Engine balancing [Merged 6-7]

[Stock90GSXT]

Okay. I need some advice. I removed the balance shafts out of my 6bolt. I have heard two different sides.

1. The engine is'nt balance w/o those, so get the Rods, Pistons, and Crank,flywheel balanced

2. The engine is already balance w/o the balance shafts, they were just there to remove vibration so customers would'nt complain.

I was thinking. If the engine was vibrating. then its not balanced. I need imput from the people who have had experiance in removing the balance shafts. Is it worth it to balance the bottom end. Or is it a waste of money?. Keep in mind. I will be changing the perimeters by installing 95+ pistons on my 1g Rods. I know anytime you change stuff like that its recommended to balance the engine.

 

[MarsaGSX]

Venca, you can try FFWD. Look at the link below (scroll all the way down to the bottom):




http://www.ffwdconnection.com/20new.shtml




I'm not sure if they offer this to the public, or if they just use this on the engines they build. But you can give it a shot. A simple phone call or email will do.

hey,
Thanks...Sent email to Darren at FFWD,and get fast answer

BTW what about 4G63 as Inline 4 and balancing whole rotary assy..
Darren told me its the point of all pistons and rods need same weight, told me to balance only crank...

Venca

 

[Spln_Hrd]

I have noticed I don't see many people considering engine balancing as a modification, and I was just curious if this is because it is something people feel is not important or what the deal is.

 

[TSIfreek]

Its not a modification is something that is done while the machine work is performed. Its not an option to me. Your bearings will thank you for it.

 

[JWoodley]

I guess it all depends on yours goals for the car and how you'll be driving it. Personally, I know how I drive and it's worth the extra cash to do it the right way.

 

[Defiant]

Yeah, it's not a mod, it's routine. If your machinist even asks whether you want to, you have the wrong shop.

 

[paper_clip_boy]

This is something that will kill engines so quickly. Especially if your running a 2.3L or any engine with an Underdrive Crank pulley. Bearing wear will result much quicker.

Im running my 2.3L without balance shafts and with an Underdrive pulley but everything has been balanced for the setup so I should be OK, It would be better if I ran atleast a stock pulley or a Fluidamper, but I'll take a chance. Also on the Strokers, It would be even more recommended to run a Main Girdle Brace to prevent event further fretting of the bearings in an unbalanced engine.

 

[Spln_Hrd]

Thanks for the votes guys!

I am intending on doing mine, but I was just curious what everyone else does.

 

[AL92]

I have a 2.4. I used stock crank polished ,wiseco pistons,crower rods. I have fluidampr balancer.
I didn't get it balanced. I read you have to balance with flywheel, clutch on their. What happens if change make of clutch. Even same make of clutch maybe are out a bit?

I just had engine problem at 4500 miles. I am not sure yet if its spun bearing, belt jumped time. I will be taking close look in next few days. I used acl coated bearings.
Shop put together bottom end I did the rest.

I plan on a few changes if the engine comes out and pretty sure its going to have to.
This time am going with eagle forged crank and this time want to balance things. But is it enough to zero balance things if that is the correct term. Just balance the crank,rods and pistons and then zero balance the flywheels or do I have to put the flywheel on the crank with the balancer? I might try a few different flywheels.Heck might even try ati balancer.
So what should I do this time around.
Also I took out balance shafts and ported my oil pump relief. Wondering if maybe ported it out too much. What oil pressure should be good with my no balance shaft motor. The 2.4 has no oil squirters installed.

I had very minor vibration at idle but have poly inserts front and back ,stock mounts on the sides. I did find lots of bolts kept loosing up like exhaust bolts, etc.

I also had some overheating issues when engine was just done with factory mits therm sticking on me. I shut car down when it happened right away and towed it home. Engine seemed to be running aces for all its previous 4500 miles .I don't think detonated it to pieces was running pretty low timing and only 20psi. Guess will know more after dissection but it might not be till winter .Too many projects to worry about this car right now.

 

[SnowBird]

You have to balance the crank, flywheel, pressure plate, and harmonic balancer all seperately. If you change make of flywheel/clutch it doesnt matter, most reputable brands already come pre-balanced and it shouldnt be an issue. I have an XACT flywheel, SBR clutch and when I built my engine all I got balanced was my crank since I bought a new HB.

 

[Rabbi]

can anyone explain what balancing the engine internally means and why its needed?

Ive searched with no results.


thanks guys

 

[Defiant]

Essentially, same as a tire. Google "engine balancing".

 

[99gst_racer]

So, are all of you guys doing a neutral balance, or are you overbalancing?

 

[steve]

So, are all of you guys doing a neutral balance, or are you overbalancing?

