Jump to content


  • Content Count

  • Joined

  • Last visited

Everything posted by AZJeff

  1. I just went thru this issue. To avoid spring rubbing, three things have to be set correctly: 1. The axle must be centered under the chassis by adjusting the track bar so that distance from the outside of the wheel to the outer edge of fender flare is equal on both sides. On a lifted MJ/XJ, this will require an adjustable track bar. 2. The axle spring seat must be centered under the spring seat on the chassis. On a lifted vehicle, this usually means extended control arms are needed if the lift is over about 2 inches. 3. The axle spring seat must be PARALLEL to the one on the chassis. This keeps the front spring from bowing in a manner that will cause it to hit the track bar bracket on the chassis. The only way to control this parallelism is with adjustable control arms. (This will also control your caster angle as well.) It sounds like you have tried to control all of the above, but the one variable that seems unknown is if the springs are really intended for an MJ/XJ. If their OD is too large, no amount of adjustment will compensate.
  2. Do you have the wiring diagrams for both an 89 MJ and a 2000 XJ? That’s the first thing I would get before even STARTING the conversion. This is NOT a plug and play upgrade.
  3. Agreed. Try this to confirm: Start the engine, and while it's still stationary, run the throttle up to about 2000 rpm for about 10 seconds, and then idle back down. Then put it in gear and drive away. If the problem is gone (or substantially reduced) it's your fuel line that is filled with percolated fuel due to heat soak. Fixing heat soak requires shielding/insulating the fuel line in the vulnerable areas (near the exhaust)
  4. AZJeff

    How to Reproduce?

    These are VERY good points that I did a less eloquent job of describing. Making this kind of stuff isn't cheap or easy. Look at how much suppliers charge for the fender flares for an XJ/MJ, and the demand for that part is MUCH higher.
  5. AZJeff

    How to Reproduce?

