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2.3L - WITH balance shafts

tsitalon1

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Joined
Dec 29, 2010
Messages
309
Location
Montgomery Al
Hey guys,

After a great discussion with some of you I have decided that my future build will most likely be a 2.3L stroker with 9:1 compression mated to a Evo316g turbo or maybe a Borg Warner turbo. Discussion Here

Goals for this build are maximum torque across as much powerband as possible with 7k rpm limit. Should be a fun street car /ubbthreads/images/graemlins/smile.gif

Now for my problem:

I had a 2.3l from Magnus in the past. Loved the power (don't remember the CR), but hated the second hand harmonics that seem to vibrate every bolt on the car loose. This vibration was subtle in that you could barely feel it in cabin, but no sh*t - I was retightening bolts monthly or less. Yes I had a damper on it

I do not want this kind of vibration again! Reading the "To stroke or not" PDF file, I now know why I had vibration in that motor!

A lot of you guys are going to try to convince me that balance shafts are evil, power robbing, possibly engine grenading things. I hear you, but the 5 or so motors I built with BS's have survived over 50k miles with no issues at all. Please keep in mind these motors stay close to factory rev limits.

Have any of you (or any of you presently) had the balance shafts installed in their 2.3l stroker before? Do you feel any vibration or have any bolts loosening due to second hand harmonics?

Should I run 4g63 balance shafts or do I need to run 4g64 Balance shafts?

I plan to hopefully build this motor next year.
 

alansupra94

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Mar 3, 2010
Messages
1,909
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Wayne,NJ
Isn't the weight and distribution of everything in the engine's rotating assembly changing? How will you know that the stock balance shaft will in fact reduce vibrations?
 

EMX5636

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Jun 28, 2008
Messages
1,631
Location
Bucks County, PA
They are different part numbers between the 4G63 and the Galant DOHC 4G64. I would probably run the 4G64 ones because of the added crankshaft weight/throw. Then the only difference is piston pin height and bore. Neither of which should affect balance. I'm in the "who needs them" category other than that though. Sorry.
 

cheekychimp

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Apr 19, 2004
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East Sussex, U.K.
James,

First off I think that will be one very fun combination and should provide fast enough spool without running out of steam too quick.

Second, I have a confession to make. My other car is a 2.3 litre stroker built by FFWD. Mine has the balance shafts removed but I didn't have any real vibration.


Paul
 

raptorWagon

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May 17, 2007
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2,827
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Oak Harbor, WA
Maybe you just need new motor mounts. Balance shafts are just creature comfort for the average consumer. If they were absolutely necessary, we wouldn't be deleting them, but they aren't necessary at all.
 

belize1334

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Nov 18, 2003
Messages
3,316
Location
Bozeman, MT
The added stroke makes the harmonics stronger but doesn't change their nature so there's no reason that 4g63 balance shafts wouldn't help. They just might not be as effective as on a 2.0L build. But you should also keep in mind that the lighter pistons and rods will partially offset the effect of the longer stroke. If I end up putting together this 2.3 that I'm (potentially) buying it'll have 4g63 balance shafts in it. That is assuming that they don't interfere with the rods. I've heard rumors of fitment problems between the rear shaft and some of the heftier aftermarket rods.
 
Last edited:

minneSNOWta

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Joined
May 14, 2011
Messages
363
Location
Eagan, MN
When I had my car at Archer, the older mechanic was not feeling the BS delete on my 2.3. Apparently they did not delete their balance shafts for race applications and spoke of no failures IIRC. He told me it could shake bolts loose and I can see where he is coming from. Using the stock harmonic balancer too. With all polyurethane mounts, it really shakes. Maybe keeping the side mounts stock would have been a better idea. You can feel the vibration in the cabin, but to me it isn't bad. The steering wheel vibrates the most and made my friend's hands tingle. He didn't seem to mind at all, judging by his perma-grin. I don't have experience driving it myself yet, so I can't give my opinion yet.
 

G

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Feb 24, 2004
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zompton
Are your engine mounts stock or aftermarket?
 

tsitalon1

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Joined
Dec 29, 2010
Messages
309
Location
Montgomery Al
Quoting raptorreed:
Maybe you just need new motor mounts. Balance shafts are just creature comfort for the average consumer. If they were absolutely necessary, we wouldn't be deleting them, but they aren't necessary at all.



