I bought a 2001 Cherokee Sport 4.0 with high mileage and a tick I believe in #1 or #2. I have had the motor tore down and replaced the lifters and still ticks. I have torn down again and inspected rod bearings wrist pins and rings and all are OK. I have pulled injector wires and makes no change. It is really bad on cold start up then gets better. If it is warm and sits for about 5 minutes and restarted in barely ticks at all. I am thinking piston slap, but how do I pinpoint which cylinder? If it is slap will it go away with new rings or will I need to replace piston? I have read alot of forums on this and am hoping for some advice.
Re: 4.0 tick
Next time you tear it down, check the pistons with a good caliper. And plastigage everything you can.
Slap is rarely rings, but I wouldn't pull any pistons without just re-ringing them
all as a matter of course.
Unless you are doing all this work yourself, you can find stroker 4.5s and 4.7s pretty cheap unless the rest of the drive train is also weak. Even if you are doing it yourself, a stroker crank is an instant torque/power boost.
Istowell is dead on.
If you tear it down again get a 4.2 snub nose crank and 4.2 rods. That will give you 4.5 liters and instant torque and HP. Your MPG will actually be better like 1/2 to 1 MPG. You can swap you cam with the 97 xj cam its better on exhaust lobes.
I build these a lot here in Daytona beach.
Edit: you may probably have the 0331 head. I would suggest swapping that out with an older better head. Those 0331's crack very easily. That may even be part of the ticking.
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