    I am a retired mechanical engineer who worked with LOTS of plastic molded parts in my career, so here are my two cents: Owing to their size, the original parts were probably created by some short of sheet forming compound. This is a plastic sheet resin that is heated, and placed into a mold where it is pressed into shape and then allowed to cool. Sometimes the material has glass or mineral strands added to increase stiffness of the finished product. Making a duplicate of this part would, of course, involve first making a die (mold) that is essentially an inverse image of the part, both inside and out. Of course, the mold has to be "tweaked" so that the softened plastic does not pull too sharply in corners and whatnot, and thus tear, so an exact inverse image is not usually the shape of the final die. Believe it or not, in low volume production, this could actually be made from hardwood, like maple. Once a die is made, then a suitable material must be found. Sheet forming compounds in large sizes and thicknesses can become pretty expensive in low volumes. It might cost a couple of hundred dollars just for a sheet that is 6 feet long and "x" wide. Of course, the compound you choose also needs to be formable in the die you create, as the "stretchiness" of various resins are different. This might mean some trial and errror experimentation might be needed, and you might end up creating several unusable versions before the die is optimized. All of this, of course, would required a facility with a large oven to heat the resin sheet, and a the ability to fixture the mold halves and compress them together once the heated sheet is placed into the mold. Owing to all of this (cost of raw sheet material, cost of die development and fabrication), making a duplicate of the OEM part in low volumes would result in some pretty high piece part costs. This makes creating parts from fiberglass or carbon fiber MUCH more cost-effective. Making the part in fiberglass or carbon fiber would be done similarly to the way boat hulls are fabricated. A wooden mold is still needed, but it's only the inverse of the outside of the part is required, so the mold cost is lower. The actual part is them "laid up" by hand, with sheets of glass or carbon mat soaked in resin, and then applied to the mold (which has been coated in a mold release compound.) This method is tedious from a labor perspective, but does not involve a fancy facility with an oven and mold presses. It also is more fragile, as noted previously. All things considered, unless you are indepenently wealthy, the idea of "tooling up" to make a OEM equivalent to the original "spoiler" is pretty much problematic. Sorry to rain on the parade here.
  6. So where does one get a spring to put into a hose if the old hose did not have one?
  7. I have mixed opinions about those fancy type outboard seals. People who do a lot of driving in deep mud might find those type of outboard axle seals useful. There is, of course a possibility that mud can become trapped between the inner and outer seals if the mud is thin enough in consistency. (The inside of the axle tubes are not particularly smooth, and thus getting a good seal there is problematic) In other words, they may "fix" one issue, and possibly introduce another in its place. If you drive in dust/dirt like I do, the factory plastic seals are just fine, as they keep rocks out of the axle tubes. This is what the factory intended, in that big "chunks" don't get into the tube, yet minor water and dust gets in (and then gets back out). Regardless of the type of seal you choose, it doesn't mean you can submerge your axle housing with great regularity and for any length of time. The inboard seals are designed to keep oil IN, and don't do much to keep water OUT. YMMV.
  8. That's cheap compared to the aftermarket one I bought from Rusty's ($129). The Rusty's part is OK, but certainly not 4X as good as the OEM one.
  9. I have a CSF in my truck, and also used one in my last XJ.
  10. As I said previously, a properly maintained 4.0 does NOT need an expensive, super-whammy Hesco water pump. It WILL provide a bit more flow, but if the vehicle is already overheating, it's NOT becuase of water pump flow, it's because of something else that is more significant. (OEM water pumps either flow or they don't, since the impeller is either corroded away or is not.) DO NOT remove the fan shroud. The fan shroud is NOT just a safety device to protect your fingers. It actually helps channel the air over the propeller blades to improve it's effectiveness. If the fan is rubbing on the shroud, it's because it's broken or installed wrong (or as you say, the motor mounts are bad.)
  11. I got my 18lb cap on Rock Auto. Or you can buy a Mopar. Either way, it’s obvious the Jeep engineers realized the 4.0 was going to run hotter than the average engine, and bumped the cooling system pressure to delay possible coolant boiling issues. The 18 lb is needed in hot climates.
  12. If an MJ is equipped with all the original type parts (OEM or equivalent), and they are all in LIKE NEW condition, there is no reason for a 4.0 to overheat in normal use, even with AC on, and even in places like where I live, Phoenix. Hood vents, dual electric fans, and other suggestions will make a BIT of improvement, but should NOT be needed to meet normal cooling needs. If an MJ/XJ 4.0 is consistently overheating, it is ALWAYS traceable to missing parts (fan or shroud) or worn parts (fan clutch, radiator, thermostat, etc.)
  13. Water pumps are all the same, in terms of performance, except for some of those super expensive, fully machined ones. The only difference between a Mopar and some cheesy AutoZone pump will be in bearing life, NOT in pump flow.
  14. A couple of things to note: 1. the thermostat should have the small vent holes in it to allow the system to "burp" properly on a 4.0 The Mopar brand ones have this, but you can take a quality aftermarket one and drill two 1/16" holes 180 degrees apart just inside the seating surface and create the same effect. (Be sure to orient the thermostat so the holes are at the "6" and "12" o'clock positions when it is installed. 2. the pressure cap for a 4.0 is an EIGHTEEN POUND cap from the factory. Everyone tries to sell you a 16 lb. cap, so beware. 3. The CSF three row (all-metal) radiator is about as good as you can get for the space available. The MJ/XJ cooling systems are sort of marginally designed. When all parts are 'in spec.' the system will cool under even the toughest climates in N. America. But, if one part of the system is not up to snuff, then all bets are off. The system does not tolerate parts that have deteriorated due to poor maintenance.
