is gone. So on my new build I am installing th BS.

 

Did you determine the cause of the failure?

 

Keep the shafts. Install Kevlar belts. Add inspection hole to check tension on shaft belt. Invest in self built oil pan (see thread EvoM) to maintain oil pressure in all circumstances. Add Fluidampr to account for any weight indifferences in aftermarket rod, pin and piston install ....Done!!!!

 

How could you be so certain that it was due to the balance shaft delete that the motor went out ? Only thing I can think of is oil pump failing due to some of the claims of the stubby shaft hurting the oil pump bearing. As a result there is the "machined down” balance shaft is what you want to use. So if your motor went because of the oil pump , its not that you removed the balance shafts, but more on what you replaced them with.

1. I have read numerous times directly and indirectly from engineers that the purpose of the balance shafts are for our butts . The shafts are tuned to cancel/minimize harmonic vibrations at a certain small rpm window/range.

2. I hope all those that are deleting the balance shafts are deleting both shafts. If you remove/disable only one shaft you will have excess vibrations and issues.