Eagle

Huh? The block casting number will never match the cylinder head casting number. Head casting numbers are 4-digits, blocks are eight digits. Or do you mean make sure they translate to the same year range? Sorry. I meant match for year of manufacture, not that they would be the same number.

I think you indexed the distributor wrong. Spark timing should be set to fire before top dead center. Since the distributor on the 4.0L is not adjustable I don't even know if the timing spec is published, but with the engine at TDC (on the compression stroke) the blade on the rotor should be at or past the turret on the cap.

Swapped in. Find the casting number for the head -- see if it matches the block.

Actually, it went more by time than miles, but 82,500 was when you were supposed to replace the O2 sensor. Reason this sticks with me is the light didn't come on at the same time as a major, or any for that matter, service. Customers would be pissed. And, since the timer was nothing but a timer -- it wasn't a sensor nor was it able to read actual elapsed mileage -- the 82,500 miles was only a vague approximation. The timer sat there, ticking away at a constant rate, whether the engine was idling in traffic, bumbling along at 30 MPH on city streets, or zipping down the highway at 75 MPH. In reality, the O2 sensor might have gone bad long before the light came on, or the light might have come on when the O2 sensor still had a lot of miles left in it. It was one of the dumbest ideas the Jeep engineers ever came up with. Even dumber, the light module wasn't designed to be serviceable -- in addition to replacing the O2 sensor, you were also supposed to replace the timer module. Since then people have figured out how to reset it, and you can find instructions on the Internet, but resetting it was never supported by the factory.

Here's the engine ID info from the 1990 (Renix) Factory Service Manual. This is really the only way to determine when a particular engine was built. The number you posted appears to be the engine build code, NOT the block casting number. Based on that, it appears that you have "decoded" the date correctly, and what you have is indeed an older, Renix engine (or at least block) in an HO vehicle.

Don't misunderstand my point: The Dana Trac-Lok is a clutch-type limited slip differential. While it's the least expensive such unit on the market, it's also what the factory used. I have Trac-Loks in three XJs and one MJ and I have no problems with it for my use. For a street-driven truck, it's a good choice. That said, in generic terms it IS a "posi." Once you go beyond generic descriptions, "posi" is short for "positraction," which is a GM trade name. There has never been a positraction differential for the Jeep Dana 35 axle. I'm all in favor of supporting local businesses -- right up to the point where they show me they don't know what they're talking about. Once they start blowing smoke I'm gone. Non-Jeep related, a couple of years ago I needed some regrading and drainage work done in my yard. I brought in a local site and grading contractor. Small company, owner lives in town, good reputation. He came to the house, we stood in the driveway and I showed him exactly what the problem was and explained what I wanted done. I specified that the new material was to be 3/8" trap rock (broken stone). A few days later I came home to find the work finished. It was ALL wrong. Rather than remove material to grade away from the house (which was what I had asked for), he built the grade up near the house -- thereby creating a building code violation. He didn't use 3/8" broken stone, he used "processed gravel" -- which is a mix of ungraded broken stone and stone dust. And his processed gravel had organics ("weeds") in it, because within two weeks after he was done I had grass and weeds growing in my driveway. And -- what he did failed to alleviate the flooding. I had to have another contractor come in the following year to make other corrections in order to offset what the first guy did. Being a neighbor in no way equals knowing what you're doing.

I apologize up front, but I am already concerned about this shop. They quoted $1,300 with a limited slip. I assume that's a Dana Trac-Lok, which is what the factory used. It's about the least expensive limited slip you can get. But what's this about another $200 for "posi"? "Positraction" was a trade name used by General Motors for their limited slip differentials back in the 1960s. It has come to be used as a generic name for a limited slip, much like "kleenex" has become synonymous with facial tissue, but when you try to distinguish between a Dana Trac-Lok and something else -- there ain't no "Positraction" that I'm aware of for the Dana 35 axle, and never has been. Did they ever give you a satisfactory explanation of what's wrong with your diff? Did they tell you exactly what limited slip differential they're putting in?

Here's an image of the Custom 4x4 tow hook bracket set. It's pretty much a carbon copy of the factory kit. What's not shown here is the factory bumper brackets, which are used with this kit. Which part are you asking about? The following link will show you how it all goes together: http://jeephorizons.com/tech/xj_hook.html

I suspect the oxygen sensor. The clue that jumps out at me is that the backfire occurs after you've had your foot down, and then let off the accelerator. The ECU is supposed to "see" that and reduce the fuel flow to the injectors accordingly, based on the change in oxygen ratio in the exhaust, as reported by the oxygen sensor. When O2 sensors start to get weak, the response time tends to lag. So if you have your foot down (running rich for power) and suddenly let off, the O2 sensor doesn't report the change instantly, so the injectors keep dumping gas into the cylinders. The engine can't burn it all, so some of it goes right out the exhaust. ==> Backfire.

