I have a 99 jeep xj with the inline 6 4.0 It has 190xxx on it. Should I leave it as it is, replace it, or rebuild it? Im kinda on a tight budget. Ideas opinions suggestions information would really be nice. please and thank you.

 

What's wrong with it?

 

Nothings wrong with it. It just has those miles and it doesn't sound like it has the power it should.

 

Uh, it's a 15 year old engine. Not gonna have the power it left the factory with. If nothing is wrong with it don't bother worrying about it... 190k is nothing for a 4.0... just take care of it and run it for as long as you can.

 

I was gonna leave it that way but wanted other peoples opinions. I'm lifting it now and wasn't sure if for mudding or anything a rebuild or new engine would be best? It is a DD

 

My 94 has 195k on it, no problem. Just drive it.

 

Well... obviously rebuilding would be cheaper... but there is no reason to do it. The only reason you would buy a new engine, AFAIK, would be if yours was too badly scarred to be resurfaced. Could be wrong.

 

So just leave it? Cool. What would be some ways to get the power back? Or increase power?

 

injectors, a real CAI, TB spacer/bored TB, stroker... gearing...

Spark plugs/wires.

These things aren't beasts stock, but they're not horrible... Mine is like a 7-8 second 0-60...

 

Whats stroke gearing?

 

Stroking is (very basically) increasing the displacement via resurfacing in order to get more power.

Gearing is changing the ring and pinion in your axles, which doesn't really increase power but changes how power from the engine is transferred to the wheels.

People don't typically re-gear unless they're running larger tires.

 

So how would you do a stroke?

 

A stroke yo u would be usually doing a total rbuild and machining you woul dincrease the throw on the crank shaft to inscrease yoyr stroke hence stroker and usually you bore out the cylienders some more. If you want to increase your compression ratio you woul dtake the head and block to a machine shop and have them do whats called decking and thats machine a few thousandths off of the head mating surface to make the space between the piston at tdc or top dead center and the valves smaller that area between the two is called a combustion chamber the smaller that is the higher the ratio is the more power you should get hypotheticlly. You can acheive this by putting domed pistons in. Or if you want to lower the compression ratio you can put on dished pistons so you can run a forced induction set up thats all the indepth ways of doing it

 

Okay that makes sense

 

Kinda long but as long as it makes sense. Your best bet is search here and find the upgrades you want to do like bored throttle body and injector swaps intakes and exhausts and then fix or repair anything else and full tune up that will be your cheapest and quickest power gains