Underdrive Pulley Installation: 4.0 SOHC Motor

[Hitchhikingmike]

I'm referring to the three/ four bolts that screw into the pulley itself that you pull on to remove the pulley, not the center bolt on the crank.

I am having trouble determining the size of the bolts needed to screw into the pulley itself, not the crank.

 

[Hitchhikingmike]

Found the right bolt size: two quantities of Metric size 8mmx1.25x100 (4" long) approximately. I will have to wait for the bolt specialty store to open Monday to pick up the two bolts so I can resume the project next weekend, as my puller kit does contains the right bolt, but just not long enough to work (about 1/2" too short).

I finally discovered that not all holes in the stock pulley are the same. There are a total of four, each of the same size in bore, and equal distant from each other, however they are not all threaded to the same size and pitch. 8mmx1.25 threads into two of the holes, I don't know what fits into the other two holes, metric 8mmx1.25 certainly does not.

That is what was throwing me off the entire time- the two different size threaded holes. I was just fitting my bots into one hole, not trying all of them as I just did today.

Let this be a reference for anyone else whom undertakes this task who has the different type of harmonic balanceer on their 4.0 than Aldive's in his picture.

I will post a picture of my stock pulley once I get it off to show the difference.

 

[Hitchhikingmike]

Okay, I just got the UDP installed. Turn out the two long skinny bolts that ASP shipped with the UDP pulley were the correct size after all. I was just sticking them in the wrong hole, as I mentioned before. Boy, I can do well in Cal 1&2, and both of my other engineering classes, but I couldn't figure out which hole the bolt goes in!

 

[Ronin8002]

Glad you got it figured out...apparently I had the same problem and never picked up on it So maybe Cal 1 & 2 are doing more for you than you realize

 

[Hitchhikingmike]

Just for reference, here is the second type of factory harmonic balancer that exists, different from Aldive's. Only two of the holes are threaded for 8mm metric bolts.

left-UDP; right- stock pulley
Perhaps this was a 3rd gen specific change?

EDIT: see the link below for my registry. Scroll to the bottom of the thread for pictures of my installation.

 

[CDW6212R]

I think so, that is also bigger than the 97-01 part.

 

[ranger7ltr]

This is the balancer from my 99 OHV...

I don't think the one on the right is any larger than my new balancer...

 

[ranger7ltr]

Is the UDP from ASP also for pre 02 4 liter?

Just for reference, here is the second type of factory harmonic balancer that exists, different from Aldive's. Only two of the holes are threaded for 8mm metric bolts.

left-UDP; right- stock pulley
Perhaps this was a 3rd gen specific change?

EDIT: see the link below for my registry. Scroll to the bottom of the thread for pictures of my installation.

I have been kinda following this and just wonder if the ASP part would also fit an earlier engine...I looked at their site and they don't even list anything for the Explorer... I think a call is in order this week...

 

[Hitchhikingmike]

The UDP that ASP manufactures is the same for both the v6 OHV and SOHC. I further suspect that both engines also share the same circumference stock harmonic balancer as well.

 

[CDW6212R]

It just looks bigger, the belt will need work.

 

[rokr1292]

Very helpful, finally got myself the truck I wanted, but with gas getting more and more expensive again, going from a 2.3 ranger to a 4.0 sport trac was a bit of a wallet shock. What is the approximate net mpg increase from just the crank pulley install?

 

[Hitchhikingmike]

Well, with just me in the truck cruising down the highway @ 65mph I can get about 24mpg.

 

[iBangKaty]

where can i buy under drive pulley's?????

 

[Ronin8002]

where can i buy under drive pulley's?????

I think Zabteck or Henson Performance might still sell the crank pulleys. Not sure if you can get the other ones anymore. Try some of the 4.0 SOHC mustang forums...they'll know for sure.

 

[kindred4x]

James Henson at Hensonperformance.com sells the pulley. I just put one on my truck and am very pleased with it. The best bolt on I have done to my truck