I use the standard WIX recomended by Orileys auto. Seems fairly short, but pretty big in diameter. "Kind of like a cheese wheel really." ~ Ron White .

 

It is my understanding that fram filters do filter finer particulates out of the oil. That also means that the filter will clog faster. Again problematic, that means the dirtier the filter, oil volume decreases flowing thru your engine.
Look up "inside royal purple oil filter" on utube. That video should help you make a filter decision. Im going full synthetic royal purple after my 100 hours engine breakin, with lets call it earth oil. Yes it is expensive, I'm trying to protect my rebuilt 4.0HO. Google Bob the oil guy. This guy has slot to say about oil , oil lubrication, and oil breakdown. He's edumacated in oil, And every thing to do with oil.
Sorry didnt want to get to far off topic. Just good info for all. Keep those gears lubbed, and your wheels will turn.

 

Errrr, Yeah..... That's why you buy two K&N air filters. One cleaned and ready to put in the vehicle. And one on the vehicle. Yes it is pricy. But it allows you to get going a lot faster.

 

The oil filter that was on it when i bought it was the OE style/length filter. They put one on that was way too small by appearances. So I asked around on the internet, looked in my manual, and went to walmart to visually inspect filter sizes for my Jeep, before going to majestic lube, where they confirmed it and showed me the filter that should've gone in my Jeep. They put it in and topped off my oil for me for free!
I was told by numerous people that Jiffy Lube is known for intentionally putting on smaller filters. I had a 1/2 guart less oil than I should. If that kind of thing doesn't effect my engine then the manual would let me know that i can also just run it a half quart low and that will be just fine... right???
So anyways, that argument aside (and I doubt that the 80+yr.old man that i bought it from would have a reason to put a "longer" oil filter in it) the sound of tractorness was there and very noticeable by everybody that heard it. I will do my own oil changes from now on. I only went there to get my fluids topped off (saving me $80 in fluids just to use half an ounce here and there) AND get lubed. I don't have a lube gun, nor do I know where to lube. I don't have a chiltons guid or anything like that. I know I can use the internet now, but I would've had to buy lube. Make that several lubes, if you count the transfercase and manual trans case fluids. SO... I will be trying the Rotella T5 15-30 mentioned above, with an expensive WIX filter. It sounds very interesting. At 200,369 miles now, I want to do what I can to preserve this old Jeep.

 

of both the correct 4.0L Jiffy Lube and Mopar filters side by side. I'd bet the external cans are virtually identical dimensions wise....internally, who knows, 'til u cut 'em apart.

With regard to a expensive cotton/gauze type oiled air filter, why would u buy 2 of them, and not use 1 for a year and just keep it in a box? Couldn't one just use a inexpensive OE type paper air filter element for a day while the cotton/gauze air filter is drying out from being cleaned? Can't imagine a OE factory type paper air filter element killing a motor, or it's performance, for a day.

 

I still wonder what the jeep experts on this forum think would be the best oil and oil filter situation for my rig, with it's high mileage. I bought Rotella T 15/40 (on sale 13$/gal) but i took it back because it wasn't enough to complete the job and i couldn't afford another gallon jug of oil. They don't seem to sell rotella by the quart, here. One day i will be able to afford something the jeep will like. untill then, what are your opinions on the best of the best to quiet my valve lifters and give me back my lost power??? I'll just aim high and hope the Jeep keeps smiling.

 

Try some Maxlife in the appropriate grade for your climate.