Balance Shaft Elimination cons

[Cobalt60]

Almost every time I see advice on increasing performance of the G54B, someone either recommends removing the balance shafts or states that they have done it. I would like to know what the cons to removing the balance shafts are. My understanding is that they reduce engine vibration, vibration which would otherwise cause wear. So some say that removing them increases reliability, but I can see how the opposite could be true.

 

I plan on doing many upgrades to my car and its G54B, but I am pretty sure I want to keep the balance shafts. Especially on the biggest 4 cylinder I am aware of being put into a car other than a Porsche.

 

-Chris P

[Technology]

More vibration at certain RPMs. Actually a BSE does increase reliability from the standpoint that you don't have extra chains to fail and bearing surfaces to shave metal into the pan.

 

Everybody I know removed them and it really doesn't make that much of a difference. Nobody's ever dyno'd a car with BSE being the only mod.

[Dcrasta]

Pro's :

 

1:Less moving parts(Chains-shafts-) reducing inertia and mass in the motor. This allows a more-free revving responsive engine.(And increased reliability)

2:Less oil pressure being diverted away from the head and bearings

3:Higher oil pressure across the board

4:Cheap (complete kits less than 70 bucks-elcheapo kits for about 30)

5:No more adjusting of the balancer-shaft / oil pump chain

 

Con's :

 

1: **Unless you balance the rotating assembly** depending on your motor, you *May* experience more vibration/roughness after this mod.

2:-Voids- any rebuilder's warranty.

3: Requires removal of the oil pump to install.

[TopDawg_43]

So some say that removing them increases reliability, but I can see how the opposite could be true.

 

I plan on doing many upgrades to my car and its G54B, but I am pretty sure I want to keep the balance shafts. Especially on the biggest 4 cylinder I am aware of being put into a car other than a Porsche.

 

-Chris P

 

It's 100% true that it will increase the reliability of the engine. The timing chain that turns the BS also turns the oil pump. That chain is about a 2' long. Remove the BS and that chain shrinks to about 6". With the BS, you have giudes(that can and will break), that have to be adjusted. Also when you remove the BS you get more oil to you crank, because you block off the oil passage that went to the BS. And last but not least, it's less rotational mass. Less weight that the motor has to spin.

 

It will be very hard to dispute any of those facts. As long as you get your crank balanced, your engine will run smoother. There's less lumpyness at idles, revs easier, and runs better. Oh, and the bearings on a BS will go out on you. I had that happen once, I was lucky enough to save that engine. Remember, when the BS are not turning the oil pump is not spinning.

 

If you build an engine with the BS, they will be the bottle-neck in your build.

[Tim_C.]

I agree that removing them is the better choice for the large majority of used engines out there. Even though balancing the engine internals has nothing to do with removing the choppyness from the 2 up 2 down piston movement, it does smooth out the vibrations considerably (balancing). Mine is smooth as silk with no shafts. But then I had to run a large roller cam with solid steel motor mounts! LOL!

 

The oiling to the upper shaft is the first passage to clog from normal sludge. Used StarQuest 2.6L's are abused beyond belief. It is very hard to find one that isn't abused, and well kept. Even if it is, how do you know? Chances are much higher now-a-days that there will be a problem with the shafts that is terminal to the entire engine. The safest thing is to pull them out and give the engine a much better chance at survival.

 

If you are a purist who wants to keep the shafts, and some of us are, you should do a full engine rebuild including replacing the shaft bearings, and polish the shaft journals. Assemble the engine with everything super clean and dry except for lube.

[Technology]

Yeah, It is possible to rebuild the engine with them in for a stock-like feeling, but you can get pretty close without them.

[NightRider2.0]

Once the BSE is completed, would you have to take the car to a shop to have it balanced?

 

Thats the only part I'm confused on is where to take it.

[Dcrasta]

A full balance job requires the you to remove and give to the machinist -

 

Crank

Rods W/ Pistons (And rod caps)

Crankshaft Pulley

Flywheel

CLutch Pressureplate (usually optional)

 

A lot of people do not get the engines rebalanced if they are just installing the BSE in the car. IF the engine is out of the car its normal to get those things re-balanced anyway.

[Dad]

You don't have to balance the crank, rods with BSE

 

Highly suggested to do so if the engine is out. But many are eliminated while engine is still in the car.

