I honestly have no idea why some have v-belts and some have serpentine belts. My '90 with the 4.2 has serpentine belts and was likely originally sold in CA. There has been speculation on here in the past about factory A/C vs non A/C but I have two friends with '89's and one has a serpentine and one has v-belts and neither have A/C. As far as I know there were no special anti-smog devices added to "CA models" I don't think there's a difference between the two other than water pump rotation.

 

I cant answer your question either but I can say that I have two 89s with v belts. One is a base model 2.5 and the other is a Laredo with the 4.2

 

Because v-belts are an older technology that started falling out of favor during the time the YJ was being produced. Serpentine belts are a better technology. Jeep wasn't the company that let parts sit around in warehouses after changing a production line. They used all of the old parts during the switchover.

 

The serpentine belt has more surface area per pulley therefore more ‘traction’ than a v-belt. As AC become more standard and things became more compact overall, the quest for reducing ‘unnecessary’ weight to improve gas mileage also began. As a plus they could engineer simple, single point adjustment which reduced manufacturing costs(less parts.)

Chrysler absorbed AMC as the YJ run began. Although the YJ was “simpler” than a car, Chrysler began making running changes rather than stay with the AMC configurations to homogenize parts-binning. The v-belt pulleys were obsoleting while the serpentine pulleys were shared among a number of models. Things like the (denso?) alternator from Chrysler contracts were enabled rather than stay with the GM alternator…

There are as no legal mandate to change so they just made the change when fulfilled parts orders were depleted.
A number of carbureted six cylinder serpentine engines were assembled; I don’t think I’ve see a 2.5 tbi with a serpentine belt. Dunno.

 

Thanks for info guys. My rig did not come with factory air and when looking at my options, there is a difference in the a/c units between the two, it seem to be more than just the pulley, some only work with a v belt and some mention the California serpentine so I just was wondering if there were two different serpentine options. Doesn't sound like it though, right?

 

There were two different AC compressors

I don’t know if a/b was coincident with vbelt/serp

 

I don't know how the A/C is driven on either but it's possible the rotation would be different like the water pump. Also don't know if that would even matter on an A/C compressor.

 

 

Okay, thanks. I'll have to some more research before I pull the trigger.

 

FWIW. my 1990 came with factory a/c, serp belt and originated in Massachusetts. as far as I know everything had a sanden style compressor after the old old 60s version cherokee with a york went away. I suppose you could change all the pulleys but seems like a lot of work for no real benefit. I do know with the a/c in place there is not much belt contact with the alternator pulley and there is slippage under load, at least for me

 

Jbolty, any chance you could snap a picture of your setup and post it or PM me?

 

Are you looking for the routing? I swapped in a York compressor and custom bracket years ago but the spin directions are all the same

 

This is my 4.2 out of an 83 cj8. Original motor and the jeep originated in Cali. Hope the pictures help.

 

That's not the same set up as a YJ serpentine....

Looks like you've got an extra idler on the driver side. Odd that as far back as '83 they were running serps but didn't continue.

 

Yes, I was looking for how the belt went around everything and where the a/c pump was placed. I see from the pics from here and other posts that it goes above the alternator. Thanks for all the help everyone, I think I have what I need to figure out what I'm going to do.

 

:rofl::rofl::rofl:

Makes sense.