Installing an Under Drive Pulley for the Infiniti VQ35DE
This instruction is specific to the VQ35 DE motor. Is to help guide you in the removal of the OEM pulley and installation of an aftermarket Under Drive Pulley.
First jack up the car, (in my case, the lift) and remove the wheel and access cover which is held on with 5 clips.
Here’s a tip: before you remove the belt, make a sketch of how it’s suppose to look like once you re-install the belt. We used the underside of the access panel.
The flash kind a distorted the pic but you can see the diagram we drew. It’s probably in the FSM.
When everything is exposed, you’ll see the crank pulley and to the left of that you’ll see the tension pulley. To the left of the tension pulley, you’ll see these two holes. You’ll need to lift up on the belt and swing the tension pulley to the left until you line up the holes. When they’re lined up stick a screw driver through the holes to keep the tension off of the belt.
If you have an impact wrench handy, use a 19mm socket to remove the pulley bolt. If you don’t, I’m sure you’ll be able to use a breaker bar but it’ll be easier if you have an impact wrench.
Once you have the bolt off, the pulley will come off. It it doesn’t, tap it with a hard nylon hammer around the pulley to loosen it up. The crank is keyed so you don’t need to remember the position of the pulley.
Now get the new pulley. Since it’s made by Stillen, I knew that the dimensions would be right on with the exception of the diameter size. But if you guys decide to buy a different pulley, make sure that the height dimension is equal to the OEM pulley.
Put the new pulley on and make sure the key on the crank is lined up with the key grove on the pulley. Gently tap it into place with the nylon head hammer. Hand screw the pulley bolt back on pulley
Now get the new belt and put it back on the way it came off. Use your handy dandy drawing you did on the access panel to help you… Make sure the belt is sitting into grooves of all the pulleys. If not, the belt will be shredded into pieces when you run the motor.
Remove the screwdriver that’s holding the tension pulley so the tension is re-applied. Use a sharpie to mark the pulley and the pulley bolt at the 9 o’clock position and just the pulley on the 12 o’clock position. These marks will serve as reference as you tighten the pulley bolt. When the bolt is tightened, the mark on the pulley bolt will get closer to the 12 o’clock mark you placed on the pulley.
Use a torque wrench to place 33ft-lbs on the pulley bolt. This is to “seat” the pulley flush before you secure it with an impact wrench. Remember, this will be spinning at high revolutions. You don’t want this to be seated crooked at those speeds! Use a screwdriver to “wedge” the pulley when you do this or else the pulley will just spin. You’ll notice the mark on the bolt is now between the initial reference marks.
Once you have the bolt tightened to the 33ft-lbs with the torque wrench, use the impact wrench to tighten it down further. Again this will bring the reference mark on the bolt pulley even closer to the 12o’clock mark.
Once you’re done with the pulley, put back the access panel with the 5 clips, and put the wheel back on. Lower the car and call it a day.