Overbalance? The stuff is either balanced or it's not.
I understand static and dynamic balancing but what is overbalance?

Steve

 

[steel_3d]

I believe overbalancing is something that applies to v8 (and probably v-anything) engines. I'm sure you'll find out more about the term if you search.

In short, no. Every component is balanced individually, and it works out fine for our straight up and down crank configuration.

 

[Elvenhome21]

overbalancing is used in drag racing or circletrack racing. its when the bob weights on the crank are made heavier than the rod and piston. It helps with inertia, in a circle track motor 3% overbalance is ok, drag racing I have seen upwards of 10%. A engine that is run on the street you want a neutral balance, other wise its like just removing one balnce shaft and leaving the other alone. (shakes like a bi***)

 

[steel_3d]

I don't know if this has been mentioned before, but Balancing the pistons and rods should only mean juggling components until the total weight in each cylinder is as close as possible. I got mine within about a half gram tolerance (if you search long enough on ebay you can find nice scales with .1g accuracy and 1000g max for not much money - you can find all kinds of uses for it later ; also, most shops only have scales with 1g accuracy). Granted, this is not perfect dynamic balance, but it's probably as close as we need to get it.

You can get a perfect dynamic balance if you match the weights of the big and small ends of the rods, and the weights of the piston assemblies. The issue is that if you take material off the small end you may weaken it by removing too much material and/or creating stress risers, which in my opinion is not worth the risk. If I were to do it I'd do it very carefuly and with thought, not leave it up to joe blow machinist to take a grinder to it and call it a day. Even taking material off the big end can be iffy. In pistons there's usually enough material around the pin boss to not matter too much.

We also don't match counterweights to reciprocating mass. Whether we should or if it's even possible is a different story.

 

[steel_3d]

http://www.rpmmachine.com/engine-balancing.shtml

"With inline four and six cylinder engines, and flat horizontally opposed fours and sixes (like Porsche and Subaru), all pistons move back and forth in the same plane and are typically phased 180° apart so crankshaft counterweights are not needed to balance the reciprocating components. Balance can be achieved by carefully weighing all the pistons, rods, wrist pins, rings and bearings, then equalizing them to the lightest weight. "

I believe the purpose of the counterweights on our cranks is to equalize bending forces on the crank.

Here's an article that talks about overbalancing and all that bobweight business for v engines: http://www.automotiverebuilder.com/ar/eb40634.htm.

 

[steve]

http://www.rpmmachine.com/engine-balancing.shtml
Here's an article that talks about overbalancing and all that bobweight business for v engines: http://www.automotiverebuilder.com/ar/eb40634.htm.

Thank you for those links.

Steve

 

[RichCaccese]

I've come to the point in my motor build when I am going to decide to send everything in the bottom end + clutch to get balanced, or just go ahead with the install. Talking to friends on "both sides" some work for performance shops, others are strictly DIYers in their garages/driveways, I'm (surprisingly) coming up with mixed answers.

Bascialy, my goal is 500whp. I plan on (have purchased) building a weisco/eagle 2.0, with a full Crower , lightly ported head on 272's. I plan on topping it off with an FP3565.

Some people have told me that it's really not worth a whole lot on an inline-4, that there isn't much to balance, power output won't be anywhere near what it can do with a V6 or V8, and that I am just wasting my money, that they are just really going to be able to balance the flywheel, because there it really nothing more.

Initially, I wasn't really planning on doing this for huge power potential, more to safely be able to rev the car to it's new potential (8k-8.5k?) Others have said exactly that, if I plan on revving that 2.0 out, then it should be unquestionably done.

I am just looking for some more feedback and suggestions. Thanks in advance.

 

[Defiant]

Some people have told me that it's really not worth a whole lot on an inline-4, that there isn't much to balance, power output won't be anywhere near what it can do with a V6 or V8, and that I am just wasting my money, that they are just really going to be able to balance the flywheel, because there it really nothing more.

In my opinion, those people are ignorant.

Always balance an engine. Regardless of the layout.

Merged to Balancing thread.

 

[ChiGGz]

Do I have to balance a new flywheel with an old (but good) clutch? I recently had a problem where a loose bolt ate up my flywheel so I bought an ACT X-act flywheel and using my old SBR3500 clutch.

Do I need to balance the two together? Or am I good to go.

 

[silver bullit]

No....

 

[nfernotalon]

Nah, throw that bi*** in.

 

[turbodsm_125]

nah, but i would consider getting the flywheel reconditioned. It will increase the life of the cluthc as it has a smooth surface to contact with and wont tear it up.

 

[TSiAWD666]

What does it mean to have a flywheel "reconditioned"?