I've noticed several threads/magazine articles regarding removal of balance shafts to increase HP. It's covered in the new Turbo and I was just wondering why car companies include them in the first place. I know it's supposed to smooth out the idle but I've yet to hear any complaints form those who have removed them.

 

They act as harmonic blanacers......protect the engine from dangerous vibrations that can prematurly wear out bearings, rings, seals and the oil pump.

 

If balance shafts increase ring wear i`ll eat my dirty shorts with no butter or ketchup....

as for wearing out bearings faster i can`t really see that because those shafts are connected to a belt that adds drag to the crank, so it`s added resistance to a crank so how can added resistance, decrease bearing waer ??? hmmm.... seals are seals, rotating objects wear then no harmonics.. and every seal has a spring inside to take/give stress to apply presure for the seal... no applicable in this aspect... as for the oilpump tha`ts why all the hardcore racers upgrade to toda or prodrive usa (like me) so with a prodrive unit and new main and connecting rod bearings... BALANCE SHAFTS, if you want to find them, they are in the bottom of the ocean i live next to... for the added vibration, hell i don`t the GF will mind HAHAHAHAHAAH

-G

 

balancer shafts smooth out harmonics. yes the do increase engine life. no they are not nessecary in a performance motor


[Modified by TREVER, 5:31 PM 1/13/2003]

 

Here's the thing - the balance shafts travel at twice the speed of the crank. You think that's added drag? Once they're in motion, they have a pretty good chance of staying in motion...

They ARE there to help prevent wear and vibrations.

 

I`ll see if that`s true... i have a completely new bottom end, Crower pro billet rods, type-s pistons, prodrive gear, all new bearings and seals etc. i`m running the motor one summer than tearing it down so i`ll be able to calculate miliage and wear about this myth.... proper balancing, assembly and taking care of a motor can overcome anything..

 

are balance shafts an H22A thing?? ive built B-series and dont know what the hell a balance shaft is....... and yes i feel really stupid asking this question, but i gotta learn this stuff.

 

balance shaft IMO can be removed it you have your crank and the motor balanced.

If it's a stock engine or is a not balanced engine then it is needed to stop lil vibrations

 

I'm taking mine out. ****'em.

https://honda-tech.com/zerothread?id=310639

 

Edited.. not right.





[Modified by Nameless, 1:41 PM 1/14/2003]

 

i cant believe that that is actually what balance shafts are!

how can the engine spin without them?

it would be all off centred!

that is crazy! no balance shafts?

t..

 

no - wait, it would be just as centred, with 1/2 the weight?!?

hmmmm, this is too much for me,

just keep posting guys, dont mind me...

t..

 

balance shafts are not those lobes, those are crank counterweights (needed for primary order balance, meaning they offset the moving weight of the con rod/piston assembly on a cylinder by cylinder basis). A balance shaft is usually located to the side of the crankshaft (not usually in the same plane) and spins at twice crank speed to cancel out one of the 2nd order vibrations an inline 4 cylinder makes. It's a lot more important to have these as engine stroke increases, on small stroke 4 cylinders they become less critical for smoothness.


[Modified by texan, 10:35 PM 1/13/2003]

 

You're probably right, I think I've been confused with something.. where is it in the pic then? I need my automotive book, left it at school..

But as I remember, they show the pics of the lobes in the book, and they call them ballance shafts.

 

You can't see a balance shaft in that pic. Here's an example of a traditional balance shaft setup on an inline 4...


I've read that the new K24 in the CRV has the balance shaft setup merged into the oil pump drive system, so it wouldn't look like this.


[Modified by texan, 12:11 AM 1/14/2003]

 

Those crazy, Japanese engineers don't know how to make an engine last. Go ahead and toss that balance shaft. It's just extra weight!

On a more serious note, how do you just remove the shaft? Wouldn't you lose oil pressure form the open oil passages where the shaft used to be? Or do you just remove the belt?

By the way, does anyone know what company owned the original patent for the balance shaft?-----------------------> Briggs and Stratton. GM 6 cylinders still have Briggs&Stratton emblems on their balance shafts. Maybe thats why they run like lawn mowers.



[Modified by cjo_28, 7:12 PM 1/14/2003]

 

Balance shafts are NOT part of the crank. The things on the crank are counterweights. Balance shafts are other separate shafts inside the block. They're usually driven by the timing belt or sometimes a separate belt or chain.

