I had some time this evening, so I went ahead and did the March underdrive pulley swap on my 84. Another simple job - I love it.

The two issues I did run into though were that without an impact there is no way to remove the alternator pulley. For now I just left the stocker on there. The other was that the belt the say to use was WAY too long. They say to use a Dayco 5060870 and I ended up having to get a 5060850. Before you go saying "yeah, but you didn't do the alternator pulley and it's larger in diameter, so that would be the difference.", no that small bit of diameter would definitely NOT have made the difference. Even with the much shorter belt, the tensioner is about halfway through its arc - there is still plenty of room to get up to the point where the belt would be too short.

As soon as I can drop by my buddys (who has air tools) I can swap off the alternator pulley in 5 minutes.

As for performance, it does pull better in the upper end. Funny thing is, it just seems to be smoother all around. That doesn't really make much sense, but that's just my first impression.

For those who have never done this, all you need for the bottom pulley are a 14 and 16mm standard (not deep) socket. The alternator pulley nut seems to be 24mm, but it might be an English size nut, or mine may have been replaced with something English sized at some point. Also, there is a square hole right by the idler pulley on the front of the aluminum casting. That hole is meant for a 1/2" breaker bar. Just snap your bar into the hole and then pull to release the tension on the belt.

A WORD OF WARNING! If the tensioner snaps tight and your finger is between the belt and a pulley, expect it (your finger!) to get broken. The tensioner has a LOT of spring tension there so NEVER get your finger between the belt and the pulley.

 

I dropped by Mike's tonight and swapped out the alternator pulley.
A 1" impact socket fit perfectly.
The belt is just the right length.
The charging is just fine.

I had a chance to get on it once afterwards on a nice flat pice of road and I got my first 2nd gear chirp (with the trans shifting on its own). It wasn't huge or anything, but it was a chirp nonetheless. I'm a happy camper!

 

Did you get the 3 piece Aluminum March Power and Amp pulley set or the Steel set?

Also, is the Alternator voltage 13 volts or higher? Thanks

 

I got the 2 piece kit and the voltage is above 13.

 

I have the March 3 piece painted aluminum Power and Amp set. My start up voltage is around 14.3 volts. After warm up, with air and radio on, it drops to @ 13.9 volts. The stock # is 4425. They don't make the painted one for the 1984, it fits 1988-1991.

 

I'd be interested in the diameters of the pulleys you installed.

Thanks

 

If you are talking to me the set for a 1986 is different from my 1989.
www.marchperf.com has lots of info.

 

I'll see if I can throw a tape on to be accurate, but the lower pulley is about 1 1/2" smaller in diameter and the alternator pulley was about 3/8" larger.

Again, this is the black powder coated set for the 84.

 

I have the 2 pulley set on my 85. It was installed when i rebuilt my motor along with a bunch of other mods, so I cannot attest to any improvement, but no ill effects. It has been 3 years now.

 

MCM, is that your wife, girlfriend, daughter or just a random chick? Either way, bravo!

 

Thanks man, that's my wife: http://www.marcmedina.com/wedding.html

 

Hey man! That's awesome, loved the link! It looks like you had a great experience...

 

The wedding was great, and everything since has been great too!