4.2ish WJ mini stroker

[savagef82]

I hope your 4.2 stroker is still running strong.

Did you ever diagnose the clunk that developed?

[jeepxj3]

What are the numbers for the 232 crank?
Thanks.

[Knoxes]

Checking back in... the clunk's still there. I'm not sure but I feel like it's a motor or transmission mount torqueing when I hit the starter. It's not any worse than when I first noticed it. And I haven't had time to really investigate it. Regardless, it now has about 2500 miles and is running fine. It doesn't have much, if any more power than it had, but I haven't hooked the tuner up to it either. And it's still running stock TB and exhaust. Fuel economy is reading in the high teens, low 20's on the freeway, but I think those tires that I swapped out off the other GC are undersized and reading fast.

xj- not sure what you mean by the numbers? Stroke? Casting number?

[savagef82]

That's kind of a bummer to hear that you aren't noticing any more power.

I'm organizing the work area in my garage tomorrow to start the teardown and buildup of my 4.2 stroker project.

I'm hoping I notice something in terms of power gains.

[Knoxes]

I put the Superchips tuner on it, and I'm still not noticing much in the way of power gains. There's some, but it isn't anywhere near as powerful as my 4.7L HO in the other WJ. Also, the overhead mpg reading was waaay off. Actual mpg is around 17.5 with mixed driving.

Savage - if you're looking for anything more than getting back to stock power, I'd definitely target the 4.6. A better cam might provide some excitement from the 4.2, but that creates other issues. If I had this to do over, I'd do a 4.6.

[Defcon92]

I put the Superchips tuner on it, and I'm still not noticing much in the way of power gains. There's some, but it isn't anywhere near as powerful as my 4.7L HO in the other WJ. Also, the overhead mpg reading was waaay off. Actual mpg is around 17.5 with mixed driving.

Savage - if you're looking for anything more than getting back to stock power, I'd definitely target the 4.6. A better cam might provide some excitement from the 4.2, but that creates other issues. If I had this to do over, I'd do a 4.6.

From what I can see the motor is basically a stock .060. Of course it does have the 232 crank giving you a zero deck, better quench & slightly more compression. Basically a more efficient stock 4.0. It's probably gained 20-30 hp & 30-40ftlbs but it's also more efficient than a stk 4.0 so should see more mileage & be just as reliable.

I think a lot of power would be held in the head, cam & bolt ons of the motor itself. I'll be dynoing my 4.2. I dynoed stock and will with my stroker to see the differences I've gained. Hopefully it'll get better mileage than stock to.

[Knoxes]

Just cleared 5k miles. I rarely drive it, but it will be getting a lot more action as my other WJ with the 4.7 HO just blew a head gasket. The stroker has a rough idle in gear. Not sure what that's about but I need to get that addressed as it's become a primary vehicle again.

[Knoxes]

After a quick search, it looks like a lot of the rough idle problems stem from running rich. I'm wondering if the combination of the new injectors and the Superchips on this very mild stroker is just pumping too much fuel into the system. I'm going to start by flashing back to stock with the Superchips and see if that resolves the problem. It's not like it's doing any good anyway.

[Defcon92]

After a quick search, it looks like a lot of the rough idle problems stem from running rich. I'm wondering if the combination of the new injectors and the Superchips on this very mild stroker is just pumping too much fuel into the system. I'm going to start by flashing back to stock with the Superchips and see if that resolves the problem. It's not like it's doing any good anyway.

Eager to know. My 4.2 has yet to fire as I put it off for summer. But I'm back into within the next few days. I've got some pretty serious head work, bolt ons & a cam with a .060 over on mine. I wanted stock 4.0 reliability with more power & mileage. Bigger concerns were piston speed & rod angle ect. The 4.0 seems to fall perfect into both those suggested safe ranges for both as does the 4.2l mini setup.

Curious what you'll be getting from mileage on this sucker. If it's worse or better than your stock 4.0. I'd imagine better since your quench should be no more than .055 at worst vs the stock .0725. Should be much more efficient.

[Knoxes]

I flashed back to stock and I think it's idling better, but I don't often drive it (Mrs K's daily driver). Fuel economy as tested is about 18 mpg - probably slightly better than prior to the build.

[SilverXJ]

After a quick search, it looks like a lot of the rough idle problems stem from running rich.

What injectors are you running and what is your AFR at idle?

[Knoxes]

I've looked all over for the invoice (hard copy or emailed) for the injectors and can't find it. I think they were 24lb blue tipped Ford injectors, but I can't remember for certain. No idea what my AFR is - wonder if the Superchips tuner can provide that info....

Found this thread from last year:

http://www.jeepstrokers.com/forum/viewt ... 151#p37151

Seems like I went with the Delphi's from Motor Man.

[Knoxes]

I've been driving it quite a bit lately and overall I'm pleased. It still has that thunk, but only when it's cold outside and the engine is cold.

Also, I'm pretty sure that it's not really the engine idling rough. I think it has something to do with the torque converter or transmission at idle. Once it hits 8-900 rpms, it performs just fine - smooth acceleration, decently solid shifts, etc. And in park, there aren't any vibrations at all.

[Knoxes]

Almost 20K miles. Lik K is driving it daily now. I drove it last night for the first time in probably 3 month and was reminded about how nice that WJ was - comfortable and quiet. It doesn't have enough power, and something went wrong pulling a trailer last spring (billowing smoke), but it's a great platform for a 17 year old boy.

[Knoxes]

Over 30K miles now and Lil is daily driving it. I drove it up to the NC mountains a couple of weeks ago. The WJ platform is such a nice vehicle. I'm still just in awe of it. I've since bought a WK2 with a hemi, which is incredible, but the WJ is still a fantastic car. No issues with the motor. There might be a bit of a rear main seal leak, but it's minor. Just doing regular routine maintenance on it these days. Lil did try to drive under the beach house with a bike and a kayak attached to the roof rack. End result was a destroyed bike, rack and a couple of dings and dents in the top of the tailgate. But we're here to talk about the motor, right....