The problem is... four-cylinder engines are inherently unbalanced. That's not a big problem with smaller four-cylinders. As displacement increases, the vibrations become stronger. This is why 2-liter or 2.2-liter engines (Accords, Preludes) have balance shafts, but B-series engines do not. Here's a quote with more info (taken from here http://www.geocities.com/gkurka2001/...h_engine_2.htm ):

An inline four cylinder need a pair of balancer shafts, driven by the engine and rotate in reverse direction, at twice the speed of the crank shaft. They locate in both sides of the engine, in the direction along crank axis. One of them is placed just above the crank shaft level, the other is far above. The vertical offset of the shafts induces a second order moment which is intended to counteract some of the gas torque fluctuation too. Counter weights on the balancer shafts will completely cancel the second order force, thus result in a silky-smooth rotation.

 

The counterweights on the crank that someone mistook for balance shafts are part of the crank, btw.... you go to automotive school ?

Balance shafts as mentioned are used in higher displacement engine to reduce vibration caused by big stroke 4 cyl engines. The pic above seems to be a B series, no balance shafts, plus the shafts are not in the crankcase anyway.

If you look, cars like the accord and Prelude have balance shafts (both 2.2L) and the new Sentra has them as well, checking in at 2.4L or so....truck motor that is no where square. These engines NEED balance shafts for longevity.

True, 'performance' motors may not need these shafts, but how many of the people that take out the shafts actually have 'performance' motors rather than just modded stock motors ? Unless you plan to rebuild sooner than later... taking out the balance shafts is just idiotic. I guess the Jap engineers with their vast R&D and engine building knowledge are just a bunch of dumbasses...

X2

 

The book I have shows the counterweights as balance shafts. Yes, I go to auto school and we have discussed it in class, I might have been sleeping (seriously). Can you tell me why the book says this? These are "Today's Technician" books..

Why does it show the counterweights as balance shafts? Is it just to give an idea of what they act as in a smaller displacement engine? It does not show a seperate shaft/s..

 

Well, I don't know why your book says that. The parts in the picture are the counter weights for the crank throws. The allow the crank stress relief at speed. They can be cut (knife-edged) to improve aerodynamics and lighten them for race purposes, but will weaken the crank in essence and throw off the balance, reciprocating assembly will need to be rebalanced.

Although this part of the crank provides it balance, they are not balance shafts (also notice, they are not even the shape of a 'shaft').

HTH


[Modified by X2BOARD, 10:17 PM 1/14/2003]

 

phew!

i thought that was pretty nuts!

i can honestly say i have never seen a balance shaft.

but now must ask, why none on the B20A or B21A? or even B20B?

probably cost?

t..

 

wow i feel a lot better. at first i thought i had left something out of my B18C, then i thought people were grinding off the crank counterweights. <whew> glad i didnt run out, tear my engine apart and grind away at my crank

 

yes, love will concore all...except phisics..lol jk..i dont even know what you guys are talkin about but keep talkin..im learning...

 

Balance shafts are worthless. DSM owners remove them all the time from 4g63's. They are there for nothing more than your ***. Old people, that buy cars, don't like the shakes. If you can deal with urathane inserts, removing the shafts is nothing.

I don't know if they sale kits for h22's but I imagine that they would. Kits usually consist of little balance shaft stubs, that replace the big ones, and block off bearings, to block oil passage to the balance shaft so you dont have **** oil pressure.

If I had removed mine earlier i wouldn't have trashed my engine in my eclipse, I threw a balance shaft bearing and the thing bounced around and trashed some pistons, and I lost oil pressure, and the shaft was spinning w/o a bearing making the motor overheat and make clunking sounds.

Basically, trash 'em, its worth it IMHO.

 

ok, guys, remember that the factory doesn't balance the engines, so, that's why the put the balance shaft. they use this cuz the cost of balancing every engines is higher than putting a balance shaft in there. IMO if you build your engine and balanced it, you can take the balancer shaft out, but it wouldn't hurt to leave it there.
The balancer shaft is not in your car so you don't feel the engine (well at least that's not the main idea) it kills small vibrations (the kind that you wouldn't feel are the main ones) so that the bearings doesn't have to handle them and wear faster.

In fact, i read once that balancing an engine makes it last 50% more than a normal engine. Perhaps the balancer works, but not as good as balancing the whole assembly.

And for the guy with the trashed 4G63 engine, your case was, perhaps, one in a million, do you know if that happened to someone else? i think not (not sure anyway)

Cliff notes: If you are building a race engine and every HP counts, take it out, but if this is a street engine and you want reliability it wouldn't hurt you to leave it there.