  15. If you have no lighting at all, you basically have a battery that is not connected to the wiring of the vehicle. I am not as up on the older MJ type wiring, but since they seem to use fuseable links instead of the more modern power distribution block, I am leaning towards what others are saying--one or more fuseable links is blown or disconnected.
  16. It's going to be SUPER low, like under ONE ohm. Any cable that is got enough resistance to prevent even the most basic electrical functions (like a dome light or parking lights) will measure VERY high impedance, in the tens of thousands of ohms.
  17. The reverse flow water pump would actually make the problem worse the faster the engine ran. Engine blockages would have to be caused by some REALLY cruddy coolant, and/or the use of some of that stupid stop-leak crap prior to you flushing it, but you say the coolant looked OK. In other words, anything that blocked the smaller passages in the block would have completely obstructed the heater core, and you did not report you saw any issues when you flushed it. Here in Phoenix, my cooling challenges should be as bad, or worse, than yours in Texas. I run a 3-row all metal radiator in the MJ/XJ 4.0 engines because of that, and other than my guage being somewhat off, my cooling system works as designed. As far as engine temps, what are you using to measure them? The gauges on the instrument panel are not terrribly accurate (mine is off by about 15 degrees). I always confirm temps by using an infrared thermometer and measure the thermostat housing. At this point, I am suggesting you confirm temps before tearing your hair out.
  18. Cruiser, do you have any local folks you would trust? I ask because the nearest shops to me are in the downtown Phoenix area, which is 50+ miles from my home. If I am going to fight city traffic to get a head, I want it to be a good one. With Clearwater, I know they have a good reputation. But, if you know of someone here in AZ, I am open to ideas.
  19. Guys...I KNOW I have a "0331" head, and I KNOW it has a crack. I have cleaned and inspected it. It's got the signature crack in the "correct" spot. So I KNOW I need a new head, and I WANT the "TUPY" type. Clearwater has those, I think. Is that the best choice, or is someone else offer something better/cheaper/closer?
  20. So my MJ has suffered the dreaded “0331” head crack syndrome common to the late XJ 4.0 engines, and I need a new head. Is Clearwater Cylinder Head still a “go-to” place for a replacement head?
  21. Some of the major highways here in AZ have 6 percent grades that run for MILES, punctuated by short flat sections in the middle. There is no way you can keep enough momentum up to climb that grade without downshifting.
  22. The OP talks about having trouble maintaining speed on ground that is not flat and level. Those of us here in AZ often encounter long mountain grades on the highways, and those are a challenge for high speed driving. For example, my MJ has 3.55 gears and 31 inch tires. It's also an automatic, but it cannot hold 65mph on long uphill grades and stay in overdrive. It keeps wanting to kick down. My solution is to drop it out of OD when climbing grades. My XJ with 3:07's did the same thing, so I wonder if the OP is expecting too much from that driveline arrangement. Also, don't forget that, when climing moutain grades, you altitude is going up, and that means your air density is going down, so the engine is starving for oxygen to some degree.
  23. PRO TIP: Don’t let foreign material fall into the intake manifold and then fail to retrieve it before starting the engine. While installing the new intake manifold gasket on the MJ the other day, I decided it would be a good idea to keep stuff from falling into the hole where the throttle body mounts, and so crammed a hunk of old tee-shirt as a “plug” in this hole, and it worked just fine. When I installed the throttle body, I pulled the tee-shirt plug out and bolted up the remaining intake parts. Now came time to start it up. It starts right away, and runs smoothly immediately. I let it warm up, and check for fuel rail leaks, and all seems good to go. Now for a short test drive. I pull out of the garage, and about 400 yards down the street, the engine starts running rough. REAL rough. I nurse the machine home, and shut it off. I look under the hood, and see nothing amiss. No loose hoses, no disconnected wires. I start it back up, and I hear a VERY noticeable whistle coming (like a MAJOR intake manifold vacuum leak), and it seems to be coming from around the area of the throttle body. I pull the throttle body and begin inspection. The gasket on the bottom looks fine, but then I peer into the intake manifold, and see a small amount of cotton rag material off to one side of the opening. That’s odd…. I grab the rag piece, and start pulling. Out comes a HUGE hunk of tee-shirt, about 15 inches long, and about 4 inches wide. Judging by the burns on the one end, it apparently ran all the way down one of the runners of the manifold, and was probably getting beat up and burned by the intake valve. After I removed the piece, I spent a while fishing in the manifold for any other pieces, but nothing came out. I reassembled it all, and started it up. It ran pretty crappy for a few minutes, and then the engine smoothed out. My theory is that the hunk of tee-shirt rag I stuffed into the throttle body hole was actually TWO rags, and when I pulled out the first one, the second one fell down into the manifold and I failed to see it. When the engine was idling, the rag stayed put. Once I started moving down the street, the airflow in the manifold sucked the rag into the intake port for cylinder #2, and it began to choke on that cylinder, creating the rough running. Now before any of you declare me unfit to work on anything more complicated than a door knob, please know that I have been working on cars for almost 55 years. I had done LOTS of intake manifolds, so this wasn’t a venture into uncharted territory. It WAS, however, the first time I ever left a rag in an intake runner!! In the end, it’s pretty funny. Had my error been made on a more modern engine with limited (or no) valve clearance, I would have been tearing the engine apart after that mistake. Thank God the AMC six is too primitive to have problems dealing with a few bits of cotton rag.
  24. Heads up to those who offered suggestions: I put some adjustable arms on my MJ, and set the length and caster to match the recommendations for a 3.5-4" lift. My spring interference issue is gone, and the truck rides quietly. (Or at least as quietly as an MJ can ride.) Thanks to all who commented.
  25. I can start your collection of components. I have a set of fixed length control arms that are good for a 4” lift that I will give you. All you have to do is pay shipping costs. The bushings on the arms are OEM rubber, and either are new or like new
  • Create New...