Learn Me-Balance Shaft Removal

I've been looking into maintenance and modifications to do to my SRT-4 Engine while it's out of the car to get it ready for locost duty. One thing I have come across is removal of the balance shaft assembly. On this engine the assembly is driven by a chain and the plastic chain tensioners are known to fail catastrophically on heavily modified engines. I "only" ever plan on making around 400 HP, which is around the threshold where it is recommended to remove the assembly. Removal takes out about 20 lbs, reduces rotating mass, and allows 2 quarts of additional oil capacity which all seem like very good things, even at near stock power levels.

Supposedly removal of the balance shafts only adds minor vibrations at idle and low RPMs, and has no impact on engine life. The engineer in me is skeptical that Dodge would include this heavy, complex, and expensive assembly in a "rough around the edges" performace car like the SRT-4 if some minor vibrations at idle were the only down-side. What, if anything, am I missing?

Removal of the counterbalancer in Suzuki GSXR1300R Hayabusa engines used in cars is S.O.P.

The baffled oil pan I use came w/ a block-off plate and instructions to TIG weld the oil hole shut in the balancer shaft. I made a threaded plug to go in the end so it's reversable.

In any case, the engine is rigidly mounted to the chassis about a foot behind the fiberglass seat - there's a little buzz, but at speed, being in the car is like Niagara Falls in a barrel of methamphetamine crazed weasels, so you don't so much notice.

The balance shaft(s) intent is for reducing the vibrations inherent with a long stroke four cylinder. When the crank is at 90B/ATDC, the pistons are more than halfway down in the bores due to the angle of the connecting rod, and this uneven acceleration, in unison, causes a righteous shake.

It's countered sometimes somewhat by how the crank speeds up around the TDC mark because the reciprocating loading momentarily stops for all pistons.

Why did Chrysler spend the money? Because they're trying to cut down on NVH so that they can sell cars.

I removed the balance shafts in mine - never really noticed anything especially untoward, but I was running 2 1/2" exhaust with a cat, no muffler. YMMV.

The balance shaft was removed in my Sentra as part of the turbo build. However, if I had to do it over again, I'd leave it in. Between that and the solid urethane motor mounts, there is quite a bit of vibration at idle speed.

I find balance shafts to be amusing- Once, a Volvo 16 valve red block showed up for timing belt change. I noticed that it seemed to be one of the nicest running ones I had encountered, The balance shaft belt had come off, and was laying in a pile at the bottom of the cover. After installing the belts properly, it was back to its shakey old self again.

I removed the shafts from a 2.6 Mitsu once, and found it to run better as well.

I had a 2.4-swapped Neon in which we cut the balance shaft chain because of clearance issues, but left it in place rather than figure out how to plug it up. The car did not run annoyingly rougher, though it was noticeable at idle.

Remember that your boosted 2.4 was originally designed for the PT Cruiser, which was designed for people who aren't all that tolerant of shaky cars.

being in the car is like Niagara Falls in a barrel of methamphetamine crazed weasels

I don't now why but the picture in my mind at the moment is priceless.

Hahaha..... Shaft removal.

motomoron wrote: ...being in the car is like Niagara Falls in a barrel of methamphetamine crazed weasels.

That needs to go in a GRM t-shirt/hat/fender-cover/whatever!!!

Is the case acting like a block girdle?

Balance shaft removal in the 2.3L Duratec used in the Focus is usually the first modification people do.