UNDERDRIVE PULLEYS INSTALL
Written by Mustangworld.
Here we will show you how to install a set of underdrive pullies on the
4.6L. The installation is similar on the 4.6L DOHC or Cobra engine.
a set of March pullies. Some nice things about this set is the fact that
all three pullies are billet aluminum for great weight savings and less
rotational mass for each pulley. They cost $129. Also, the alternator
pulley is only 1/2 a centimeter larger than the stock alternator pulley
for NO CHARGING PROBLEMS !!!! We've been waiting for this feature from
several kits we've seen and used. On the 5.0 this was difficult with the
tensioner almost at full stop, but on the 4.6L, because of it's belt design
and accessory locations, you can make up for the underdrive crank almost
entirely at the water pump. You don't even need to change the alternator
pulley, but we did just to show you how (it's easy).
engine crank is INTERNALLY BALANCED (SOHC / DOHC) so there is no harmonc
balancer to worry about (like on the 5.0) , BUT the external crank pulley
on the 4.6L also acts as a vibration dampner, there is a thin rubber ring
to absorb any extra vibration on the stock crank pulley. So you will still
need to bolt your stock crank pulley to your new underdrive to have this
extra dampening. You will need to use a special harmonic balancer pulling
tool to remove the stock crank pulley
is the correct plural spelling VS "pullies" ;-).
go ! Disconnect the battery before starting:
Here is the March set of all billet machined pulleys
(all three). You get an alternator, water pump and crank pulley.
They come with a new crank shaft bolt and hardware. Cost $129
for the kit.
Here are your stock pulleys. The alternator, water
pump, and crank pulley are the ones we'll be changing out.
Here is the Alternator pulley. It's held on with
one large nut. It will need to be removed with an special impact
Here is your water pump pulley. It is held in place
with 4 bolts. You can use a wrench to remove it.
Here is your crank pulley. It is held in place
with one bolt. You'll need a large wrench, 18mm socket and a harmonic
balancer pulling tool to remove it.
Here is a shot if the harmonic balancer pulling
tool. You'll need this to remove the crank pulley in the 4.6L.
They cost around $4 - $150, depending on features. You can't do
this install without it.
remove all the bolts, leave the belt in place and loosen all
the bolts. Here we used our air impact wrench. Took 90 seconds
to loosen up the crank, water pump and alternator. If you don't
have an impact wrench, you'll need to do all of this manually.
Everything can be done manually with the exception of the alternator
pulley nut. YOU NEED to use an impact wrench for this (for install
ease). See the next step.
For those with no impact wrench, no problem, remove
your alternator and take it down to your local Chief, Pep-boys,
etc.. They will remove and install your new underdrive pulley
(most for free!) in about 60 seconds ! No problem. The alternator
is held in your stang by 3 bolts, one on top, 2 on the bottom.
Also disconnect 2 wire clips and one ground wire, then remove.
Take the new pulley WITH THE SPACERS down to the
shop with your alternator (or not if you are doing this at home).
NOTE: You will need to use the large spacer to have the new alternator
pulley running in the belt line. Put both the stock alt. pulley
and new underdrive pulley on a table and check to see how they
line up. You'll want EACH GROOVE on the pulley to line up. Forget
about lining up the edges of the pulleys, it's the belt grooves
that need to line up.
After you've loosened all the pulleys (nuts and
bolts), you can then put a wrench with no socket into the belt
tensioner and move it up to remove the belt. Now remove the water
pump pulley, and keep it off. Make sure the crank bolt is also
removed. Then using your harmonic balancer puller tool, carefully
remove the crank pulley / balancer. The 4.6L is internally balanced
so this is actually only a dampener. See above notes about this.
Here's a better view of the crank / balancer pulley
removed. By turning the balancer removal tool's center bolt, it
"pulls" the crank pulley right off. Make sure you have
one hand on the pulley so it does not fall to the floor during
removal. We say "balancer" because folks won't know
what we're talking about if we called this a "dampener".
The 4.6L has no harmonic balancer, the crankshaft is internally
Up close you can see the rubber vibration dampening
material around the outside of the crank pulley. This is why it
is also referred to as the "dampener".
Again: On the 5.0 the crank pulley is separate from the harmonic
balancer / dampener. On the 4.6L the crankshaft is internally
balanced, but the external crank pulley also acts as an auxiliary
"dampener". This confuses many Mustang enthusiasts,
so we want to make this clear. Also note the "Notch"
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