Balance shaft removal - WTF

[Turbo047]

I've heard a lot of talk about removing the balance shafts from the Astron engines.

I listened to the talk and bought a kit to remove mine.

But OMG it was the worst thing I ever did.

Between 3000 and 4500 rpm the car had a terrible vibration. I have a Sigma Turbo I like to have it in that rev range. It was horrid so I put the balance shafts back in.

My question is do you guys really recommend removing the balance shafts? What do you gain?

[GB_BB4C]

usally we remove them when rebuilding the motor, so you get the motor balanced at the same time. this will remove the unwanted vibration that you are getting. they are there for a reason, to balance the motor.

[geezer101]

The balance shaft compensates for the bottom ends dubious factory balancing and machining. Although it does a good job on keeping the harmonics on a stock engine in check, it robs the engine of power and is a weak point when you start demanding more out of it. If you are going to go for a performance tuned engine it will need the crank lightened and balanced along with the rods being weight matched. Good quality performance engine builds are $$$ but unless you end up destroying the bottom end from abuse or neglect, it's a one off investment that is worth it. A balanced bottom end on the turbo engine with have all sorts of positive effects - faster spool up, smoother revs and better all round response.

[Turbo047]

Man I've been abusing my bottom end for 20 years. It is stock and I hate to say but I had a pretty "give a shit" attitude to the engine. My last wife would start all kinds of hell if I wanted to spend any money on my car for parts that didn't break. So I tried to wreck diffs, gearboxes and the engine. If something broke I was allowed to fix it. But to my surprise I COULD NEVER BREAK ANYTHING!.BUT I DID TRY. So Ive been running the same mechanical's since 1992.

One thing though, I did sell the car to my brother in law for about six months and he did root the waste gate diaphragm, over boosted it and broke a compression ring in No 2 Cylinder. But on the good side, he "had a mate" that was a "mechanic" and said it's only a Sigma so it wasn't worth fixing! So I got it back at no cost.

Anyway back to balance shafts. I'm keeping mine in. It runs smooth as. People have actually said how smooth she runs.

[leoca64]

...theres more info on this topic on the old site.

[bruggz351]

Sooo, should I leave the balance shafts where they are for the time being?
I'm just changing the timing cover and thought I may as well rid meself of teh rattle in the front by deleting the balance shafts...

cheers

[Turbo047]

If you have a rattle from the front you can adjust the tension (or remove the slack) from your balance shaft chain through the little 2 bolt cover on the timing cover. Maybe worth a try.

[BAD-SIG]

I've removed the balance shafts on all the stock engines I've had over the years and never regretted it. Yes I notice a little vibration between 3500-4000 revs (specially if looking in the interior rear view mirror, you can see it vibrate a little) but who cares, it's free horsepower! The engine feels a lot more elastic and revs much quicker. If you ever have the chance, pick up and hold the two balance shafts in your hands and imagine how much power it takes for the engine to spin these stupid paperweights! Yes they smooth the engine vibrations, but I guess maybe I've been lucky with my stock engines over the years because I never noticed much vibration without the balance shafts. I still think it's definately a cheap and worthy upgrade and will be doing it to yet another of my Sigmas in the coming months (I already bought the kit). The other plus too is it saves your car at least 10kgs!!

I did weight the balance shafts once years ago but can't remember how much they weighed, can any one try and let us know how heavy they are please? I know they are much heavier than a camshaft and there's two of the balance shafts!

[cheaterparts]

I've heard a lot of talk about removing the balance shafts from the Astron engines.

I listened to the talk and bought a kit to remove mine.

But OMG it was the worst thing I ever did.

Between 3000 and 4500 rpm the car had a terrible vibration. I have a Sigma Turbo I like to have it in that rev range. It was horrid so I put the balance shafts back in.

My question is do you guys really recommend removing the balance shafts? What do you gain?

on slower reving engines it doesn't make a lot of difference to reliability so bang them back in - higher reving engines the balance shafts become a liability and the reason is simple enough.
you have 2 shafts that are made out of balance on purpose running at double the speed of your engine , the forces of that out of balance gets worse and the speed increases
myself I couldn't think of any thing worse than fitting them back in my own engine of cause that runs most of its time high in the rev range
with normal gear changes just over 7000 .
these speeds do chop out the balance shaft bearings fairly quickly , of cause there is also a performance gain by not having the engine driving them.
like I said I dont use them and dont seam to have any Vibs that I notice it may go through the harmonic faze quick enough that its not noticed

The balance shaft compensates for the bottom ends dubious factory balancing and machining. Although it does a good job on keeping the harmonics on a stock engine in check, it robs the engine of power and is a weak point when you start demanding more out of it. If you are going to go for a performance tuned engine it will need the crank lightened and balanced along with the rods being weight matched.

all inline 4 cylinder engines produce this harmonic balanced or not as its impossable to make the balance factore perfect.
the larger/heavier components in the astron are always going to produce a larger harmonic than a smaller/lighter engine

Man I've been abusing my bottom end for 20 years. It is stock and I hate to say but I had a pretty "give a shit" attitude to the engine. My last wife would start all kinds of hell if I wanted to spend any money on my car for parts that didn't break. So I tried to wreck diffs, gearboxes and the engine. If something broke I was allowed to fix it. But to my surprise I COULD NEVER BREAK ANYTHING!.BUT I DID TRY. So Ive been running the same mechanical's since 1992.

the good old Mitsubishis are pretty tough but I had found std diffs break easy enough even with a NA 2.6 so did scorp diffs and I even broke a H190 datson diff ( almost impossable to break ) it also sheared off the gearbox output shaft at the same time that was going fron 2nd to 3rd gear at morwell hillclimb

[bruggz351]

Thats awesome info gents.
I've left the shafts in this time round, but still have the eliminator kit so anytime in the future if I feel the need its all there.

I will give the adjustment a go to see if that quietens things.

cheers

[MRGNLC]

whereabouts do you get these "eliminator" kits?

[bruggz351]

^^ Got mine off eBay....

cheers

[MRGNLC]

thanks
just got one for my rebuild

[RaptorReed]

Mitsubishi balance shafts have always just been a creature comfort thing...look at the original 4G52, no balance shafts. When balance shafts break in a g63, epic chain reaction of carnage to the motor usually follows.

The kits are only 15-$30.