This is just a quick write-up of my swap from v-belts to a serpentine belt on my 87 YJ 4.2.
Cliffs: 4.2 YJ serpentine swap using 2.5 Comanche parts
Why? A couple reasons for me. First, my stock accessories never seemed to line up very well. The PS pump was set back too far so I lost a few belts on the trail in the last couple years. Second, my alternator was a PITA to tension and the bracket flexed a bit so it would always have issues squeaking under load. This also gives me more options with the PS pump and an external res for more fluid. I always had issues keeping steering fluid in the res since adding hydro assist so that is taken care of now.
Now for the how. I've seen several pictures of CJs and YJ (4.2) with a serpentine belt, but they all either had AC, or a goofy idler setup on top where the AC compressor should be on a non-AC Jeep. Hard to find parts isn't what I wanted.
I hit the junk yard to check out some 4.0 Cherokees which are always abundant to see if the parts could transfer over. After checking a few I saw that the PS pump bolted through the bracket to the manifold, and my 4.2 manifold didn't have the proper casting for that. I also wasn't sure the lower alternator bracket would match my block.
I checked a few more and came across a Comanche (88) that looked very interesting. It was a non-AC truck, and to my memory it appeared the brackets for power steering and the alternator matched my motor. I started pulling the parts off and was about 1/2 way through when I noticed this was a 2.5L 4cyl. I took a quick walk to see if there was anything with a 4.2 in the yard (there wasn't) and came back to the Comanche. I was pretty sure the parts were right, so it finished pulling everything and headed out.
I don't have a great before pic, but this should give an idea. Standard v-belt setup
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I stripped off the original alternator and power steering brackets and got to work fitting the new brackets. By fitting, I mean bolting on. Everything matched up to my 258 perfectly.
Pump bracket. 2 bolts into the intake manifold, and 2 into the water pump
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Alternator. 3 bolts into the block and 2 through the timing cover.
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After my successful mock-up with the new brackets, I went ahead with the swap. New balancer, new water pump, new alternator, and new PS pump. The steering pump and alternator are both spec'd for the 4cyl Cherokee. I found a 93 Grand AM GT uses the same alternator, and there are high amp options available as well. I also happened to have the required adapter for the alternator plug from years ago when I was planning to swap my alternator and never did. This is NAPA p/n ECH EC82.
For the belt, I figured it would use the standard belt from the 4cyl, but the parts stores list a 73-1/2" belt. This was too long so it did some searching and ended up with a K060703 belt which is 70-7/8" long.
Here is the end result. I didn't think to take pictures until I had the radiator back in, but here are the finished pics.
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I know not a lot of people bother to spend the time or money swapping the belts like this. I searched a bit before I started and I was surprised I didn't find any previous mention of using these brackets on a 4.2. Since Jeep obviously had the brackets, I'm also surprised they never used them from the factory. Maybe this will help someone else of with a future project.
Enjoy
Cliffs: 4.2 YJ serpentine swap using 2.5 Comanche parts
Why? A couple reasons for me. First, my stock accessories never seemed to line up very well. The PS pump was set back too far so I lost a few belts on the trail in the last couple years. Second, my alternator was a PITA to tension and the bracket flexed a bit so it would always have issues squeaking under load. This also gives me more options with the PS pump and an external res for more fluid. I always had issues keeping steering fluid in the res since adding hydro assist so that is taken care of now.
Now for the how. I've seen several pictures of CJs and YJ (4.2) with a serpentine belt, but they all either had AC, or a goofy idler setup on top where the AC compressor should be on a non-AC Jeep. Hard to find parts isn't what I wanted.
I hit the junk yard to check out some 4.0 Cherokees which are always abundant to see if the parts could transfer over. After checking a few I saw that the PS pump bolted through the bracket to the manifold, and my 4.2 manifold didn't have the proper casting for that. I also wasn't sure the lower alternator bracket would match my block.
I checked a few more and came across a Comanche (88) that looked very interesting. It was a non-AC truck, and to my memory it appeared the brackets for power steering and the alternator matched my motor. I started pulling the parts off and was about 1/2 way through when I noticed this was a 2.5L 4cyl. I took a quick walk to see if there was anything with a 4.2 in the yard (there wasn't) and came back to the Comanche. I was pretty sure the parts were right, so it finished pulling everything and headed out.
I don't have a great before pic, but this should give an idea. Standard v-belt setup
I stripped off the original alternator and power steering brackets and got to work fitting the new brackets. By fitting, I mean bolting on. Everything matched up to my 258 perfectly.
Pump bracket. 2 bolts into the intake manifold, and 2 into the water pump
Alternator. 3 bolts into the block and 2 through the timing cover.
After my successful mock-up with the new brackets, I went ahead with the swap. New balancer, new water pump, new alternator, and new PS pump. The steering pump and alternator are both spec'd for the 4cyl Cherokee. I found a 93 Grand AM GT uses the same alternator, and there are high amp options available as well. I also happened to have the required adapter for the alternator plug from years ago when I was planning to swap my alternator and never did. This is NAPA p/n ECH EC82.
For the belt, I figured it would use the standard belt from the 4cyl, but the parts stores list a 73-1/2" belt. This was too long so it did some searching and ended up with a K060703 belt which is 70-7/8" long.
Here is the end result. I didn't think to take pictures until I had the radiator back in, but here are the finished pics.
I know not a lot of people bother to spend the time or money swapping the belts like this. I searched a bit before I started and I was surprised I didn't find any previous mention of using these brackets on a 4.2. Since Jeep obviously had the brackets, I'm also surprised they never used them from the factory. Maybe this will help someone else of with a future project.
Enjoy
