Eagle

^^^ Agreed. The heater isn't "cutting out." It's "redirecting." The flappers that control air flow are operated by vacuum. One of the functions of the vacuum canister (the "football" or the "blimp") behind the right corner of the front bumper is to maintain vacuum when the engine is under load, such as going uphill, so the ventilation controls operate normally. The default position for the vants in the dashboard is the top-of-dash defrost outlets, so when you lose vacuum the air flow switches to those. When the vacuum comes back, the airflow reverts to wherever you had it set for. Either your vacuum reservoir is cracked (or missing), or you have a vacuum leak.

^^^ Agreed. The heater isn't "cutting out." It's "redirecting." The flappers that control air flow are operated by vacuum. One of the functions of the vacuum canister (the "football" or the "blimp") behind the right corner of the front bumper is to maintain vacuum when the engine is under load, such as going uphill, so the ventilation controls operate normally. The default position for the vants in the dashboard is the top-of-dash defrost outlets, so when you lose vacuum the air flow switches to those. When the vacuum comes back, the airflow reverts to wherever you had it set for. Either your vacuum reservoir is cracked (or missing), or you have a vacuum leak.

Dunno how I missed this thread on Monday, but at least I was able to come in when it appears there may be hope on the horizon. Your knowledge of the brand and your dedication are much like that of the parts guru at my local dealership. I really hope this interview goes well for you. Good luck.

My '87 has the roll bar lights. Switch is in the bezel to the left of the steering column and uses the same icon as the fog lights. Mine does not have fogs, so I don't know what they did if you got both.

But he asked about long block. The 2.5L got the TBI starting in 1986, a year before the 4.0L came along, and like the 4.0L went to the Chrysler injection system starting in 1991. So the direct swaps for an '87 would be 1986 thru 1990.

You may indeed have multiple things going on. By all means, start with the thermostat, since the evidence of the hoses is what they call a "clue." The other thing to look for is if it heats up quickly when you're stopped, and then cools back down toward normal as soon as you get rolling again. That indicates that the viscous fan coupling on the mechanical fan isn't doing the job, and at rest the fan isn't pulling enough air through the radiator to cool the system. Once you're rolling, vehicle motion forces air through the radiator, so the temp drops back down.

First, how much sag is there, and how are you measuring it? Best approach if you really have sag is to get another set of XJ springs, cut the eyes off the main leaves, and use them as add-a-leaves. I did that on an '88 XJ I was refurbishing for an ex-GF. The rear had sagged a half inch (measured from axle centerline to flares). The addition of a pair of cut-off main leaves gave me a gross lift of 1-1/4". Because I had started out a half inch low, the net gain was a 3/4" lift over stock height -- which is less than the factory Up Country option. The ride was very good. Short AALs that try for a lot of lift are very choppy and harsh, but I've met several people who have used cut-off main leaves as an AAL and all agreed that the resulting ride was very comfortable.

I can't imagine why anyone would prefer digital instruments over analog. Especially for the speedo and important gauges like temperature and oil pressure. With a digital readout, you actually have to take the time to read it to know if you're in the safe or normal zone. With analog instruments, once you have driven the vehicle for awhile you brain knows where the needle is supposed to be. All you have to do is glance at it. If the needle is in the normal position ... that's all the input that's necessary and the brain just says, "Okay, look att he road, Dummy." If the needle is NOT in the normal position, the brain then says. "Hey, we might have a problem here. Better check it out." Digital instruments, in automobiles or in aircraft, are a non-solution to a non-existent problem. They don't accomplish anything an analog dial doesn't accomplish, and they create a more dangerous operating environment.

Oh yes I do.

10-4. That's why I don't have ABS even on the newer Cherokees, when it was available at the time I bought them. If I had known I was going to remarry and turn the 2000 XJ Classic over to my wife, I would have ordered it with ABS. But ... it's configured the way I wanted it for me (except it has automatic, since the 5-speed wasn't offered in the Classic).

More than likely, you'll open it up and find that when your son tried to force it, one of the forks jumped over a slot and got stuck. I doubt anything is broken -- you'll just need to realign everything correctly for neatral and button it up again.

Um ... your signature says you have an 87 and an 89, but your post is asking about an open cooling system. Have you converted, or do you have the terminology mixed up?

