Jeep tech questions answered
More Vroom for the 3.8L
I have a ’10 JK Rubicon with the automatic transmission. The only engine modifications are an aftermarket air filter and after-cat exhaust. What would be the best/most power for the buck? What should I do next? It has 31,000 miles on it now.
Unfortunately, you and countless other JK owners are all in the same predicament. The 3.8L is a bit of a turd—there is not much you can do to improve power other than what you have. Anything beyond adding an air intake kit, an aftermarket tuner, and a better-flowing aftermarket exhaust becomes very expensive and will probably just shorten the life of your JK’s engine. By that I mean there are superchargers and turbos for the 3.8L, but many users of such devices report that the minivan engine is not strong enough to be force-fed more air. The only other thing I would make sure of is that your Jeep is geared properly for the size tires that you are running.
I remember reading in an article in Jp where someone recommended a specific brand kit for bending and flaring brake lines. I’m sorry that I can’t remember if it was Christian, Pete, or Verne who made the recommendation, so I’m hoping that you might be able to refresh my memory. Even if you can’t remember the article I’m referencing, I’d still appreciate any suggestions.
I’ve already searched the Jp website and didn’t find what I was looking for. An Internet search steers me toward the $300 Mastercool pneumatic flaring kit. I’m OK with spending the money if that’s the kit to have, but it doesn’t include tools for bending lines. I seem to remember that one of the reasons the Jp staffer liked the kit they recommended was because it was a complete kit and included dies for both American and metric flares, as well as a tools for bending. I know I can buy a bender separately, but I am hoping to get a complete kit so I can keep everything organized and bring it with me on wheeling trips.
I appreciate any guidance that you or any of your guys can offer. Thanks!
None of us remembers a combination bender and double flare tool that does both metric and standard lines. However, I am happy to tell you about my experience with double flare tools and brake line tubing benders. The double flare tool (A) I use is one I borrowed from the local parts store and never returned. It’s alright I paid for it, and if I had returned it they would have refunded my money, but I didn’t ever return it. It was new and in great shape when I rented it, so it joined the ol’ Simons tool collection. Anyway, it’s nothing fancy, but it works. The key in my experience for using a double flare tool is to have a truly straight cut on the tubing. The best way to ensure this is with a mini tubing cutter (B). If you cut the tubing with something else, chances are the cut won’t be truly perpendicular to the long axis of the tube and that is what will make using the double flare tool difficult. It results in a crappy double flare and seal. The other key is to follow the instructions with the tool—make sure you clamp the tubing into the tool tightly and with the correct amount of tube stick out. To make sure the clamp is tight, I tighten the wing nut close to the tubing first and then really tighten the wing nut at the back of the clamp.
One last tip if you ever find yourself flaring really hard tube such as stainless or factory brake lines. To do this use the larger clamp from a single flare tool available from your local hardware store. These clamps are wider and have more threads to grab and hold the tube.
As for tubing benders, I have used several, but I have bent so much brake line that I usually end up just using my hands—but I have ruined my fair share of tubing doing it, too. The best tools (in my opinion) are the ones that function like a large tubing bender but are smaller, with different sized mandrels and a lever that forces the tube over the mandrel (pictured C). Another must-have in my opinion is a pair of brake line tubing pliers (D). These are great if you ever need to tweak a bend near the end of the brake line or when you just can’t get the necessary leverage or other tool on the line. Just be sure to avoid crimping or collapsing the tube, regardless of how you bend.
Hopefully you can help me. Recently I purchased a beautiful silver ’02 Jeep Grand Cherokee Laredo 4x4 with 150,000 miles on the odometer. The 4.0L straight-six engine has a tapping noise coming from the engine. My local mechanic can’t tell me the cause with any certainty. He did an oil change and filter using 0W-30 Amsoil synthetic. After another 700 miles, the tapping continues. The local Jeep dealership diagnosed it for $89 and said it was a bad hydraulic lifter and/or a bad cam lobe. It would cost $1,800.00 to fix. Many of my Jeep club buddies tell me to continue to drive it for another 20,000 miles and see what happens. My choices seem to be to sell it, drive it to destruction, pay the dealership $1,800 and hope the noise goes away, or install a salvage yard or remanufactured engine. I’m confused. What do you think I should do?
Jim, let me start by telling you and everyone out there in Jp reader land that the 4.0L engine is many things. As engines go, it’s reliable, pretty efficient, fairly powerful, and without doubt one of the clickty, clackityest engines out there. They make lots of ticking and tapping noises, even when perfectly happy and in good running order. Having said that, you may have a real problem with your 4.0L, and this is one of those situations where diagnosing a noise via email may not work so well. I will say, though, that a warn cam lobe or faulty lifter should be accompanied by a misfire or some backfiring. Luckily for you, you can figure out if there is a real problem in your engine or if you only have talkative valvetrain that is otherwise functioning as expected. Once you have figured out if there is something wrong with your engine, you can contemplate the repair. The simplest way to figure out if you have a bad lifter or cam lobe is to run the Jeep on a diagnostic scanner that can run a power balance test. The dealership may have done this, and asking them should settle that question. If they did not run this test, then it could be that you just have a particularly loud 4.0L. If they or another garage can confirm that your Jeep has a bad valve, I would look for a low-mileage junkyard engine or look into a remanufactured 4.0L. Generally, when maintained correctly and treated right, a 4.0L can last for 200,000-300,000 miles, so the cost may be worth it if you plan on keeping the Jeep.
An alternative is to pull the valve cover and check lift at the rocker arms with a dial indicator to see if any of the cam lobes are out of spec. Also, you could pull the oil pan and look for excessive metal in the oil pickup and do some detective work to see if you can figure out where the metal is coming from, either the cam or a lifter. If no one can confirm that you have a bad lifter or flat cam, I’d run that 4.0L till it dies of something else.
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