 

Dad

[TexasQuest]

Great info guys.

[NightRider2.0]

Thanks guys!!!!

 

I have been looking at BSE Kits and timing kits.

 

there seems to be a three piece and a six piece. which is suggested?

 

I'm going to be changing out the oil pump and do the BSE at the same time.

 

One more question, do you have to pull your motor to do a timing chain?

[TainterRacing]

One more question, do you have to pull your motor to do a timing chain?

 

no you dont have to but it can be a pain to get the lower oil pump bolt out. I would remove the radiator and it makes it alot ez to get to the front of the car.

[vbrad511]

Like Tainter said, pull the radiator. Give yourslef plenty of room to work and things will be fine. I did my BSEK on my 88 a while back, took my time, ran for parts, ate, got sidetracked, etc... and it was all back together in a weekend. The hardest part of the job was scraping the 20 year old oil pan gasket off the bottom of the block. Yes, you need to drop the pan. Yes, you should change the timing chain and guides while you're there too. You'll be amazed at the amount of powdered guide material that's accumulated in your oil pan.

Since the BSEK I've noticed better oil pressure, a snappier more responsive throttle (which is probably due to swapping out the old timing chain), and just a little bit of harmonic vibration between 2600 and 2800 rpms, but it's very slight. Would I do it again? Yes, and sooner.

Go through these posts;

 

http://starquest.i-x.net/viewtopic.php?t=1...c3472dbb0f2d9b8

 

http://starquest.i-x.net/viewtopic.php?t=944

 

The info and pics will help immensely.

[Dcrasta]

One more question, do you have to pull your motor to do a timing chain?

 

 

No but you should remove the oil pan to get to the bolts for the oil pump pickup. If you try to wiggle it out you may bend the pickup tube. You can get the pan out by removing one side of the front sway bar end link, and the sway bar bushing mounts, and just pull the sway bar to the front. Remove the 10-15 bolts for the oil pan, and move the pan forward and down. That way you have good access to the bolts supporting the oil pan pickup. Replace the oil pump pickup o-ring with the factory part, and do not use RTV on the oil pump gasket (I use gasket shellac).

 

After you have the motor back together crank it (no spark plugs, injectors disconnected) until you see your oilpressure -bumping- on the gauge. (this is the easiest way I know to prime the pump). Do the cranking in 20-second spurts. Should sound like a electric motor ...

.

[JustPaus_88TSi]

Just for info's sake, I did the BSE when I rebuilt my motor. I kept the standard bore on the cylinder walls and the rod/main bearings because they were well within spec. I replaced the pistons because the groves for the rings were close to being out of spec and they deviated too much for my liking.

 

The only machine work I had done was to press the new pistons on to the rods. Slapped it all together, fired it up and I haven't noticed any vibrations. I did not have the rotating assembly balanced with the new pistons and BSE.

[Fuze]

I have had motors with and without, there's no rule. Some stock motors vibrate at some RPM's, some without the balance shafts will also. I always eliminated them when I did a rebuild, but since it was all apart I had the rotating assembly balanced. The pro's are faster revving and way less metal flying around in there.

If you've ever seen the shaft bearing fail, or the shaft seize and have the chain shear the gear off the end, you'll take 'em out every time!

[mikec]

The balance shafts do not compensate for mis-matched pistons+rods+crank parts (the rotating assembly). Any inline 4 cylinder engine suffers from "harmonic vibration" because while some parts are moving left, some are moving right and those parts are on opposite sides of the center of gravity. It's inherent in the physical layout of a 4 cylinder inline engine. The resulting imbalance happens at TWICE the crankshaft RPMs. Balancing the pistons, rods, etc. (i.e. making sure all pistons have the same weight, all rods have the same weight, and that the crankshaft center of gravity is perfectly centered along the shaft) will not remove this "second order" vibration... balancing removes "first order" vibrations just like adding those (ugly) weights to your wheel+tires to balance them.

 

To counter the "second order" vibrations, Mitsu engineers developed the "Silent Shaft" system - what we call the balance shafts. These are shafts with chunks taken out of them (i.e. they're nowhere near balanced about their rotation axis/centerline) and they're driven by a chain at TWICE the crankshaft RPMs. Because they're not balanced about their own centerlines, they vibrate horribly... but because they spin at twice the crankshaft RPMs, their vibration is perfectly in sync with the crankshaft/rod/piston's second order vibrations and they cancel!

