Serpentine Conversion with no AC

Serpentine Conversion with no AC


Philadelphia, PA
1986 CJ-7 - 258 - D300 - Factory 44 Rear, 2002 BMW M5
To make it short and sweet for anyone not wanting to read my long-winded intro I'm just asking if the title is possible. Can a v-belt drive 258 with only p/s and alternator be converted to a serpentine accessory drive or is it necessary to have an AC compressor even if it's not used?

I've looked around for some info and it seems that most people who do the swap using junkyard parts just grab everything off of an XJ which is probably hard to find without AC. I know the CJ's had both v-drive and serpentine systems on the 258 but was that dictated by whether or not it had AC?

For anyone who would have skipped it here's my intro as I'm new to this forum. I have an '86 CJ7 which was my first car. I bought it not-running for $500 the day I got my driver's license. Traced the problem to two broken pushrods and replaced them with new rocker arms. I drove it my senior year of high school and my first two years of college until oil blow-by finally made me crack and get a rebuilt motor to put in. I did the work myself and drove it about another 4 years until it spun a bearing. I've since owned other daily drivers and couldn't bring myself to let go of the Jeep as I knew I would want it when I had the time and money to put into the repairs. It sat from 2004-2009 until I began to bring it back to life. The Jeep is running again and I will be replacing the crank and bearings after this snowboarding season. I plan to do an MPI conversion and maybe the 4.0 head swap as well once I have it in roadworthy condition again and am driving it but one thing I would like to do is convert to a serpentine accessory drive and it doesn't have nor do I want AC. Is this possible without an AC compressor or would I need one that just isn't connected? Or should I just deal with the two v-belts?

I know I'm new to this forum but I am very mechanically inclined. I worked as a tech and a service advisor through high school and college. And I perform all the work on every car I've owned. My current daily driver is a BMW M5 and I'm the only one who takes a wrench to it. I bought the Jeep as my first car because of this mentality and at that time I didn't have the knowledge base I have now so I wanted something simpler in design so I could do all the work myself. I know a good deal about it but I'm sure not nearly as much as most of the people on this board. I look forward to getting to know everyone here as I resurrect my old friend and observe and learn from your own projects as well!
Hello Strike.

I do not know about the air conditioner part of the swap but you have to change the water pump to a reversed rotation pump due to the routing of the serpent belt. When I added power steering the serpent belt was very close to the upper water hose. I found that here several auto stores did not know anything about the reversed pump and did not believe it. Good luck.
If you do the 4.0 mpi do the head swap. There are many reasons for that but the one that comes to mind first is the intake runners. The 4.0 runners are at 45 deg angles and the 258's are dog legged at 90. The injectors are angle to match that angle and if you don't change the head you are essentially trying to squirt around a corner.

On the serp, I can only speak on the year I did. I got everything of a 91 xj. I got all the brackets and components. The only modifications I had to makewere to mount the alt bracket. There was an eyelet at the bottom of the block under the timing cover that I had to cut off to clear the braket. Then I had to drill out one of the bolt holeson the timing cover to fit one of the mounting bolts through. The alt bracket actually mounted to two places on the timing cover and 2 tapped holes on the block. The 258 didn't have the bolt holes on the block so I just used the timing cover. The alt is static so I think two is sufficient.

You would have to find a donor without ac if you were that against it. I just use the compressor as a place holder. you could always turn it into an onboard compressor.

other issues to consider...
xjs have an off center, smaller mech fan with a small electric fan that kicks in for ac or if the mechanical fan Can't keep the temp down. So if you used an xj donor you may want to look into a.electric fan from a contour or Taurus.

If you do not do the.serp in conjuction with. 4.0 intake, I do not think the 258 intake has the.same ps pump bolt pattern so you would have to figure out how to get.the.4.0 bracket to mount or.figure out a if a serp pulley will mount to the original ps pump.

You will need a spacer for the harmonic balancer. The 258 snout is longer. hesco sells these or you can cut down your old balancer into a spacer.

Finally, the alt in 4.0 s are not dependant on rpms to make their max output like our stock alternators. If you do this get your alt from a grand cherokee with 4.0. These come stock with a 133 amp alternator. If you can't find a gc to pull from an xj is. Good second choice.

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