Personally I hate ABS, but I wish I had it for my wife. However, especially in a pickup, the rear is what's probably going to lock up first. IF I were going to put ABS on only one end of a pickup, I'd put it on the rear rather than the front.

Correction - it includes some of our 4.0L engines. The Renix system has a knock sensor. Chrysler deleted the knock sensor when they changed over to a Mopar injection/ignition system in model year 1991. No XJ or MJ 1991 or newer has a knock sensor.

As a few of you already know, while I am a life/charter member of NAXJA, I have had my differences with them and I much prefer to hang around on this site. However, I feel I have to respond to this comment. NAXJA was never EVER conceived of as or intended to be a totally freebie web site. NAXJA from its very inception was a "club," with dues and "memberships." And membership expired if you didn't pay your dues. The web site and forum were not the sum total of NAXJA, they were only an adjunct. I was on the board of directors at a time when there was considerable discussion over whether everything on the site should be equally available to everyone. The opinions were far from unanimous, but the consensus was that it was not at all fair for a relatively small percentage of the people using the site to carry the entire cost of operating the site. That was when someone came up with the idea of putting some of the more in-depth technical stuff in a members-only area. I don't remember if the board vote on that was unanimous, but the proposal passed and was implemented. I think that's what you're complaining about. IMHO, the complaint is invalid. Sure, it's nice to have FREE access to the most extensive technical information available, but somebody has to pay for hosting and administering the site. I don't know how they do it now, but when I was on the board NAXJA not only paid a hosting fee, they also paid someone to do the administration. On this site, Pete pays the hosting fee and Pete handles the admin work out of the kindness of his heart. That's great, and I hope it doesn't change ... but we have no right to expect that someone will always make this great site available to us for free. NAXJA's decision to limit access to some of the technical archives to dues-paying members only was not undertaken to make a "profit." NAXJA is a non-profit organization, and unless things have changed since I was on the board nobody draws a salary (except maybe the web admin). The decision was a conscientious attempt to balance access against cost, and to find a balance that was fair to both the dues-paying members and to the hangers-on.

Nope. The Clayton kit includes a complete new crossmember. The two outer ends, which also incorporate the mounts for the arms, bolt to the unirails at the point where the rear section is nested to the front section, providing a double thickness of steel. In addition to the bolts, the end pieces are welded to the uniframe sections. The center portion of the crossmember is bolted in between, so it's removable for tranny service. He designed it to mount where it does specifically so there would be enough thickness there to weld to. It's VERY strong. There are a LOT of his kits out there, and I've never heard of one breaking or tearing loose from the body.

Not really. All timing does is optimize the amount of power you can get from the gasoline you're burning. The key is that you need the fuel-air mix to ignite at a time when the expanding gases resulting from combustion will be pushing down on the piston after it has passed top-dead-center, and not before. The combustion isn't an instantaneous event, and that's the problem. If the "event" starts too soon, the pressure starts to build before TDC and you lose power because some of the combustion is actually slowing the piston down as it rises toward TDC. In extreme cases, the expanding flame front slams into the piston destructively, with the flame front slamming down and meeting the piston as it's rising up (rather quickly) -- that's what we call "detonation," or "ping." Ping IS a destructive event, which is why we don't want to hear it -- ever. On the other hand, if the combustion "event" starts too late, the piston will have gone beyond TDC and started down again, leaving a larger combustion chamber and resulting in lower compression. Some of the energy produced by the "event" will thus be lost -- or at least used less efficiently. Now ... what most folks don't understand is that ALL gasoline contains the same amount of energy per unit of volume. Octane doesn't add any energy or power to the gasoline. All octane does is slow down the rate at which the fuel-air mix burns. What that accomplishes is that it slows or reduces that advancing flame front, allowing the timing to be advanced farther before TDC so that the event can begin earlier, with the goal being that when the piston reaches TDC the combustion event will be reaching maximum expansion, thus generating maximum power. Going back to my old 199 c.i.d. Rambler American, I don;t remember the "official" timing spec, but I think it was around 4 degrees. And it was for regular gasoline. By switching to high-test, I was able to take advantage of the delay in the flame front and dial in quite a bit more advance than what the actory called for. The dealer who sold me that car was a family friend. My grandfather began buying cars from his father before WW2. I mentioned to him one day what I had done and what kind of gas mileage I was getting. He nearly had a heart attack. "Geez," he said, "don't let anybody hear you say that. My God, if anyone hears that ALL my customers will be coming in and asking why they don't get 28 miles per gallon." So ... more timing might mean more power -- if the gasoline is properly matched to the timing spec. Too much timing advance with a low octane gasoline, though, will blow the tops out of the pistons in a VERY short time.

