Quoting cheekychimp:
Mark,
I buy that and I realize that in most cases, owners of VR4s tend to modify their vehicles to make them significantly more powerful than stock, but are there that many recorded instances of catastrophic balance shaft failure? And technically, weren't thousands of VR4 and DSM owners using them without problems before they started modifying the engines?
Again I'm not saying you are wrong, I'm just trying to get a grip on how many instances of failure we are talking about in terms of percentages and whether failure was attributable to poor design or just stressing the engine way beyond the manufacturer's recommendations. If the failure was noticeable at high rpms for example, wouldn't there be a case for saying that the shafts are perfectly safe in a car with a stock red line?
Paul.
Edit: Personally, I had the balance shafts removed during my 'ultimate' Galant build but left them in on the stock daily driver car. I do think the stock car is smoother, but then again it's kind of hard to tell because (a) I've done other things to the project car which obviously increase vibration anyway (like fitting harder polyurethane engine mounts) and (b) I've done very little fettling and tuning on the project car whilst I've had a ton of work done on the daily driver getting it to run nicely!
Paul, i have to chime in on this, because i just bought a running and driving 1g with a bad balance shaft bearing. it did enough damage to destroy the bearings, oil pump, throw metal everywhere, just cause a real mess. the lower shaft bearing i found in the oil pan, and the one closest to the case had welded itself to the upper shaft. the owner originally said the car had something "scored in the head" as his CL ad stated. i went to see the car, listened to it, and heard what he had to say. sounded like a stuck lifter for about 2 seconds, then it was quiet. he said he ran it, drove it around, etc, and it never made any more noise than upon initial start up.
mind you, this car is bone stock. no modifications at all, just maintenance. down to the heatshields, MAF silencer and airbox, and the darth vader BOV cap. nobody screwed with this thing, at all. the car has 150k, and judging by the rest of the car, nobody really beat on it. i think about how much damage this caused, saying that to save this engine will cost a very good amount of cleaning everything thoroughly, along with a set of bearings, new oil pump, and very possibly a crank, including all the gaskets and everything else. so a full rebuild, basically.
its just not worth it.
you want comfort, don't put poly mounts in your car. get nice new rubber ones. don't put cams in it. and turn the idle up a little to combat the vibrations. ditch the balance shafts, and take 3 bearings out of the equation that could potentially spin and damage the rest of your engine. not to mention removing the risk of that belt somehow letting go, and causing the timing belt to jump time. i just see the balance shaft removal as a necessary procedure at this point as long as the engine is apart. its added insurance and peace of mind, plain and simple.