Different balance shaft option

[mndsm1g]

Saw this recently and was wondering what people thought of it as an alternative to the typical stub shaft people use in the kits everywhere.

http://www.qprinc.com/qprmain.html

 

[krisj144]

I've heard about using the stub as being harmful to your oil pump and it makes sense. Then again, I've been running without balance shafts for about 2 years now with zero problems.

on a side note....sweet jesus, what high prices they charge! 500 to assemble a shortblock and 250 to machine 1g rods to fit 2g pistons?!

 

[dsmayhem]

Yes its an option...but part of why I will be removing my balance shafts is to eliminate the chance of the balance belt talking out my timing belt. :thumbdown Plus balance shaft bearing failures suck.

But on the good side its good to see people are comming up with new ideas!

 

[seeker]

It says very clearly that this is the rear shaft, not the front that the belt is on. It is actually just used rather than a stub shaft. The front shaft would be gone as well as the belt.

 

[dsmayhem]

My bad. Wouln't be a bad deal if it wasn't 2X as much as a BS elim kit.

 

[MustGoFaster020]

I am running one of them. I think it is a very good idea. With the stubby shaft there is only one bearing surface to hold the gear. Too much potential for it to start grinding into the case for my tastes. With the balance shaft (cut down or stock) you have two bearing surfaces so it doesn't have a chance to twist and grind the case. With the cut down one there is really not much of a chance for the bearing to fail since there is no large weight spinning around and making who knows how much outward force. I see many ups and no downs (besides $) to this. I spent the little extra for it, for insurance purposes, no need to be building another motor sooner than I should have too.

 

[98TsiAWD]

I've heard about using the stub as being harmful to your oil pump and it makes sense. Then again, I've been running without balance shafts for about 2 years now with zero problems.

on a side note....sweet jesus, what high prices they charge! 500 to assemble a shortblock and 250 to machine 1g rods to fit 2g pistons?!

bah, many DSM shops charge $350-400 to machine 1g rods. $500 for a full assembly isnt really that bad when you look at labor rates.

 

[MNRaptor]

As the one building the engines, I can tell you $500 is actually a pretty good deal for what goes in to them. This isn't your typical built in the garage engine.

 

[LEKS]

Why waist the time of putting something back in when its allready out, and pay money for a turned shaft. Pay the 40 bucks for the kit and do it all at once. :thumbdown wate of time and money

 

[MNRaptor]

Do some checking on the various boards and you will see there has been many problems from running the typical stub shaft for elimination. Not everyone experiences it, but it has been found many times that the front case will end up worn out which can result in many problems including oiling issues since that is where your pump gears are. People that thought they were going to do it just once as you say, found out differently resulting in major engine damage. That is what this shaft was designed to prevent. So in reality, if you really want to only do it once, this should be a better option.

 

[loreak]

ive been on dsm forums regularly for 5 years, never heard once of any problems with the stub shafts

 

[pneumo]

ive been on dsm forums regularly for 5 years, never heard once of any problems with the stub shafts

Same here.

I don't know if you guys have taken an oil pump apart, but there is no load on the stub shaft. It's just a shaft bolted to a gear that spins in oil. That's it. The stub shaft doesn't have to handle any torque, it's just there to keep the gear centered in the oil pump housing. Just make sure you have a good oil pump housing, not one that is all chewed up from the balance shaft oscillating inside it, and you'll be fine.

 

[kpt4321]

The theory is that the timing belt will cause a load on the shaft that can cause undue wear.

That said, I am running the standard stubby shaft in my car.

If I was going to build a race motor, I would use a machined-down OEM rear shaft.

 

[pneumo]

The theory is that the timing belt will cause a load on the shaft that can cause undue wear.

Yeah, see, that's not the right reason. The oil pump has two gears. The first gear (drive gear) is attached to the oil pump sprocket which is turned by the timing belt, and the other gear (driven gear) is attached to the balance shaft. Removing the balance shaft doesn't affect the load bearing ability of the drive gear. Plus the oil pump sprocket already has more support than the balance shaft/ stub shaft.

 

[BUCK]

Taboo is the MAN on this - I wish he posted here more...

 

[MNRaptor]

There are quite a few threads covering this type of shaft mod, you can check on this board as well as several others by searching for "balance shaft lathe", It should bring up quite a few responses.