There's a lot to be said for making up your own parts for armor. In addition to the grinder and drill, toss in a Harbor Freight flux-core wire welder. Costs just over $100 and frees you up to do a lot. http://www.harborfreight.com/90-amp-ac-120-volt-flux-cored-welder-61849.html Flux core isn't going to give you the best welds in the world. With practice, it's good enough for a lot of general purpose welding. For critical parts, you use the cheap wire welder to tack your creation together, then take it to a professional and have him lay down the final welds.

10-4! That's a VERY neat job.

One final thought -- check your state's laws regarding lifted vehicles. You may create your "dream" wheelin' machine, only to find that it's not legal to drive on the street. And before you can even say, "But they don't enforce those laws," -- well, yes, they do. They don't always enforce them, but I got nailed just for having 31" tires that stuck out of the sheet metal too far. If your truck is going to be primarily a daily driver and see a trail maybe three or four weekends out of the year -- build it as a daily driver, and pick trails that are within the truck's capability.

Where's the diagram for the C101?

So you have no idea what it is or what might be involved in making it fit your truck. Not all Dana 44s were created equal. Some of the early ones had small axle shafts and puny spline counts. They also had two-piece axles (the actual hub was a separate piece that was splined into the axle and held with a large nut). They were very prone to failure. I wheeled my '88 MJ on 31s with a Dana 35 for several years. Get your feet wet before you start throwing money at things you don't yet understand. As Incommando wrote, be honest about how you're going to really use this truck. Even on 31s an MJ is a very capable wheeler. Your goal should be to go for the LEAST amount of lift you need and the SMALLEST tires you'll need to run the trails you plan to see. Anything beyond that is wasted money. The rule of thumb is that the price of lifting increases exponentially -- that is, twice the lift, four times the cost. Don't get caught up in that cycle if you don't need to. Your budget of $1.5k isn't even close to enough for what you think you want. Have you priced 35" tires and 15x12 wheels? have you priced long arm front suspension kits? Have you priced custom drive shafts?

BURN THE HERETIC!

Somebody very recently posted a link to the 1988 electrical manual on-line.

What "size" WMS you need for yours? Do you even know what "WMS" means? Because if you don't even understand the terms you're asking about, you aren't nearly ready to undertake a job such as you're contemplating. It's not a simple, bolt-in "swap." The rear might be -- IF you get lucky and find a Dana 44 from a Comanche. A Dana 44 front was never offered in the Comanche, so changing to a D44 there means a whole bunch of custom fabrication.

http://www.eastwood.com/rustproofing-and-undercoating-system.html

NEAT!

Rube Goldberg, reporting for duty SUH! So you need a switch that's normally open, and you have a switch that's normally closed. Splice a relay into the circuit between the switch and the lights. Wire the relay so it's open when the signal circuit has power, and closes when the signal circuit is interruped.

Slapping an "upgraded" bolt in the hole, secured by a loose nut, is not an "upgrade." With a weld nut in the frame, all load on the bolt is transferred into the nut, from which the welds distribute it more or less uniformly over a large-ish (relatively) area of the frame. If all you have is a bolt and a loose nut, forces from the bolt are transferred directly to the frame at the point where the bolt shank contacts the hole. Less than half the circumference is actually positioned to resist forces in any particular direction, so it probably won't take long for the hole to become elongated. Once that process starts, how do you stop it? Of course, if the weld nuts bust loose in trying to remove the bolts, you have no choice. But I certainly wouldn't recommend intentionally breaking them loose. The factory bolts for the rear bumper are a lot longer than they need to be. 25mm should be plenty long enough, and 20mm would probably do the job nicely.

True. It used to blow the Ford and Chevy guys' minds when they found that AMC was able to build a 401 in the same block that started out as a 290.

CJLongshot has a section in his build discussion on plating rust in the frame. That's the right way to do it -- unless there's not enough left to plate to. Photos -- we need photos.

Start here. http://comancheclub.com/topic/46497-triangle-gaskets-inside-valve-cover/ Links are your friends

Urethane will ride HARD. They also squeak.