Eagle

Any Jeeps older than about 1990 are likely to produce questionable codes when you run a build sheet -- or just draw a blank. When Chrysler bought AMC, they didn't expend much effort entering historical build sheet data into their database. Also, many of the codes originally used in the early XJ/MJ years were subsequently recycled by DaimlerChrysler, so you may find yourself with a build sheet listing options that weren't available on ANY vehicle in the year your Jeep was manufactured. If you have an XJ or MJ that's still fairly original, there was often a build sheet either uder the driver's seat or behind the trim panel in the driver's door.

What do you plan to use it in? It's completely incompatible with either the Renix or Chrysler injection/ignition systems. This thing is what was used to replace the old points-and-condenser distributors from the 1960s.

That's true, if you're having a stroker crank custom machined, you can make the specs anything you want. Just be sure to verify everything and don't assume because the 2.5L and 4.0L are an essentially common design that all dimensions will be interchangeable. However, if you're looking at using stock connecting rods and stock pistons, that will set a few parameters and tend to preestablish where the top of the piston will have to be. Which may demonstrate that the crank dimensions have to fall within a narrow range -- or that "you can't get there from here."

I'm glad it was resolved so quickly. The initial post reminded me of a party I went to many years ago. I met a woman who was new to the area and whose profession was, shall we say (to avoid getting overly specific), one of the healing arts. And she commented that she wanted to start networking in the area, since she had just opened a new practice. I knew and associated with a number of professionals in her field and related fields, and so I started naming various groups I thought she might benefit from looking into for her networking.She stopped me quickly. "I don't care about those," she said, "I want to start my OWN network." I excused myself, and didn't even bother to apologize for wasting her time. When people say they want to "network" or "build community" and don't have any idea what networking or community building are ... there's only so much you can do.

When you next communicate with 5-90, tell him I said howdy. Jon should know (and perhaps you have already discussed) the reasons against using the 4.2L rods and stock pistons. First, the 4.2L rods are smaller and not as strong as the 4.0L rods. Second, due to minor dimensional differences between the 4.2L block and the 4.0L block, when you use the 4.2L rods and stock replacement pistons, you increase the compression significantly. This brings you to the need to consider quench height, compression, and cam overlap in order to control pre-ignition. You need a cam with enough overlap to bleed off some of the compression pressure to keep the engine from eating itself alive. Using the 4.0L rods, you can spec the pistons to give you the same deck height clearance as a stock 4.0L engine, and that gives you a stock compression ratio ... which avoids the pre-ignition problem. Getting back to the 2.5L engine, my source for the deck height information is the book Jeep Engines, which is put out by Chrysler. If you're going to build a Jeep engine, get this book. It has a Mopar part number: P5007161. Deck height for the 4.0L is 9.429 - 9.435 inches. Deck height for the 2.5L is 9.320 inches. However, the 2.5L is specified to run at 0 deck clearance (top of piston is flush with top of block). The 4.0L is specified to run with the top of the pistons at 0.0215" below the surface of the block. The connecting rods are, as you mentioned, the same length (and I believe the same part number). Although I have read that aftermarket pistons for both engines are the same part number, the specification is different. According to the book, the dimension from the centerline of the pin to the top of the piston is 1.601" for the 2.5L, and 1.651 - 1.655 for the 4.0L. Back to the drawing board ...

I agre with Pete -- I don't think there is any "standard" shock length for a particular lift height because a lot of guys fab custom mounts when they do an axle swap. For example -- Rancho specs call for a stock (0 lift) Comanche to use an RS9118 shock in the rear. The lengths for that shock are 11.625 compressed and 17.750 extended. That's a baseline. If you know you have a 3" lift and still have the stock mounts -- just add 3 inches. Once you go SOA and muck around with the mounts, you're pretty much in uncharted territory.

Is that the fault for a vapor leak? Take the O-ring off the gas cap, spray some silicone spray on it and rub it in, spray a bit more and work it in some more, and replace the cap. I did that on my wife's 2000 XJ last year and haven't had a code thrown since. They want something like $25 for a factory gas cap, which is ridiculous. I also found a place on-line that sells rubber O-rings and for c couple of bucks I bought a 5-pack of new O-rings. Next time I start to get vapor leak codes, if the silicone treatment won't cure it I'll just replace the O-ring.

XJ and MJ brakes are NOT symmetrical. The shoe sets include two long shoes and two short shoes. Specifically, the metal shoes themselves are the same, but two have longer strips of lining than the other two.

You don't have to accept it and live with it - just junk the antiquated drum brakes and install disk brakes. Simple! :beerhead: Probably two-thirds of the people who convert to rear discs don't even bother to hook up the parking brake, so I'm going to stay with my dinosaur attitude that there's no overriding reason or need to put rear disk brakes on a Jeep. Disc brakes are great for aircraft and racing vehicles, but for me it's just not worth the dollars or effort to make the conversion.

I am considering it, I need to find someone to cast a crank with the same throw out as the 4.2 crank. After that you can just use the 4.2 rods and oversized pistons. Should be able to get a 3.0L or so 4 cylinder out of it. Nope. It won't be that easy. I believe the deck height of the 2.5L is slightly lower than either the 4.0L or the 4.2L (and those two are not the same, which is one of the issues to be confronted when doing an I-6 stroker build). I suspect the preferred solution (and maybe the only solution) will be to use either 2.5L or 4.0L rods and custom cast pistons, with a special pin height.

