[ash]

Here's another write-up:
http://www.b15u.com/sentra-specific-installation-guides-technical-info/16792-qr25de-free-balance-shaft-removal.html

Here's the JWT write-up for their kit:
http://www.b15u.com/sentra-specific-installation-guides-technical-info/9143-jwt-balance-shaft-removal-bsr-kit-installation-instructions.html

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A little history on the Balance Shaft - Written by MotoIQ.com

The balance shaft assembly is found in the bottom of the oil pan submerged in oil. It is the weakest link in the chain when the QR25DE is modified. For 2007+ Sentras, the JWT balance shaft removal kit will not work, the chain powering the balancer can be cut.

One of the first issues that JWT addressed in our motor is the problems of seizing balance shafts. Balance shafts work to cancel out a 4 cylinder engines inherent up and down shaking moments and spin at twice the crank rpm. This means that at 6100 rpm the shafts are zinging at 12200 rpm, it’s a small wonder that they have problems with seizing in their housings. If you raise the rev limit much past the embarrassingly low stock limit of 6100 rpm, the balance shafts seize in their bores creating a chain of events that destroys the engine. On the QR, the balance shafts are the first failure point.
JWT also felt that the balance shafts helped to contribute to some of the QR25's other problems, excess oil consumption and bearing failure. The balance shafts are submerged in the oil pan and when spinning at 12,000+ rpm they churn the oil to a frothy mixture of oil and air. This aerated oil, if ingested by the oil pump can cause bearing failures. The churning balance shafts can also fling oil around inside the block contributing to excess windage and increased oil consumption.

Written By: Obsidian

Tools

Hammer
10mm socket
12mm socket
3 flathead screwdrives of various lengths
6" 3/8 drive extension
3/8" drive ratchet
Large wire brush
Small wire brush
1 bottle of superfast drying OMG expensive ($20 for a can.. seriously) RTV for imports
14" bolt cutters
Scraper
14mm wrench
10mm wrench

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This is what you start with. Luckily for me I had access to an automotive lift.
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First comes first. Drain your oil. This is the 14mm wrench's only job.
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Now to remove those oilpan bolts. 10mm socket. I have a wrench here to see what size it is. Always wear your proper protective equipment. I only where the gloves so I don't get oil all over the inside of my car when I leave.... almost a waste of time. You'll see why later.
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All bolts removed.
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Now the fun part. You got to pry the oil pan off. I had to bang a smaller flathead screwdriver through the RTV. I did it at the front and back of the pan. Be very careful not to damage the pan of the gasket surface on the block.



Here she is removed.
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You have to remove this cover on the passenger side of the engine. It's a pain in the butt, especially when the motor is still warm. There are two 10mm bolts as well as two plastic tabs on the back part of it. Once the screws are removed, you're going to have to bang a small screwdriver between the cover and the B/S assembly, right above the front 10mm bolt. PITA. That took me about 10 minutes to figure out. I had to actually take the bolt cutters to the front bolt because it wouldn't allow itself to come out fully. If you're going to put this on then you need a smaller bolt to replace it with. Also, you will have to remove the oil pickup tube. You will need to remove the 10mm bolt on the bottom of the B/S assembly and the 14mm bolt on the upper portion of the tube.

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After that has been removed you have to remove the pulley that the B/S chain is on. To do that you need a 10mm wrench. What I did was jam a farely large screwdriver between the back part of the chain and the B/S assembly. Then I kept prying it towards the passenger side while I turned the 10mm bolt on the pulley. This allowed me to loosen the bolt because otherwise it will spin and spin the entire assembly.



This is what you're left with. Now for the fun part. Take them bolt cutters to it until it looks like.....

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this. I tried to pry the peices aparts so I didn't cut it but it wouldn't work for me. Also, when cutting the chain be sure to not look at it. I had a few peices fly at me when it broke. To get the chain out of the motor I pulled like hell. It didn't work so I got the front part of the chain down as far as I could by hand. Then I had a friend bump the starter of the car. He bumped it twice and it fell out to what you see there. This chain is actually pretty damn small.

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Replace the oil pick up tube.



Be sure to clean up the gasket surface of the pan very well. Oil leaks happen because people rush.

Also make sure that the mounting surface is very clean. If it doesn't look like this, then you need to keep at it.

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Ready for remounting.



Mounted and ready for oil.

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Don't forget to change your oil filter.

Refill with oil when you're ready.



The large oil mess all over the floor.

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The large oil mess all over me. I got this shit on my face and lips.

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Spare parts.

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[Specvay]

Nice!

 

[mamut]

took me two friggin days to do this...that damn balance shaft didnt want to come out.

 

[Blackout_03SpecV]

Whats the purpose of this operation ?

 

[b15sentraspec]

reduce rotating mass and free up like 5 or 6 whp and all for free!

 

[Casper04]

Wrd....

so let me ask u...i see that u have a set up on da car......do u really feel the difference when u took it out.....cause i kinda wanna do... but the other day when i was at work this spec came in with the b/s removed and the motor was all fucked up....shit was shaking and going crazy.....it would take me like 20 min to take it out.....but let me knw what u think of it

 

[Vamp2RLR]

is this just something to do rather than do the BSR kit?

 

[tweb14]

it is the bsr kit. without puttin all that crap back in

 

[Vamp2RLR]

wouldnt it be beneficial to take the whole assembly out tho?

 

[b15sentraspec]

it is the bsr kit. without puttin all that crap back in

all that extra crap jgy bsr kit has is good it helps pick up the oil. and adds an extra quart of oil.

 

[ash]

The BSR (balance shaft removal) kit allows you to remove the entire balance shaft assembly.

is this just something to do rather than do the BSR kit?

 

[ash]

More info added to the first post...

 

[Vamp2RLR]

ok i already have the JWT BSR so im just waiting til spring time to do it especially cz im caught in this hellasious snow store and cant go get new oil and filter!

 

[mike1121]

The balance shaft assembly is found in the bottom of the oil pan submerged in oil. It is the weakest link in the chain when the QR25DE is modified. One 2006 and later QR25DE's, the balance shafts were deleted.

So, the 2006 Spec V's don't need the Balance Shaft Removed/Chain Cut? Nissan has done it already?

 

[ash]

07+ spec v's don't have balance shafts

 

[mike1121]

Oh ok, Well I'm getting this done when it gets warmer then! How are the vibrations in the car?

 

[b15sentraspec]

so my 06 spec b15 there deleted already????

 

[ash]

no that was a typo...it has been fixed. it's 2007+ Spec V's only

 

[b15sentraspec]

k kool i was gonna say..

 

[SHIFT_Sniper]

Nice write up, Im actually just did this to my buddy's car

Then I had a friend bump the starter of the car. He bumped it twice and it fell out to what you see there. This chain is actually pretty damn small.

the only thing I would change is that. Its much safer if u took a 19mm socket and breaker bar and turn the crank by urself. other than that great write up