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02 WJ 4.7 Re-Build/Upgrade

20K views 27 replies 10 participants last post by  FlyinRyan 
#1 ·
Ok, this is my first real post here guys and gals but I am asking for the advice of the collective...

I have an '02 GC Limited 4.7L 'N' (non HO as I understand) with a blown engine. I left it in 4WD Low and my wife took it to work...well actually about 3/4 mile down the road at 40mph until parts began shooting through the oil pan and it seized up on her!

So I could drop $2500 for a Used motor and have it installed with no clue as to it's history or pay $2500 for a warrantied rebuilt motor and I do the install. I am doing the latter as the rest of the Jeep is in great shape for 130k miles and paid for.

I figure that if I am gonna have it tore down this far I wanna see if I can add some more power to it. The stock 235HP just never felt like enough to me. Personal taste but hey, why not?

I do not want to wrap thousands of dollars up here or I'd just get a new Jeep altogether. I am thinking an after-market air intake system and possibly pulley system if it's been tried and proven effective. Yes, it's been years since I've pulled a motor but I'll save the $900 labor and do this one so bare with me plz if my lack of experience is too obvious.

I think that's about it. Thanks in advance for any advice!!

Adam
 
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#2 ·
Welcome to the forum, Adam. I too have a '02 4.7 non-HO.

Lets lay down the basics before you start throwing money and parts at your truck:

What's your budget?

Do you plan on daily driving?

What octane gas do you want to run?


If I had access to your wallet, here's what I would do. I'd get a reman motor and before swapping it in, I'd throw in some HO cams (they are on national backorder but you can get a set used if you look hard enough), and some Beehive springs. the HO cams have a more aggressive profile, and make significantly more torque down low. the HOs are also cheaper than the other available grinds out there. They are arguably the best "bang for the buck" profile available to date.

I'd get the 2008+ 4.7 intake manifold, along with the necessary Throttle Body adapters from Nick at AirRam.com . To my knowledge I am the only person to successfully swap this manifold in a 4.7 WJ. I can personally guide you with the install.

Speaking of TB's, a easy way to gain some throttle response is a ported or bored TB. I sell ported TBs, but other vendors that cater to the 4.7 are the Fastman, and F&B sells Billet castings.

Regarding an intake, I'd honestly piece together one using some Aluminum piping. I had a 3" plastic intake and when I swapped to the '08 manifold, I opted for a 4" system I put together. The sound is unlike anything else!

With the above setup, you can run a stock tune, but you'll be at the point where you really should consider a custom tune. SCT is the only company that currently sells custom tuning programmers. I am currently running a stock tune but I have tuned in the past with Sean Powell....he is among the best. I am running the above mods (minus HO cams- I am still running non-HOs) and above 4500 rpms I see AFRs of 13.2-13.5:1. This is , IMO, right on the edge of being safe on a stock tune.

The above mods would cost you approximately 1500 (2000 at most) on top of the long block. You'd be good for roughly 350 crank, on pump gas, and with better than stock drivability. This is a setup your wife could drive ( although I doubt you'd want her to :lol: ) , all the while it'd rip from off-idle to 6000+ rpm.
 
#3 ·
Iwould look at LKQ yards. I got a 08 4.7 gen 2 with 3000 miles for $1100. I would think that the 02-07 non-HO engine would be in the 800-1000 range and they have guarantees. Find a nice low mileage one. www.car-part.com is a good place to start. Then look into what Sleepy above says with some SCT or superchips tuners
 
#4 ·
Wow, great feedback guys! I am budgeting about $4000 for the whole project. The motor (unless I can find one cheaper like Scottina06 suggested) will run me $2500 so I can't go crazy above that but it sound like I may not have to. Last time I worked on a completed tear down and rebuild it was a Carburated (albiet Holley/Edlebrock combo) 80's Camaro. I just don't want the new computer or any main sensors yelling at me cause I tweaked it. Sounds like I won;t have to worry too much tho. I am gonna put a LOT of thought to what Sleepy4.7 said. Helps me really wrap my head around this.