This may be true with the 2.0l, but mitsu did not intend to build the 2.3l. That is a monster we came up with that introduces all kinds of nasty harmonics. - Just google the "To stroke or not" PDF file.
 

tsitalon1

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Dec 29, 2010
Messages
309
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Montgomery Al
Quoting belize1334:
The added stroke makes the harmonics stronger but doesn't change their nature so there's no reason that 4g63 balance shafts wouldn't help. They just might not be as effective as on a 2.0L build. But you should also keep in mind that the lighter pistons and rods will partially offset the effect of the longer stroke. If I end up putting together this 2.3 that I'm (potentially) buying it'll have 4g63 balance shafts in it. That is assuming that they don't interfere with the rods. I've heard rumors of fitment problems between the rear shaft and some of the heftier aftermarket rods.



Hey belize, I was wondering if the longer stroke somehow changes the timing neccessary for balance shafts.

What rods have you *heard* interfere with the 4g63 Balance shafts?
 

tsitalon1

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Joined
Dec 29, 2010
Messages
309
Location
Montgomery Al
Quoting G:
Are your engine mounts stock or aftermarket?



They are currently stock in my GVR4.

They were also stock in my eclipse with the Magnus 2.3l as well. - Bad harmonics here with this one!
 

tsitalon1

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Dec 29, 2010
Messages
309
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Montgomery Al
To be fair, I don't know if Magnus ever balanced that 2.3 or not. I bought the shortblock from them many years ago - Ended up selling that eclipse.
 

prove_it

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Jul 3, 2008
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Sioux Falls, SD
Sounds like your better off just have the whole rotating assembly precision balanced. It will help with vibration, but also will help with bearing life and power.
 

belize1334

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Joined
Nov 18, 2003
Messages
3,316
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Bozeman, MT
The longer stroke doesn't, in principle, change the timing of the harmonics. However, the smaller rod ratio does. If you read the "stroke or not to stroke" white paper he has a bit on harmonics and you can see that it sort of widens and flattens the harmonic profile. But, the balance shafts aren't that sophisticated. They are just a simple counter weight that spins at 2x engine speed. Even on a 2.0 they don't perfectly counter the harmonics, but they get you 90% of the way there. Same on a 2.3L build. The balance shafts won't perfectly cancel everything, but they'll still get you most of the way there.
 

Street Surgeon

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Mar 3, 2004
Messages
941
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Omaha, Nebraska
If you do end up using balance shafts, make sure you use the ones from the 4G64 and ensure that they clear.
 

tsitalon1

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Joined
Dec 29, 2010
Messages
309
Location
Montgomery Al
Quoting Street Surgeon:
If you do end up using balance shafts, make sure you use the ones from the 4G64 and ensure that they clear.



Confused - Why? You seem to be the only one stating the 4g64 BS are required in a 2.3l. Do you have direct experience with this?
 

belize1334

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Nov 18, 2003
Messages
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Bozeman, MT
The 2.4L balance shafts will be a little heavier to accommodate the longer stroke of the 100mm crank shaft. But, as has been said, a built motor also has a lighter rotating assembly. So while the 63 shafts may undercompensate for the secondary harmonics, it's equally possible that the 64 shafts would overcompensate. Which is better? IDK.
 

Street Surgeon

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Mar 3, 2004
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Omaha, Nebraska
My advice comes free of charge, but I'm not tech support /ubbthreads/images/graemlins/wink.gif Use whatever you like, I would recommend the 4G64 shafts if you absolutely have to have them and they may need machining. I do have direct experience with this, and a much wiser man then I made that recommendation.
 
Last edited:

tsitalon1

Well-known member
Joined
Dec 29, 2010
Messages
309
Location
Montgomery Al
Quoting street surgeon:
My advice comes free of charge, but I'm not tech support Use whatever you like, I would recommend the 4G64 shafts if you absolutely have to have them and they may need machining. I do have direct experience with this, and a much wiser man then I made that recommendation.



Thank you for your help - I will look into this!
 
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