 

Removing the balance shafts allows the second order vibrations to return... as I noted before, ALL INLINE 4 CYL engines suffer these vibrations (unless they add some sort of balance shaft like Mitsu, Porsche and some Hondas). The larger the displacement, the worse the vibration. The vast majority of 4 cyl motors don't have balance shafts and they last for many thousands of miles, right? So eliminating the balance shafts is not going to kill a 2.6 engine. Without the balance shafts, there is more oil pressure and volume for the rest of the engine which helps increase durability.

 

Since the balance shafts spin at twice the crankshaft RPMs, the balance shaft bearings wear the fastest on a 2.6 engine. Combine that with the fact that one of the shafts has bearings fairly high on the block (lower oil feed pressure) and it's easy to see why the bearings on the balance shafts are typically the first to wear out on a 2.6 engine... and when they wear out, the balance shaft suddenly jams and won't turn. Well, as was aready noted by another person, the chain that drives the balance shafts also drives your oil pump. When the balance shaft jams, the oil pump is "jammed" too and suddenly the engine has no oil pressure... the whole thing gets demolished pretty quickly. The balance shaft elimination kit removes this catastrophic failure possibility.

 

Quite a few folks have done the BSE kit without balancing their engines. Most don't feel much, if any, change; others notice a slight buzzing in the shift lever around 2500 to 3000 RPMs - that's the second order harmonic vibrations "resonating" with the mass of the engine+tranny and the springyness+damping of the motor mounts.

 

Balancing requires taking the engine out of the car and totally apart. It takes sensitive weight scales to measure each piston to identify the lightest one... then the others are filed/machined on certain "sacrificial spots" to lighten them to that same weight. This is repeated for the rods too. The crank is "spun balanced" like a tire; small sections of metal are ground off as needed to make it balanced.

 

mike c.

[NightRider2.0]

you're the einstein(sp?) of conquests.lol

 

Thank you guys for all the help.

 

Which timing kit is suggested as well?

[Dad]

6 piece and a cam timing will do it.

 

add pan gasket, timing gaskets, valve cover gaskets.

oil pump gasket and o/ring and this phone #

 

330-505-1804

 

Just ask for Dad ( Randy)

 

or enginemac1@aol.com

 

or PM me.

 

It's that simple!

 

Dad

[Shelby]

Dad's the only one stop shop you will find, auto parts stores can't get all the parts need'd with out buying a lot of not need'd gasket sets

[NightRider2.0]

I've priced the 6 piece BSEK.

 

New OEM Oil Pump.

and the complete camshaft timing kit that goes with the BSEK.

 

= 256.93

[Dad]

I've priced the 6 piece BSEK.

 

New OEM Oil Pump.

and the complete camshaft timing kit that goes with the BSEK.

 

= 256.93

 

 

Whats wrong with your oil pump?

 

Dad

[Caliber308]

Once the BSE is completed, would you have to take the car to a shop to have it balanced?

 

Thats the only part I'm confused on is where to take it.

 

Not the car, the rotating assembly in the motor. That requires that the engine be taken completely apart, and all rotating parts be balanced. You do that during the engine rebuilding process. When I did the BSE on my car (before the engine rebuild) I experienced a little vibration, or as some like to call it harmonics on acceleration in third gear. Other than that, no problems. After the rebuild and rotating assembly balancing, no vibration or harmonics what so ever.

 

CALIBER 308

Edited October 17, 2008 by Caliber308

[NightRider2.0]

Whats wrong with your oil pump?

 

Dad

 

nothing is wrong with it.

 

But, I thought it would be a good idea to replace it seeing how the car is so old?

[Tim_C.]

I have done a couple of BS Elim jobs with the engine still in the car. Definitely remove the oil pan. I did get a fairly nasty harmonic like Mike C. mentioned at about 3800 - 4100RPM on both cars. One is auto. It lasts for about 200 - 300 RPM, but it seems like a long time unless you are accellerating very fast because at that RPM, you don't run through 300 RPM very fast with normal driving. However, above 4,000 is only needed for highway passing in normal driving too.

 

I also did a bare-bones rebuild on an engine with no balancing and did not put the shafts back in it. That engine has no noticeable vibration like the other 2.