2.3 Stroker...Balance shaft question!!!!!

[herostar]

I took mine out, no problems here. The engine was balanced and blueprinted, so it idle's smooth as silk

 

[Defiant]

Wow.

The Silent Shafts' job has nothing to to with "engine balance". They're there only to combat a physical shortcoming in the circumstance of the design of the inline 4-Cylinder engine, where the big ends try to move the lower end of the block left-to-right (or, back-and-forth in the transverse DSM engine). All the duty of the Silent Shafts is to cancel this. Having an engine "balanced" won't have an effect on this secondary imbalance, and neither will a hamonic "balancer", or damper. The damper's job is to absorb crank windup as the twisting forces are fed into the crank, and feed it back in with a great reduction in twisting stress loads on the crank. The harmonic "balancer" does nothing to "balance" the bottom end. "Balancing" an engine means to assure that all the rod/pin/piston assemblies weigh the same, and that the mass of the crankshaft is evenly distributed around its centerline. This won't do anything for the secondary imbalance of a 4.
The disadvantages of the Silent Shafts are that they take (minimal) power to turn, add to the stress of the cam belt in the case of the rear shaft, add the belt failure possibility in the case of the front shaft, and most importantly, have plain journal bearings which are subject to failure because they turn at twice crankshaft speed, and while making the engine feel inline-six smooth, mask from the driver the amount of violence they're enduring. Journal bearings don't like 14,000 rpm runs, and the less so when the rear bearing is oiled from the inside of the shaft itself instead of from an adjacent gallery.

 

[Forces32psi]

so running the 2.3 w/ no balance shafts and a aftermarket underdrive pulley (unorthadox) is probably a bad idea?? running the 2.3 w/ no balance shafts and the stock 2.0 dampener should be fine though?? i never really thoght about that.. the ONLY reason i got the underdrive pulley was so i could turn 8500-9000 rpms w/ my 2.0 but since im not trying to turn that high rpm then i shouldnt need the under drive pulley then correct??

 

[peregrine]

so running the 2.3 w/ no balance shafts and a aftermarket underdrive pulley (unorthadox) is probably a bad idea????

no. have your machinist balance your crank with the under drive oulley and youll be fine.

running the 2.3 w/ no balance shafts and the stock 2.0 dampener should be fine though?? i never really thoght about that.. the ONLY reason i got the underdrive pulley was so i could turn 8500-9000 rpms w/ my 2.0 but since im not trying to turn that high rpm then i shouldnt need the under drive pulley then correct??

yes, that is correct. you shouldnt have to go over 7500 rpm with the stroker anyways.

 

[Forces32psi]

no. have your machinist balance your crank with the under drive oulley and youll be fine. yes, that is correct. you shouldnt have to go over 7500 rpm with the stroker anyways.

ya that kinda sucks.. im suppose to go pick my shortblock up tomarrow ........all put together allready w/ the 2.3 crank.. i dont really care if i run the underdrive pulley or not i guess.. the car doesnt get driven that much and i only have the underdrive pulley for the crank and not everything else.. so i guess il just run the GOOD stock 2.0 pulley i have.. but will that pulley be ok w/ the 2.4 crank?? steven

 

[peregrine]

yes it will be fine.

 

[loweperf]

Wow.

The Silent Shafts' job has nothing to to with "engine balance". They're there only to combat a physical shortcoming in the circumstance of the design of the inline 4-Cylinder engine, where the big ends try to move the lower end of the block left-to-right (or, back-and-forth in the transverse DSM engine). All the duty of the Silent Shafts is to cancel this. Having an engine "balanced" won't have an effect on this secondary imbalance, and neither will a hamonic "balancer", or damper. The damper's job is to absorb crank windup as the twisting forces are fed into the crank, and feed it back in with a great reduction in twisting stress loads on the crank. The harmonic "balancer" does nothing to "balance" the bottom end. "Balancing" an engine means to assure that all the rod/pin/piston assemblies weigh the same, and that the mass of the crankshaft is evenly distributed around its centerline. This won't do anything for the secondary imbalance of a 4.
The disadvantages of the Silent Shafts are that they take (minimal) power to turn, add to the stress of the cam belt in the case of the rear shaft, add the belt failure possibility in the case of the front shaft, and most importantly, have plain journal bearings which are subject to failure because they turn at twice crankshaft speed, and while making the engine feel inline-six smooth, mask from the driver the amount of violence they're enduring. Journal bearings don't like 14,000 rpm runs, and the less so when the rear bearing is oiled from the inside of the shaft itself instead of from an adjacent gallery.

