Well, after a lot of troubleshooting I found at least one bad lifter in my 2000 GC 4.0. I haven't checked cam lobes for wear yet but in the event the camshaft has to be replaced, has anybody used a bit of a performance cam before? I dont want to have to get computer work done or anything crazy like that. I know that the factory cams are pretty lame and a cam with just a bit more oomph can make a big difference. chime in, let me know what you think.
I had to replace my camshaft and lifters shortly after buying my WJ as well. I wondered the same as you about installing a more aggressive camshaft but I never really found the information I needed. I'd be curious if there were a camshaft that would be considered an upgrade yet not be too aggressive for a stock 4.0.
Here's my write-up on changing out the camshaft and all the other corresponding parts:
Yes, I read all of your threads regarding your Jeep and it helped me diagnose my issue. Turns out I have the same problem on the came cylinder as you at nearly the same mileage. 88,000 on crate motor. My lifter wasnt worn out like yours was, but mine was collapsing. I pulled the lifter apart to see what went bad inside and the inside of the bottom of the main lifter barrel had a really strange wear pattern to it and the bottom of the spring was just about worn through. Im going to pull the rest of the lifters today and start checking cam lobes to see if a cam replacement is needed.
Im looking at the CompCams X4250H. It says its a great stock replacement but in the notes on the specs page, it says that stock valve springs cannot be used.
I called and talked to CompCams today because I was getting really confused on their listings for the 4.0 on their website. Randy told me that they have a special grind camshaft for the EFI 4.0 but they dont sell enough of them to have them on the website. It doesn't even have a part number. He said that its a great stock replacement requiring no computer work, uses stock valve springs and is a direct replacement. $192.73 for the cam. Its a custom grind which will take 3-4 days to have made and about 2 days shipping he said. I went out on a limb and ordered it. I guess I will be the test dummy!!
Im hoping to have it either Monday or Tuesday, have it up and running no later than Wednesday. When I get it going, ill post my results as well as the cam specs for you all to see. He rattled of some duration and lift numbers and I compared them to a listing I found of the stock cam profile and I think its going to work well. Not too far off from the stock numbers....just how I wanted it.
Once I went by the advice of the guy on the phone with comp cams. I was looking for a cam to put in my 86 chevy pickup that I used for hauling heavy loads. After I got it in, I could hardly get it to take off from a dead stop. The power range was WAY higher in the RPMs than I needed. I was pretty upset and and I let them know it. They exchanged the cam for a really awesome stump puller. Lots of torque.
Wow, I guess I completely forgot to get back here and update with the results. After installation and driving for a week or so, I gave the camshaft a thumbs down. The idle was decent but seemed to hesitate quite heavily when taking off from a stop. Power increase was barely noticeable. It even stalled on me a couple times from a dead stop. Would I do it over again? No.
I think they tried to sell me the same Cam. He gave me a spec sheet. But the cam has no name/PN so it makes it hard to find people using it. Here is the spec sheet. Is anyone else using this cam and what do you think?