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.

These are 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).

The 4.6L 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

BTW "pulleys" is the correct plural spelling VS "pullies" ;-).

Here'we go ! Disconnect the battery before starting:

1. 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. March Pulley Kit.
2. Here are your stock pulleys. The alternator, water pump, and crank pulley are the ones we'll be changing out. 3 Stock Pulleys
3. Here is the Alternator pulley. It's held on with one large nut. It will need to be removed with an special impact wrench. Alternator Pulley
4. Here is your water pump pulley. It is held in place with 4 bolts. You can use a wrench to remove it. Water Pump Pulley
5. 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. Crank / Balancer Pulley
6. 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. Harmonic Balancer Puller

7. To 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.

Impact Alt. Nut off.
8. 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. Remove Alt. If needed
9. 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. Pulley spacers
10. 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. Balancer Puller
11. 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 balanced. Crank w/balancer attached
12. 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" key ! Crank close up
Continued on the NEXT PAGE ---->


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