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Here's another write-up:
http://www.b15u.com/sentra-specific.../16792-qr25de-free-balance-shaft-removal.html
Here's the JWT write-up for their kit:
http://www.b15u.com/sentra-specific...emoval-bsr-kit-installation-instructions.html
_________________________
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
This image has been resized. Click this bar to view the full image. The original is 800x600.
![]()
This is what you start with. Luckily for me I had access to an automotive lift.
This image has been resized. Click this bar to view the full image. The original is 800x600.
![]()
First comes first. Drain your oil. This is the 14mm wrench's only job.
This image has been resized. Click this bar to view the full image. The original is 800x600.
![]()
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.
This image has been resized. Click this bar to view the full image. The original is 800x600.
![]()
All bolts removed.
This image has been resized. Click this bar to view the full image. The original is 800x600.
![]()
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.
This image has been resized. Click this bar to view the full image. The original is 800x600.
![]()
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.
This image has been resized. Click this bar to view the full image. The original is 800x600.
![]()
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.....
This image has been resized. Click this bar to view the full image. The original is 800x600.
![]()
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.
This image has been resized. Click this bar to view the full image. The original is 800x600.
![]()
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.
This image has been resized. Click this bar to view the full image. The original is 800x600.
![]()
This image has been resized. Click this bar to view the full image. The original is 800x600.
![]()
This image has been resized. Click this bar to view the full image. The original is 800x600.
![]()
Ready for remounting.
Mounted and ready for oil.
This image has been resized. Click this bar to view the full image. The original is 800x600.
![]()
Don't forget to change your oil filter.
Refill with oil when you're ready.
The large oil mess all over the floor.
This image has been resized. Click this bar to view the full image. The original is 800x600.
![]()
The large oil mess all over me. I got this shit on my face and lips.
This image has been resized. Click this bar to view the full image. The original is 800x600.
![]()
Spare parts.
This image has been resized. Click this bar to view the full image. The original is 800x600.
![]()
http://www.b15u.com/sentra-specific.../16792-qr25de-free-balance-shaft-removal.html
Here's the JWT write-up for their kit:
http://www.b15u.com/sentra-specific...emoval-bsr-kit-installation-instructions.html
_________________________
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
This image has been resized. Click this bar to view the full image. The original is 800x600.
This is what you start with. Luckily for me I had access to an automotive lift.
This image has been resized. Click this bar to view the full image. The original is 800x600.
First comes first. Drain your oil. This is the 14mm wrench's only job.
This image has been resized. Click this bar to view the full image. The original is 800x600.
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.
This image has been resized. Click this bar to view the full image. The original is 800x600.
All bolts removed.
This image has been resized. Click this bar to view the full image. The original is 800x600.
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.
This image has been resized. Click this bar to view the full image. The original is 800x600.
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.
This image has been resized. Click this bar to view the full image. The original is 800x600.
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.....
This image has been resized. Click this bar to view the full image. The original is 800x600.
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.
This image has been resized. Click this bar to view the full image. The original is 800x600.
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.
This image has been resized. Click this bar to view the full image. The original is 800x600.
This image has been resized. Click this bar to view the full image. The original is 800x600.
This image has been resized. Click this bar to view the full image. The original is 800x600.
Ready for remounting.
Mounted and ready for oil.
This image has been resized. Click this bar to view the full image. The original is 800x600.
Don't forget to change your oil filter.
Refill with oil when you're ready.
The large oil mess all over the floor.
This image has been resized. Click this bar to view the full image. The original is 800x600.
The large oil mess all over me. I got this shit on my face and lips.
This image has been resized. Click this bar to view the full image. The original is 800x600.
Spare parts.
This image has been resized. Click this bar to view the full image. The original is 800x600.