Amazing that your the only one that knows about harmonic vibrations in this whole thread! Just a couple things to add.First underdrive pulleys are usually just that Pulleys. Usually they have no harmonic dampening capabilities. Second anybody that thinks the balance shaft help with crank vibration need to think about them being connected to the crank by a belt don't you think the belt might impede any dampening the B.S. would provide?

 

[Defiant]

Please read and consider:
http://www.dsmtuners.com/forums/showthread.php?t=181105

The harmonic damper may matter quite a lot.

 

[loweperf]

I don't know if your last post was directed at me or not, but what I was trying to point out was I would never run an engine without some type of dampner. Most underdrive pulleys don't provide dampening and I would rather risk a stock one coming apart than run without one.

 

[boostyGST]

well after reading all of this, I am still confused on the issue, someone needs to take the initative and find some hardline facts about the vibration comparison. I have a good old 2.0 4G63 and i just bought the removal kit from SBR, from what i have read on here, it is 100% ok to do this to the 2.0 right?

 

[boostedinaz]

well after reading all of this, I am still confused on the issue, someone needs to take the initative and find some hardline facts about the vibration comparison. I have a good old 2.0 4G63 and i just bought the removal kit from SBR, from what i have read on here, it is 100% ok to do this to the 2.0 right?

Its a 100% OK with any displacement. Like I said before it would be impossible to do any type of test.

 

[Forces32psi]

i dont care to take any chances.. i have a 2.3 stroker, w/a fp3575 and i dont care to ruin anything.. its expensive!!! i pulled of the underdrive pulley and will be putting the stocker back on. my block doesnt have the balance shafts and they dont have anything to do w/ the harmonics anyways..im not to worried about the little tiny bit of hp il lose and the tiny bit of reving quicker i would gain. im SURE that everything else im running will MORE then make up for it. and it will last as well.

 

[turbohounds]

Please read and consider:
http://www.dsmtuners.com/forums/showthread.php?t=181105

The harmonic damper may matter quite a lot.

Defiant,

Please remove my bearing picture, or separate it from the broken cranks. It was my example of 100k mile bearings after 50K+ miles of using an undampened pulley on a 13.2s car regularly autocrossed. It only provides misinformation to group this with broken cranks.

Perhaps it paints a different story if you match the bearing to the picture, and mention this case, although an n of one, showed only minor bearing wear, possibly attributable to grit in the oil. No damage was found to the crank.

Although, if someone would like to find a way to blame the invisible crack through the water jacket at the bottom of every piston wall on the pulley, I wouldn't mind hearing that.

 

[akdsmer]

Quick question guys! I just finished my 2.3 stroker build and was wondering if I should be doing the balance shaft elimination. A local builder/shop around said they'd highly recommended putting the balance shaft on. I did a search on this and a couple of guys mentioned that the 2.4 crank will be hitting the balance shaft (in some cases)....is this correct? I would rather get rid of the balance shaft.....and be done with it. What's best for the 2.3 stroker block.....what do you guys think? Thanks in advance!

I didn't see anyone else address this. On my 2.3 build (94 7bolt) My balance shaft hit my eagle rods on cylinders 2 and 3. I had to clearance the balance shaft to clear this (.25 inches). I also did the same to the other shaft to keep the weights the same. A very big pain in the ass to keep them symmetrical. I will be starting mine up here in the next day or two. If there is any vibration issues, I will remove the balance shafts. MY decision was to leave them in there.

 

[Erik95GSX]

I don't know but you all have a good debate going on here but if you realy want to know like he said call a shop like slowboy or busher racing. they all build motors and have fast car and want as much pony for there buck if you realy want to know. instead or wasting your time talking about it. but i had a realy laugh thanks

 

[KJS1820]

I took mine out with my stroker and use the stock crank pulley! My car runs very smooooth hard to tell they are out! my exhaust and crower stage 3s make the car shake more than the shafts coming out i am sure you have all seen this but here is a great link anyway http://www.vfaq.com/mods/balance-shafts.html