I went from handing it off to someone else to do an old engine swap to figuring :if I'm going this far..."

I love my jeep. My kids know daddy can go anywhere and always be safe in it. It will be a daily driver. I don't mind putting 91 octane in it. I tracked mileage with different octanes for the last year and a half and it really didn't cost much more. It was still only about 12.7 mpg with any fuel but it was an old engine with 130k on it.

I will start the hunt for some HO cams and a '08+ intake and see what kinda deals I run into.

Thanks again!!

Adam
 
#8 ·
Adam,

You're welcome. 4000 is a nice little budget to play with, but it doesn't exactly tell us what that is expected to cover.

Do you already have the tools and hard parts needed to do the physical swap? i.e. cherry picker, etc etc.

You should probably factor in about 500 bucks for new sensors (Cam position, Crank position, O2 sensors) to go along with the new motor. A little preventative maintenance goes a long way, and when is a better time to replace parts than when the engine is out of the bay? My WJ is lifted on heavy 31's (60+ lbs a corner) and I manage to get 16+ mpg mixed driving. I dont know what your driving habits are like, nor where you drive, but I'd imagine that you at minimum could use some new O2 sensors with that kind of gas mileage. I have 125k on mine, but alot of it has been highway driving.

You could probably find a used longblock for cheaper than the 2500 you outlined. I would think, at least. It would not hurt to check ebay, or craigslist. Theres always a risk buying used, but chances are it'd work out OK, and leave money for other items of concern during the swap.

The setup I outlined for you will pass emissions and inspections with flying colors. No codes. I figured you were a family man and you'd want something that was very streetable, just alot stronger. this setup uses actual factory Jeep parts (intake manifold and cams) at the heart and soul of it, with a little custom work engineered to make it work best. :) . I have to emphasize however, that you're going to want some sort of SCT tuning. Even if it's a stock timing map with some extra fuel added to keep things safe at WOT.

Scott made a good suggestion with heads, however I don't think there is room in the budget for that. If you allocate some more money for that, PM me, I will recommend you to a shop that ONLY does porting. They are among the best in the biz, and are very reasonable in their pricing.
 
#5 ·
Sounds like a great project your gonna get yourself into Adam!

Ryan's list is pretty much everything I want to do to mine, so if you follow that you're gonna haul ass bro! Keep us updated on the project as you progress on, oh and welcome to JG!
 
#6 ·
if your gonna have the motor apart to install cams or anything....I would look into some race ported heads too. Get ya 300 hp out of it while your at it
 
#9 ·
I have done anything you could want to do...... heads are pretty damn expensive but a very good mod. Cams are great if you can get a set of HO's. Intake is also a good idea. I have basicaly my entire 4.7HO i just ripped out of my running jeep.
 
#10 ·
I'm a pretty aggressive driver by myself but currier the kids around a lot so Sleepy4.7 is spot on. I do have all the tools I need or can borrow them including the picker. I have a pretty decent setup already, and had to replace most of the sensors over the summer last year; cam, crank, O2's. Mileage did improve some but it had almost 100k on it when I bought it. I am pretty sure it was a repo but in great cosmetic shape. I think I paid $7k for it and it's paid for. Well it was lol! It can only improve from here. Ended up btw replacing the fuel pump on the summer project and a grand later I was back on the road.

That's a bit more about me and my habits I guess. I'll keep progress updated when I get going in here. I am looking at a cpl wks to get started.

Thanks again guys!

Adam
 
#11 ·
Well, The Best Laid Plans and all...

The IRS messed my tax refund up and I am going through the Forever long process of appealing it. What this means is that I have a couple grand to work with and not the 4 or 5 I planned on. Argh!!!

I am needing wheels sooner rather than later so I am back to looking at dropping a used motor in.

I suppose if I am gonna go that route and most of the junkyard motors I've seen leave the peripherals attached I wonder if I could drop an H.O. in instead of my standard 4.7?

Anyone know of any mounting or linkage etc issues that might accompany that? Will the tranny mount up the same?

