Balance shaft?

[savage1987]

Found a couple of opinions on whether or not to run a balance shaft in a street engine.. looking for more.

Generally you only remove the balance shaft to be able to run a double row timing chain. I dare say that speedway engines would be running double row timing chains for durability, hence the balance shaft removal. On a street engine, there isnt really a lot of point as even if you are running a nice cam, an aftermarket single row chain will be more than capable.

You will probably be picking up bits of v6 at some stage down the track as the v6 is naturally very harsh and kills engine mounts WITH THE BALANCE SHAFT IN! Take the balance shaft out without spending $$$ on balancing the bottome end - the poor vn will fall apart in no time.

My 5 cents worth.

I should add I'm asking with respect to my VR V6 stock rebuild to go into the VN

Let me know your thoughts!!
Sam

[Zuicider]

heard your crank can shatter also

[centy]

Hell i was told the harmonic vibrations would crack the block.
However i DO NOT know that this is true.
Best to find someone who has done it.

[Pub247]

Ive done it on a Balanced bottom endi wouldnt take it out otherwise

[savage1987]

Balanced bottom end has nothing to do with it from what I've been reading.. the 90degree V6 can never be properly balanced as a system.. The balance shaft is apparently there to reduce the 3rd harmonic vibration or some such.. just a NVH thing from the factory as a niceity.

HOWEVER because I don't want my VR V6 to run/sound like my old rattly VN s1 V6, please put that shaft back in Paul

[immortality]

i'm running a VN s1 without a ballance shaft, engine is stock otherwise. with decent engine/trans mount do don't notice it much. no shattered crank or block yet the double row chain removes the use of a chain tensioner, thats a bonus in my book. from what i understand the ballance shaft is there to make the owner/driver happy because a smooth engine is better (in the mind) then a slightly unballanced one. i have read that a unballanced engine does not effect the final perfomrance of a engine in terms of power. for me, the double row chain also worked out cheaper then the single row version

[Pub247]

my mate's balanced v6 without shaft is no different to any other vn vp v6 ive been in, you couldnt even tell it was missing the shaft.
Anyways we went with the single heavy with stage 3 crow cam kit mainly cost was factor as through my work crow stuff is cheap tensioner was $10. If you were paying retail then i could understand double timing chain could be cheaper.

[savage1987]

hmm... maybe I shall leave it out.. got a plug the right size for it Paul?

[Pub247]

theres nothing to plug on vn-vr only ecotecs have a gallery on the rear bearing housing

[savage1987]

ok. I read you needed a plug to stop oil actually leaving the motor.. but then again I read a lot of bullshit on this topic last night. Motors breaking mounts, idling like shit, etc.. still deciding what to do about this shaft lol

[leigh 7005]

needs to be balanced if you remove the balance shaft

[savage1987]

fail.

From what I've read last night that is commonly said, but completely wrong. A 90degree V6 is naturally off balance regardless of how well balanced the parts themselves are.

It's not there to balance the bottom end.. it's there to counter harmonic vibrations (the engine's 3rd harmonic or some such). If it were there to replace bottom end balancing, each motor would have to have a differently weighted shaft installed. Doubt very much that Holden went to that much effort lol

[Thomas1]

Pffft. Mine isn't hooked up anymore (it's still sitting in there cause I didn't want to have to plug the rear hole, but the gear isn't connected). I haven't noticed any more vibrations at all. But I do have a fairly large cam in there . My engine hasn't been balanced either...it's still a stock bottom end.

Ditch it

I find that the removing balance shaft topic is like a mini spool topic. Those who have never done it/had one tell you it's bad, and those who have tell you to remove it/they are good....

[leigh 7005]

ok i just thought it was like the astron engine ones you remove them you gain hp and losse weaight

[ScoHar]

Yea with the Mitsi's you don't have to balance them when removing the balance shaft as engine rotating mass balance is different to what a balance shaft is trying to equalize, balance shafts are really there for driver comfort/smoother engine. I sell Mitsi Balance shaft removal kits i.e frost plug 2 threaded plugs and another size frost plug, and most people I have sold them to have just pulled it out plugged it up. I know its not much use cause were talking about Holden 3800, but they do the same job.

*EDITIf you do balance them without the balance shaft it'll be a bitch to get the right balance ratio but can be done, not by the factory specifications as they will be wrong without the shaft.

and....apparently you gain HP in the 3800 because there is less drag on the timing/drive train sides of things, not sure about mitsi's on that one as most run a separate balance shaft belt.

So in short go for it if you want.

[immortality]

holden did alter the weights ofthe ballance shafts between models. the fact that the buick has a rough idle is inpart because the factory ballance is crap. you can achieve a much better ballance and smoother running engine with a proper ballance job, this doesn't alter the fact as has already been stated that with a 90degree V6 things are never going to be as smooth as a inline 6. but don't ever live under the illusion that the factory ballance can't be improved upon.

with regards to removing the ballance shaft on the buick, there is nothing that needs "pluggin up" when it is removed. there is a frost plug behind the rear needle bearing, however you would only remove this if you were changing the needle bearing(if you were intending to keep the ballance shaft). seeing as your just removing the ballance shaft, you can leave the bearing in place and it will be fine.

[PaRaDoX]

as my engine builder said to me,

you cant properly balance a v6....

only inline4, inline6, v8 (and i doubt anyone knows someone who has pulled down a v12)

factory balance is within 10 grams, a proper balance should be within 1-2grams

[savage1987]

OK where I stand now is exactly caught between taking it out and leaving it in. I don't think it's a big deal one way or another.

This motor (VR V6 rebuild) is going to cop about 8psi from a turbo soon enough.. does that make my decision any easier?

[Pub247]

paradox you can balance a v6 properly as long as theyre a 60 degree one not 90

[delcowizzid]

you can 100% balance the 90 degree v6 as well but they try to lift up off the engine mounts when they are done like that hence why they are not done like this from factory and have the balance shaft to tidy up the resulting vibrations to make the engine smoother.some people get vibration removing the balance shaft some dont each engine is different. vn and vp allso have different weight shafts to suit the different weight cranks as well just on a side note.and yes as said above you can balance the 60 degree v6 as above and they have no balance shaft due to the fact they are 60 degree and are balanced 100%

[savage1987]

Yeah, 60degree V6s are the ones you can get right.. makes me wonder why 90degree ones exist.

Turbo make any diference to whether or not to retain the shaft?

[ScoHar]

if your having your engine rebuilt, shouldn't you ask your rebuilder what he reckons you should do, considering at the end of the day he's doing the work that well should be guaranteed so he will know whether it'll fall apart or not.

[savage1987]

Nope, my good friend paul (zuicider) is rebuilding it. He has run motors both ways with no problems.

heard your crank can shatter also

lol, he gives me such faith

Where I'm at now is trying to decide which option will provide the better end result with boost. I think it'll end up being left in the motor as per factory.

[savage1987]

just for the record, I ended up using the balance shaft.

like jason (greenfoam) said to me, how important is 3hp??