Rebuilding, should i remove the balance shaft?

[jrpmp69]

I am rebuilding the bottom end of my 98 Eclipse GST with forged pistons and rods, should the balance shafts be removed before it is put back together? What are the benefits of removing the balance shaft?

 

[STECARS]

YES, AND I'M NOT EXACTLY SURE.

 

[4g63tsiawd]

yes remove your bs it takes mass off of your engine and will let it rev alot easier the down side is it will make your car vibrate more

 

[jrpmp69]

What are the cons of not removing the balance shaft?

 

[STECARS]

Well im not sure there are cons , Pros are one less thing to go bad or wrong and as stated above. Also i havent heard of many people doing a rebuild and not performing this mod. It saves some weight and frees up a little power. One lees belt you got to buy or worry about snapping.

 

[STECARS]

You can live with the vibration , its nothing extreme.

 

[riceburner]

all they do is quiet outside noise from your motor if you remove them you will have better oil pressure and be able to hold more oil i think around a quart more

 

[jrpmp69]

can i just remove the rear balancer and install a stub without having to do the other complicated stuff with the front one? Where can i find these instructions?

 

[STECARS]

http://vfaq.com/mods/balance-shafts.html

 

[Boosted98gsx]

Yes, you can remove the rear shaft, and replace it witha stubb and leave the front one in and just dont install the front's belt. That is what i did. It will still block off the oil passage in bearing.

 

[jrpmp69]

That VFAQ is for a 1g bs removal, are the part numbers still the same? Will the stub in the VFAQ fit a 2g engine?

 

[jrpmp69]

I also had my assembly balanced at the machine shop, will removing the balance shaft affect the balance of the assembly at all?

 

[slowAWDTSi]

Originally posted by riceburner
all they do is quiet outside noise from your motor if you remove them you will have better oil pressure and be able to hold more oil i think around a quart more

Easy killer no oil room is freed up by the balance shafts. They dont float in oil. It takes the same oil on all cars unless you change the pan.
Dru

 

[Dream On]

Another thing i've heard is that if it snaps, it can take out your timing belt.

 

[Boosted98gsx]

Originally posted by Dream On
Another thing i've heard is that if it snaps, it can take out your timing belt.

Haveyou ever seen a balance shaft? I dont think it's possible for one of them to snap from just spinning. But no, if one of the snaps the worst that could happen is lower oil pressure and a vibrating engine.

Originally posted by jrpmp69
That VFAQ is for a 1g bs removal, are the part numbers still the same? Will the stub in the VFAQ fit a 2g engine?

Yes the part numbers are the same. It's the same engine.

Originally posted by jrpmp69
I also had my assembly balanced at the machine shop, will removing the balance shaft affect the balance of the assembly at all?

The assembly balancing that they do and the machine shop is for the crank and pistons. They should have removed the shafts themselves. And it's weird that they didnt. All the machine shops that i know that balance the rotating assemblies always take out the BS as they are pretty much useless.

 

[slowAWDTSi]

Originally posted by Boosted98gsx
Haveyou ever seen a balance shaft? I dont think it's possible for one of them to snap from just spinning. But no, if one of the snaps the worst that could happen is lower oil pressure and a vibrating engine.

Well I think he was talking about the balance shaft belt snapping. If that goes it usually gets caught into the timing belt and throws it off Then you are in a whole new world of sh!t
Dru

 

[1LE]

Originally posted by slowAWDTSi
Well I think he was talking about the balance shaft belt snapping. If that goes it usually gets caught into the timing belt and throws it off Then you are in a whole new world of sh!t
Dru

I've seen that happen to the same person multiple times. Not a pretty sight. My opinion is to get rid of the balance shafts ASAP!

 

[jrpmp69]

Originally posted by Boosted98gsx
The assembly balancing that they do and the machine shop is for the crank and pistons. They should have removed the shafts themselves. And it's weird that they didnt. All the machine shops that i know that balance the rotating assemblies always take out the BS as they are pretty much useless.

I only took the engine block, new forged pistons for boreing, new rods and crank so they could balance the assembly, my mechanic is putting the engine back together.

Thanks for the help on the part numbers, i was thinking about only putting a stub in and leaving the front balance shaft with no belt, but since i'm putting in a new oil pump i think it would be better to just do the rest of it.

 

[Dream On]

Originally posted by slowAWDTSi
Well I think he was talking about the balance shaft belt snapping. If that goes it usually gets caught into the timing belt and throws it off Then you are in a whole new world of sh!t
Dru

Thats what I meant. Nice save.

 

[4pistons]

What are the cons of not removing the balance shaft?

I've had my '91 GSX for about 100K miles and I just broke my 3rd balance shaft belt!
The first time it took out my timing belt, bent all my valves and cost me $1000 to fix. These last two times I was luckier and it just wedged itself behind the crank sprocket. But that's it! No more belt trouble for me, they're coming out!

Rick - '91 GSX

 

[Damn 2nd Gear]

hmm can i just reach back there and take the belt off? (well not exactly reach..) id like to just remove the belt when i do my timing belt this summer.

 

[jrpmp69]

I have removed both balance shafts on my car, the 2g eclipse is slightly different than the 1g shown in the vfaq. The rear balance shaft has a cover on the oil pump that screws off to get to the bolt that holds the balance shaft, theres no need to remove the oil pump to remove the balance shaft.
With both balance shafts removed and the forged pistons and rods, i eliminated tons of weight from the rotating assembly.
If all goes well, i plan on intalling a HRC 20g turbo on my eclipse.

 

[jrpmp69]

Originally posted by Damn 2nd Gear
hmm can i just reach back there and take the belt off? (well not exactly reach..) id like to just remove the belt when i do my timing belt this summer.

If you only remove the belt, the rear balance shaft will continue to turn with the oil pump, you will only stop the front balance shaft from turning, plus you will still have the extra weight.

 

[jrpmp69]

Originally posted by 4pistons
I've had my '91 GSX for about 100K miles and I just broke my 3rd balance shaft belt!
The first time it took out my timing belt, bent all my valves and cost me $1000 to fix. These last two times I was luckier and it just wedged itself behind the crank sprocket. But that's it! No more belt trouble for me, they're coming out!

Rick - '91 GSX

If you had to take apart your engine to fix these problems, why didnt you just remove the balance shafts the first time this happened to you?

 

[Damn 2nd Gear]

but the risk of it snapping is gone and its alot easier for us learning to DIY on all our engine work. this summer ill be learning to do t-belt, camshafts and water pump. i think i should do oil pump but i dont know if i have to have the tbelt off to do it. if i do then i will do it all at the same time. the BS removal looks a bit intimidating, ill wait untill im more comfortable with the whole lifting the engine thing. then ill get that with the motor mount mod too.