Balance shaft elimination tips...

[pitboss]

I too had a similar problem with my 91 talon tsi... Quite a few people along with the dyno shop told me I had phantom knock and I spent the good part of 2 weeks taking everything apart and slowly putting it all back together with lock washers and locktite to make sure everything was tight and making sure nothing touched and I went to extremes to try and find the "phantom knock", it was still there, after 2 months of trying this and trying that, a friend of mine asked what I thought to be at first a dumb question... You have your balance shafts eliminated dont you... Then it hit me, DUH, so I pulled the motor apart, had the flywheel mated to the crank along with the crank pulley and balanced as one assembily, balanced the piston rod combo, put it all back together, phantom knock was gone. The only thing I can guess is the harmonic distortion inside the motor due to the shafts being gone caused the phantom knock.

 

Thanks for posting that, because I was starting to think I'm crazy. That must be what my issue is then as I was thinking, because 92 octane didn't help eliminate the "knock" and I know the BS were taken out. My guess is the crank wasn't rebalanced when they were removed, so now I have the phantom knock too. I'm the fourth owner of this car. Its an auto car though, so there is no buzzing anywhere. Maybe the heavy torque converter and all the fluid and the overal weight of the tranny disipates the vibrations, but the knock sensor still thinks there's knock, so my LED goes out at 4500 rpm almost on the dot everytime, even if I'm NOT on boost.

[funbunion]

Yeah, my brother had his removed when he had his engine rebuilt, he says he can't tell much difference in response or power. On the flip side, he doesn't really even notice any extra vibration in his.

I may do this as a preemptive action to remove another break point down the road.

[Metric-man]

According to Wikipedia the asymmetric motion is caused by the pistons if they are not full floaters,

therefore if your engines pistons are bushed for full float (range of motion) pins, you do not need the silent shafts.

 

http://en.wikipedia.org/wiki/Mitsubishi_4B1_engine

 

4B11T

Specifications

Engine type Inline 4 cylinder DOHC 16v, Turbo MIVEC

Displacement 2.0 L (1998 cc)

Bore 86 mm

Stroke 86 mm

Compression ratio 9:1

Fuel system ECI multiple

Peak power 206 kW (280 PS) at 6500 rpm &152hp @6000rpm(Japanese market)

217 kW (291 PS) at 6500 rpm (US market)

177 kW (240 PS) (Lancer Ralliart)

217 kW (295 PS) at 6500 rpm (European market)

Peak torque 422 N·m (311 ft·lbf) at 3500 rpm (Japanese market)

407 N·m (300 ft·lbf) at 4400 rpm (US market)

343 N·m from 2500 to 4725 rpm (353 N·m at 3000 rpm) (Lancer Ralliart)

366 N·m at 3500 rpm (European market)

Applications

 

* 2007 Mitsubishi Lancer Evolution

* 2008 Mitsubishi Lancer Ralliart (detuned)

 

Characteristics

 

Peak power and torque figures of 206 kW and 422 N·m are for Japanese market Lancer Evolution models[5] and figures of 217 kW and 407 N·m are for US market models.[6]

 

The 4B11T is the first engine in the Lancer Evolution series that uses a die-cast aluminum cylinder block versus the cast-iron block used in the previous turbocharged 4G63 engine that powered all previous models. The engine weight has been reduced by 12 kg (26 lb) compared to the 4G63, even with the addition of a timing chain instead of a belt and MIVEC continuous variable valve timing on both the intake and exhaust camshafts (the 4G63 had MIVEC valve timing & lift switching type on the intake only). A revised turbocharger offers up to 20-percent quicker response at lower engine speeds compared to previous 4G63. The 4B11T offers a broader torque curve, producing more torque than the 4G63 at all engine speeds, helped by the engine's square bore and stroke design (both measure 86.0 mm). Redline starts at 7,000 rpm, with a fuel cutout at 7,600 rpm to protect the engine.[6]

 

A semi-closed deck structure, an integrated ladder frame and four-bolt main bearing caps contribute to engine strength, durability and lower NVH levels. Unlike the 4G63, the 4B11T does not use a balancer shaft. The semi-floating pistons of the 4G63 have been replaced with a fully floating pistons for the 4B11T. Aluminum is also used for the timing chain case and cylinder head cover. The engine features an electronically controlled throttle, an isometric short port aluminum intake manifold and the stainless steel exhaust manifold is positioned at the rear of the engine. The use of a direct-acting valvetrain eliminates the need of the roller rocker arm configuration previously used in the 4G63. The 4B11T features built-up hollow camshafts and its valve stem seals are integrated with the spring seats. The internal components of the 4B11T engine have been reinforced to withstand high levels of boost.[6]