The Authoritative Galant VR-4 Resource

Join the best E39A 1991-1992 Mitsubishi Galant VR-4 community and document your GVR4 journey.

  • Software Upgraded - Reset Your Password to Login
    In order to log in after the forum software change, you need to reset your password. If you don't have access to the email address you used to register your GVR4.org account, you won't be able to reset your password. In that case, follow the instructions here to regain access to the forum.

Why remove the balance shafts?

so here is my two cents on balance shaft removal...Don't do it its not worth it...I work at Mitsubishi and have seen too many things go wrong when you remove the shafts. Think about it this way...when the engineers designed the engine they put them in there for a reason...If they were not necessary they would not have spent the money on them. Engines are balanced primarily for high r.p.m.s...so when you approach anything over 6 grand and you got mods your pushing it to the limits..you want all the balance you can get to eliminate vibrations. the extra 10-20 horse some people say you can get is bogus when your engine blows up...lol i've seen it happen. Now you can argue with me but do your best! again engineers aren't stupid...and they get paid to save money!
 

powerplay

Well-known member
It is not a question of additional horsepower. The balance shafts have two failure modes that take out at least the valves and possibly more. The belt brakes and takes out the timing belt and the bearings seize and cause the same thing. It is a fact and it happens. The balance shafts were put in the engine to reduce vibration. For what was anticipated to be an upscale buyer, who wanted the feel of a smoother bigger engine. Simply for comfort. If you chose to leave them in place, the belt should be changed regularly and the bearings are changed which requires the removal anyway. My engine had 138K on it when I removed mine and the bearing were in very bad shape. I was lucky and took them out before they spun. It is up to each owner what they want to do to their car. I am very happy I chose to removed them.
 

Engineers get paid to do what they are told, just like the rest of the world.
That being said, the "discerning" buyer of a quasi luxury sedan such as the VR4 would throw a fit if the engine did not run as vibration free and smooth as possible. The factory could balance all the internals within a few grams of each other and make the motor butter smooth, but this ain't no Bugatti with a 6 figure price tag.
That being said, car manufactures are run by bean counters not engineers, so when they say "Make the engine as smooth as possible as cheap as you are practically able to do" The Engineers step and say "Otay Boss!" Now of course that is way over simplified, but you get the picture. /ubbthreads/images/graemlins/wink.gif
I have owned more than one 4 banger that did not have a balance shaft anywhere near it when they built it, and those motors could spin to 10 grand IF built properly and balanced properly.
If you can eliminate the balance shafts and remove the possibility of catastrophic belt failure why not do it? I personally am not going to spin my street car past 7K. Most camshafts and turbo combos are out of breath by then for a street car.
A race car should be precision balanced IMHO anyway just due to the fact you plan on beating on it and spinning the car hard.
Now these comments are just mine,and what do I know? I'm just a dumb public servant /ubbthreads/images/graemlins/ooo.gif
 

quasimondo

Well-known member
Maybe you saw the Sport Compact car issue which featured a Galant VR-4, Mk3 Supra, and a few other old cars versus an Evo and STi. Maybe you saw the article where Daryl Samson's Galant blew the motor twice. What's not in the article is Daryl's explaination that the reason his motor went is because of the balance shafts. The first time around, it took out his oil pump, and the second time around, the leftover debris took out the bearings. It's not a matter of freeing up horsepower when the internal balance shafts are removed, it's a matter of simplifying maintenance and having one less thing to worry about with these engines.

Scroll down and look for the post under 'vr4underboost'

I mean no disrespect when I say this, but the fact that you're a Mitsu tech means nothing except for the possiblity that you might be able to hook us up with a discount for parts. I've seen my fair share of dealership techs who didn't even think the 1st generation Eclipse was all-wheel-drive, and I'm sure they had no clue that there was another VR-4 other than the 3000GT, and there's more than a handful of members here who were told that there was no such vehicle by a tech until they were brought outside and shown one.

Having said all of that, the elimination of the counter-rotating balance shafts from these engines is not a new concept, nor is it an experimental one. It's a modification that's recommended whether you have a big turbo, big injectors, and a big fuel pump or you're just puttering around with a 16G and a boost controller.

But, being the free country that it is, it's your car, you can do what you want, leave it in, take it out, makes no difference to me. Just please don't cry to us when the balance shaft belt breaks and gets jammed up in the timing belt, or when the bearings for the rear shaft sieze, lock up the oil pump, and take your engine out.
 
Last edited:

Ok maybe I should have said "Balanced as to make the vibrations nearly imperceptible" Vibrations won't destroy the engine, flying parts from destroyed oil pumps, or broken belts taking out other belts destroy engines.
I still think a properly balanced engine having a balance shaft, vs. utilizing one is a no brainer. If I want silky smooth, I'd own a Lexus. /ubbthreads/images/graemlins/rofl.gif
 

Years ago and 16 valves etc later. I learned the hard way to eliminate the balance shafts. /ubbthreads/images/graemlins/frown.gif


Wendy
 

jepherz

Staff member
I have no experience with removing the shafts, nor them going bad, but with all do respect, sickville, I have also had a fair number of experiences with the techs at Mitsu not knowing anything. Not to say what you do or don't know, but the people on this board deal with this ONE car, with this ONE motor and drivetrain and have seen the issues with it over and over again. There is no larger collection of knowledge on these cars other than maybe Japan and it would take a number of Mitsu techs' opinions/experiences to make me believe them over some of the most knowledgeable people on this board.