It's not broken. This has been discussed several times in the past. Drum brakes do not hold as well in reverse as they do going forward. It's a function of the way the shoes and levers are arranged. In the old days, they were called "servo-assisted" brakes, The idea is that the forward rotation imparted to the shoes when they contact the drums tends to cam the shoes out and jam them harder against the drums, providing better braking. The same geometry also helps the parking brake hold when the nose is pointing downhill. It does NOT work in reverse. And it will not work in reverse. If you adjust your parking brakes so you get a good hold with the tail pointing downhill, they will be adjusted so tight that the brakes will be dragging and you'll wear them out in a very short while -- and probably ruin the drums in the process. It's just one of those facts of life we have to accept and learn to live with. Basically, don't park nose-up on steel hills, and ALWAYS use PARK or leave the tranny in first or reverse when parked -- don't EVER trust the parking brake alone.

My friend does still have his factory Stage 3 cam kit, new-in-box. He confirmed that he now has no use for it and he's willing to sell it to a Comanche Club member, but he doesn't know what to ask for it because he can't find any listings for that kit or any comparable kit from any of the cam companies. I do not wish to become a middle man in terms of negotiating, but I don't think he wants to join another forum at this point so he's not putting out a way to contavt him directly. If anyone is interested, send me a PM with an idea what you think is a fair price, and your e-mail address. If he thinks you price is in the ballpark, he can contact you and I'm out of the loop.

As an auto? For a 2WD ==> 4WD conversion? Any auto tranny + transfer case set out of any XJ or MJ 2.5L. But ... the transfer cases used from 84 through 86 were not as good as the 231, so you'll be better off looking for boxesout of 87 through 2000 XJs, and 87 through 92 MJs. Just get the tranny and transfer case together and you have no worries about input shaft compatibility. You can't bolt a transfer case to a 2WD tranny without converting the tailshaft anyway, and those parts cost money. It's better just to buy the whole enchilada.

There are camshafts. The factory used to offer three levels of performance cam kits through the Mopar Performance Catalog. A friend of mine in NAXJA bought one of the Stage 3 cam kits for his 2.5L MJ. I believe he later sold the truck without ever installing the cam. If anyone is interested, I can ask if he still has the cam kit and, if so, if he's interested in selling it. I believe Clifford Performance & Research offers cams for the 2.5L, as well.

Except that in stock form, most SUA springs have significant arch and most SOA springs sit basically flat. And XJ springs don't have arch. If anything, the rear tip arches DOWN, not up. They are, for all practical purposes, flat when installed in a vehicle, and that's what counts regarding which way the eye has to move when the suspension compresses or droops.

It wasn't a recall, but there was a TSB (Technical Service Bulletin). Apparently there's significant enough current losss in the factory harness that Jeep came out with a separate, stand-alone harness that runs directly from the CPS connector through the firewall into the ECU. The harness should still be available from Jeep dealers.

Front axle u-joints? Rear drive shaft u-joints?

Mine has 285,000 on it.

They WERE clearcoated. Once the clearcoat gets compromised, it traps moisture underneath and promotes oxidation. When that happens, the only approach is to strip the clearcoat, polish, and then decide if you want to try spray-on clearcoat in a can, or accept that you'll need to polish periodically. I use Aircraft Stripper (that's a brand name) from Auto Zone. Like the one mentioned above, I believe it's acidic and should not be left on too long. I do it at a coin-op car wash on a day when they're slow. Put the wheels on the floor near the drain, paint of the stripper with a cheap chip brush from Lowe's or Home Depot, let it work for a minute or two, then fire up the car wash and wash it off. If it doesn't get completely stripped, I repeat as necessary. A pressure washer at home would do the same thing, but (a) I don't have a pressure washer, and (B) I'm on a well, which is near my driveway and garage, and I don't feel like dumping a bunch of somewhat nasty chemicals into my water supply. I don't recoat. I might try one wheel as an experiment, but once they're stripped it isn't too hard to polish them occasionally.

Ever look at an XJ spring? It's flat. MJ springs are arched. It DOES make a difference.

Well, maybe you Cheyennes don't smoke "that stuff whose name begins with 'P'," but there are sects within some of the southwestern tribes that do. "That stuff" is specifically exempted from Federal and state drug laws when used for ceremonial purposes for a reason. The notion that there is ONE flavor of "Native American spirituality" when there are (or were) something like 385 distinct tribal groups in the continental United States alone is sort of silly.

Rancho doesn't list a 3" AAL for a Comanche. What AAL did you use?

Looks that way to me.

It depends on whether it's spring under or spring over, and how flat the springs are. For a typical spring-under, like a stock MJ, there's a lot of arch in the spring. The shackle should be basically vertical, because when the spring compresses it gets flatter and longer, and when it droops it needs to pull the shackle forward. In a SOA like a stock XJ, the spring is basically flat at rest. It can't get any longer, so the shackle can/should point back. The spring arches more and gets shorter whether the suspension compresses or droops, so the shackle will never need to swing farther back.

As often is the case, "it depends." There's no difference between a 231 for an automatic and a 231 for a 5-speed. But ... if she's looking to convert a 2WD into a 4WD, she needs a 4WD tranny. You can't bolt a transfer case to a 2WD transmission with changing the tailshaft and the tailshaft housing. Secondly, the early 231s had a 21-spline connection between the transmission and the transfer case. The later ones used 23 splines. I can never remember when the change took place -- somewhere around 1990, I believe. So in order to provide a better, more definitive answer, we need to know what she's trying to do. If she's just replacing a busted transfer case -- no problem as long as the "new" one comes from the same "generation." If she's doing a 2WD to 4WD conversion, it's more complicated.