When to rebuild a stock 4.0L?

[okieTJ]

I am new to the Jeep Thing and love it so far. I bought a 1997 TJ last year and the first thing I did was put on a 3.5 Rubicon lift and 33" tires. I then replaced the 3.07s with some 4.56 and this thing rocks! I am wondering how long and strong the stock 4.0L will run. It currently has 130k on it and seems to be running good no leaks present. I just replaced the plugs, wires and put on a Fram Boost Intake. Is there anything else I can do-how many more miles should I expect out of this engine? Thanks for the help in advance.

[Davisrats]

I have 3 4.0L , 60,000, 240,000 and 270,000. Going strong

[killwhytey07]

One thing I would recomend with any engine, is put some schaffers, or royal purple oil in it, this stuff is the best you can buy, it has moly somthing or other, which is a dry lube that takes heat like no other, and the mechanic that recomended it to me said you can put it in, run it for 15 minutes, drain it out, run it around town, and the moly will actually protect the motor, now i wouldn't recomend doing that, and maybe this is superstision, but I think the oil really is great.

It's a full synthetic too, so it's rated for 15,000 miles.

[D4x4Fish]

I do a compression test dry/wet on my jeep once a year and record it. If all 6 cly are the same, and oil pressure is good, why do a rebuild.

[1BadWJ2B]

Try and break it...

I have met other jeep lovers who barely have any jeep left and their I-6 still runs like brand new. I have witnessed something like 468K on a 98 Grand....it ran as good as mine at 120K. You would have to do something pretty serious to that engine to need to rebuild it anytime soon.

[YJwonderboy]

Yeah the 4.0L motor is a wonderful motor in terms of wear. They will run forever just about. just like any motor, you've got to keep it maintained, and Killwhytey, it's Molybidenum...I think. Anyway, the 4.0L is a good strong motor, and will stay strong longer than your Jeep will most of the time.

[brokenujoint]

do what im doing

slowly put together a 270 hp 4.6 stroker while you still drive your 4.0 around. some day(sooner than later) it'll be time to throw that tired iron in the trash.. slowly build up a engine. start with the block and head for about 300-400 bucks locally( look for a 96-98 4.0 block and a 91-95 head. )then when youve got those, email me for the rest of the fun things to do and the extensive parts list...