I hate making such a compromise here. I was very much looking forward to that motor build in my garage but life said No for the moment.

Thanks again for the help of the collective guys!

Adam
 
#13 ·
Ok, this has taken WAY TOO LONG to get moving again on my part but money and lack of parts around here have killed me. The good news is I was able to find and buy an 02 4.7 H.O. with 100k on it. I am wondering if I bought a new PCM on ebay, I did for my old motor and it worked great, if I could have them just program it to recognize the H.O. motor. I have emailed a vendor. Will post response here. I am going to go through the new.old motor because of it's mileage but it should be a great foundation to build upon! $1500 too!! Now...How about Ryan's upgrades on this puppy?
 
#15 ·
The PCM is my only real issue here. The new motor has a 16 tooth tone wheel like the old non-H.O. did so no issue there. My problem I can't seem to wrap my head around is the PCM. I have the VIN of the vehicle my replacement motor came from but they no longer had the PCM. In fact they literally cut the wiring harness and yanked the motor. IF I buy a PCM programmed to the motor VIN thus working properly with the H.O. sensors, I know my ignition keys will not work unless programmed to the same VIN. Not likely to get a dealer to do that. If I keep the stock PCM I have I lose what? I know it's not designed for 2 knock sensors but from what I've read I can use 89 octane or better fuel to make that a non-issue. Any other Real issues you guys have come across? Thanks so much for your help here. I am ready to shop for bearings etc and give this motor a once over and get..it..installed!
 
#18 ·
Google Brian Stroud. There is a JU thread. he swapped a HO motor in and made it work on a NON-HO PCM. I believe I remember him saying that there is provisions in the Non-HO harness for the knock sensors.
 
#20 ·
Thanks Sleepy!

Looks like Brian had some real issues but it looks like he had some year to year differences in addition to the HO - non HO changeover. I will follow him to see how it all works out. I am same year here and gonna try his basic experiment of using my current PCM with the HO motor. I don't wanna have to buy new keys and Try to get someone to program them to engine VIN and not vehicle VIN. Then hope the A/C and other accessories work still. Taking from what you guys have said throughout this I will plan on running 89 or better fuel. Now just waiting on rebuild kit to get here. Will post back when I have some progress. Thanks all!
 
#24 ·
Think it's about time for an update?!? Me too!

It's in. After almost a year of delays due mostly to money it is in. I was afraid to turn the key knowing it would only be the beginning of a painstaking troubleshooting nightmare. Battery charged, key in the ignition...one, two, three seconds later its running perfectly!

I just could not believe it. The brake rotors had rusted terribly and the tires had even lost air but this darn H.O. motor roared to life. That was 2 days ago. I've put 85 miles on it, stopping frequently to check fluids and check for leaks or odd sounds and smells. So far so good. I know I shouldn't have but I gunned it a cpl times and it is greatly more responsive than ever. I have been driving my wife's 2005 Liberty with a V6 which is nice but definately not THIS. I will upload some pics too.

I did fill up on gas before the last motor blew so I added a bottle of octane booster to this tank 2 days before trying to start it. Seemed to work. No knocks. I put a K&N filter with a homemade pipe instead of the stock and opted for a set of Pulstar Iridium plugs which are $20 each almost everywhere but found on Amazon.com of all places for half that.

Will add more later. Sorry for the delay and thanks for all the support. Any advice on replacing the stock exhaust?
 

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#27 ·
All going well so far with only a few bugs popping up. Really only one. The fuel gage went to empty and stays there regardless of how much gas is actually in the tank. I had a new fuel pump installed by the dealership summer 2009 and no problems until the motor blew 6 months later of course. I put my ODB scanner on it and told it to clear all codes. There were none but oddly enough the gage began working again...until I started the engine then same issue. Again I could reset it with it off but no clue what is confusing the computer. Any ideas?

Oh and a FlowMaster Super 44 is way too loud for my little cul-de-sac LOL! Got it for $60 new on eBay so maybe try to go with what others have had success with and not be out too much more.
 
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