See other thread ... Your gearing should be 3.07 if 5-speed, 3.55 if automatic.

What book says to resurface the flywheel? I know the Jeep FSM specifically says not to resurface. To quote: "Minor scratches, burrs or glazing on the flywheel surface can be reduced with 180 grit emery cloth. However, the flywheel should be replaced if the disc contact surface is severely scored, heat checked, cracked, or obviously worn. Flywheel machining is not recommended. The flywheel surface is manufactured with a unique contour that would be negated by machining. ..."

2 to 8 degrees is too low. The FSM and all the aftermarket manuals agree that timing is not adjustable on the 4.0L so they don't provide timing specs. But -- the 2.5L began life with adjustable timing and then it became non-adjustable when it went to the same Renix-based ignition as the 4.0L. The initial timing listed for the older 2.5L engines is 12 degrees. Then we should keep in mind that the 4.0L is essentially the same engine as the older AMC 199/232/258 6-cylinder engines. For the 258, 1983 is the last year I have tune-up data for. The timing for that year is given in Haynes as 15 degrees -- and 19 degrees for the high-altitude models. Initial advance was less way back in the 60s, but I remember that I used to run my 199 c.i.d. I-6 at 12 degrees, which was more than called for but I ran high-test gas to eliminate the knock problem. I also got 28 MPG highway, which was the purpose of jacking the timing beyond factory spec. With the Renix 4.0L, the initial advance can be pushed way up because the system has a knock sensor, and what that does is retard the spark when it sense detonation. In fact, the Renix system has a high-altitude CPS available, and that version of the CPS provides more initial advance than the "flatland" version. I've been running a high-altitude CPS in my '88 XJ for years. My house sits at elevation 475 feet above sea level, and I have no problems with detonation.

Dealer

It isn't just the quality of the welds that's a concern. Clayton is, by training and profession, an industrial engineer. His kit wasn't thrown together. He wheeled a ZJ (which is what the kit was first developed for) and he looked hard at what he broke each time he was out. Then he engineered a long arm kit that was optimized to be more than beefy enough where things get stressed, without being made of cast iron and weighing three tons. He also had the knowledge to evaluate what was needed in the way of purchased components, such as rod ends (I think he used Johnny joints, but I don't recall). That's why I stressed design and engineering. If you don't understand how this stuff works, you can make up a finely crafted pile of hardware that'll kill you in a heartbeat. Keep in mind, too, that materials have a cost. You asked for "cheap." If you as an individual were to set out to build your own clone of a Clayton kit -- I seriously doubt you could produce just one for less than what he sells his for.

Someone else encountered the same problem when doing a cluster swap, if I recall correctly. Wasn't me. Try searching -- or maybe whoever it was will see this thread and jump in. It's not a bad bulb. Bad bulbs don't light up.

It was external in 1986 (and 84 & 85 in the XJ). It went internal in, I believe, 1987 (maybe 1988), and then went back to external in 1994.

I understand that money doesn't grow on trees and that you may feel you can't afford an "expensive" professional long arm kit. I know I can't. But I've seen a number of home-made long arm kits, as well as being in Clayton's shop watching how his stuff is fabricated, and being on the scene while he was installing a kit for one of my friends in NAXJA. I gotta tell you, the home-made stuff was so scary that I didn't want to be within ten miles of it -- literally. A poorly designed or poorly engineered or poorly fabricated/installed suspension won't just leave you stuck -- it can kill you. You do NOT fool around with that stuff. If you can't afford to do it right, stay with a 3" lift and 31-inch tires until you CAN afford to do it right. I know this will sound melodramatic, but considering what I've seen -- it's not: How much is your life worth?