With that said, I don't think vibration is good for anything; your butt and your car included. Isn't the reason for the rubber in the crank pulley to dampen vibrations from reaching other accessories on the car? Even so, given the choice of an engine being destroyed vs. some of the other small possible effects on other parts of the car, I would opt for saving the motor first.
 

Im a die hard fan of taking chances..
I am the no BALANCE SHAFT, SOLID MOTOR MOUNT, UNDERDRIVE PULLEY QUEEN!!!! bwahahaha /ubbthreads/images/graemlins/grin.gif


Wendy
 

Mark LaVallee

Well-known member
And I'm a Mitsubishi tech and an ASE Master. In the last fifteen years I've put 500,000 miles on various 4g63s. I've not had the misfortune of having a balance shaft belt let go on one of mine, but I've seen it at least a dozen times. Causing a complete failure. Which is enough to convince me that when I build 581's new motor there's one feature that will be relocated to the circular file. A precision balancing job will be included. I'll live with the slight additional vibration. I didn't buy a Mitsubishi looking for refinement. I'll drive my girlfriend's 4.0 S Type Jaguar if I want refinement.
 

Street Surgeon

Well-known member
Quote:
Im a die hard fan of taking chances..
I am the no BALANCE SHAFT, SOLID MOTOR MOUNT, UNDERDRIVE PULLEY QUEEN!!!! bwahahaha /ubbthreads/images/graemlins/grin.gif


Wendy



No, if you were the "taking chances" queen, you would do that with an ACT2900pp on a 2G 7bolt /ubbthreads/images/graemlins/grin.gif
 
Last edited:

Well close enough..2900 with a 6 bolt no pwr steering or manual rack. /ubbthreads/images/graemlins/grin.gif


Wendy
 

Street!!!! dont put any ideas on her mind she will probably do it /ubbthreads/images/graemlins/wink.gif......lol thats what i call taking chances.....
 

Yes, vibration is bad for bushings and the frame itself, but I had the shafts out for 2.5 years and put down 20k miles. I had now problem with the engine getting destroid from unbalanced vibration. And after a awhile I got used to it anyhow.
 
Last edited by a moderator:

atc250r

Staff member
No amount of balancing will eliminate the vibrations that the balance shafts cancel out. They are NOT there to aid in the balancing of the rotating assembly. They are there to cancel out the normal harmonic vibrations that are inevitable in an in line 4 cylinder engine. They are only there to make the driver/passengers feel less vibration from the motor. Like Mark, I have seen plenty of BS belts broken during my 8 years as a Mitsu tech but NEVER seen a problem related to removing the shafts. The GVR4 I currently drive was purchased from the original owner after he had TWO motors spit the BS bearings out and destroy the motor. Unfortunately for him the local gas station that did the motor swap for him didn't know to remove them so it ended ruining his new motor. Another GVR4 I owned had a broken t-belt when I bought it, I fixed that and said "1000 miles on the new head and then I go in to remove the balance shafts". Unfortunately about 700 miles into it the BS bearings spun and wrecked all the bearings in the bottom end so I got to pull the trans, crank, and replace ALL the bearings in the bottom end. I will never own one of these cars with them in again and whenever I do a t-belt for someone I always recommend removing them. If not I take no responsibility for their engine's demise.

John
 

dsmtalontsi95

Well-known member
If you balance the bottom end, when you rebuild it, will that take care of ALL of the concern on both sides?

chance
 

atc250r

Staff member
No, the balancing of the rotating assembly (rods, pistons, crank, flywheel, crank pulley) has absolutely nothing to do with the vibration that the balance shafts are there to eliminate. They are purely for the comfort of the vehicle's occupants. Of course it is a good idea to balance the rotating assembly in any sort of performance application but these motors are pretty damn close right from the factory. FWIW mine isn't balanced, it sees 8000rpm a couple times a week, and has lived for 25,000 miles. When I build a good shortblock next year with aftermarket rods and pistons I will have it balanced.

John
 

CP

Well-known member
Think of it like this:

Have you ever been on a jet when they fire up the engines before takeoff? The drone/vibrations you hear at certain rpms as they build rpms are a result of the two engines being out of sinc. I've heard this at cruise as well, when the pilot doesn't have the throttles trimmed out exactly the same. This is the same type of hamonic effect you get without balance shafts, as the engine will vibrate at certain rpms...naturally.
 
Last edited:

speedyvr4

Well-known member
Wow.I've always been torn on this subject and you guys raise alot of good points.This is one of those things that if I ever have the engine out,i will do,untill then I'll keep changing the damm belt.my.02
 

atc250r

Staff member
Don't change the belt for the front one, just take it off and leave it off. Then you'll only have to worry about the bearings on the rear one failing and not both front, rear, and front belt.

John
 
Top