Since the internet has been a great resource for most of the information I needed for this project, I figured I'd offer my experience to those out there like me, that decide to take on these crazy projects!!
I'm going to break this up a bit as it'll make it easier to read, and I have a lot of pictures. For those just looking for information/tutorials, or those not wanting to read my rambling, you can skip to the next post.
This is going to be an on-going post, because as you will see shortly, the re-build went from bad to worse, and I'm now on my second round...
(If you prefer, you can just skip Here to see the final result)
A little background:
I bought my 2003 WJ Limited 4.7L non-H.O. in 2008. Right from the start it had its share of problems. The battery died and wouldn't restart on the test drive (perhaps this was an omen!). Shortly after bringing it home, one morning it fired and immediately started running rough, and threw the check engine light. Turns out the left bank had thrown a cam follower. Over the next few weeks I would battle this issue, having it occur three more times (Link to Previous Post). Finally, after much hair pulling, the dealership rebuilt the left head under warranty.
At the same time, I was having overheating issues, and the dealership also replaced the water pump and thermostat. I began to believe this was all related, and that perhaps the previous owner had severely overheated the rig.
Fast forward a bit, to around 18 months ago. The Jeep started having cooling issues, was losing water, and when it was cold out, would "steam" out the exhaust for a bit. I did all the normal checks, (dye test, pressure test, compression test, etc) and had a trusted mechanic do the same. Verdict was, "somewhere" I had a small leak in the engine compartment, causing the water loss, and the intake is sucking in some water through the CAI filter causing the brief steam. I poured in a can of stop leak, hoping that A) the leak would get worse and allow me to actually locate it, or B) stop for the time being.
About a month ago, I decided to finally figure out what the issue was, as it's been nagging at me for quite some time. I performed a pressure test and a block test (exhaust gas test). I found I had a leak in the heater return hose, and exhaust gases in the coolant... This meant it was time for some drastic engine overhaul...
For those who don't know, Autozone will "rent" tools. The way it works is you buy the tool at full price, but you get a 90 day no questions asked return policy. I actually returned the test fluid bottle, empty and received a full refund! The ring compressor I rented broke on the last piston, and I also received a full refund (didn't expect that).
So for the block test, I obviously rented the kit from AutoZone. It comes with a "test tube", suction bulb, and test fluid. The way it works is you pour a small amount of fluid into the tube, start the vehicle (it must be cold!) with the radiator cap off, and insert the rubber stopper into the radiator opening. The rubber bulb sucks the "air" out of your radiator and checks it for the presence of CO. BE SURE NOT TO SUCK IN ANTI-FREEZE, as that will ruin the test fluid and you have to start over.
Here is a picture of the fluid before the test.
If the test is positive, the fluid will change color and look like this.
That means that there are exhaust gases present in your coolant system. This is usually the sign of a blown head gasket, or cracked head. In my case, it was the latter.
Last edited by 65Mustangs; 04-26-2012 at 01:21 PM..
Reason: Fixed images
I decided to rebuild the motor on my own, trying to save a few bucks, and thinking it was something simple like a blown head gasket...
I attempted to remove the heads with the motor still in the rig. This was an idea I quickly abandoned... Though it's possible, you WILL bust a few knuckles, bleed, and swear. A LOT. The "easiest" way is to pull the motor, then disassemble.
In order to do this, the entire front of the Jeep must be removed...
To get to this point, it's taken me and a friend about 3 days work. The NUMBER 1 tip I can recommend, as you disassemble, use ziplock bags to organize and label your bolts for each component / step of the process!
Even with doing this, I still had trouble locating everything when it came time to reassemble...
Also, take your time. There are more wires, connections, bolted on ground wires, than one can imagine. If you miss a single one, it'll cause a headache trying to figure out what the motor is caught on, or worst case, you damage / destroy wiring, sensors, etc. costing you more time and $$$
It's been a few days since I've posted, as I've been busy working on the Jeep. I'll continue with where I left off...
So after removing the front of the rig, disconnecting all the misc wires, grounds, hoses, etc. The motor is ready for removal.
A word of advice:
When I pulled the motor, I left the torque converter connected to the flex-plate. The FSM says to remove the torque converter bolts, and leave it attached to the trans. This is a difficult feat. Instead - remove the trans and motor together as one unit, then uncouple when you have it on the ground. Also, reassemble this way, as it will keep you from damaging the input shaft on your trans. Something I found out the hard way...
With the motor removed, I was able to unbolt the heads and discover my problem... (that's antifreeze in the #4 cylinder...)
After finding the problem, and breaking the motor open, I discovered that the water had started to "pit" the #4 and #6 cylinders. I decided to have the block machined 0.020" over to give me a fresh start.
The first step is removing the pistons from the block. To do this, the oil pan and lower girdle need to be removed. The connecting rods unbolt from the crankshaft. The rods on the 4.7L are a "split rod" or "cracked rod" meaning that the cap and rod are not machined, but cast as one piece and then broke apart. It may be a little shocking the first time you see this, but don't worry, it's supposed to look like that.
I purchased an entire rebuild kit from AirRam (http://www.airram.com/). Nick has been an awesome resource and much help.
The kit came with all the necessary bearings, seals, new pistons, rings, etc. I also ordered new head bolts, connecting rod bolts, and girdle bolts. The connecting rod bolts and girdle bolts are torque to yield design, so they MUST be replaced when doing a complete rebuild.
I had the machining done by Paolo Engine Service in Oregon City, OR. (http://www.paoloengine.com/). The bore was opened 0.020" the deck checked for flatness, and the whole mess was hot tanked to clean it throughly.
The next step was to press out the wrist pins, remove the old (smaller) pistons, and install the new pistons and wrist pins. I tried to heat shrink the wrist pins in, but it's a difficult process to do on your own at home. Luckily I have access to a hydraulic press at work, and I was able to finish the job there. If you are doing your own rebuild, I suggest you bring everything to your local machine shop and have them do it. I was quoted between $80 - $120.
Make sure that when you assemble (or have assembled) the pistons to connecting rods, you have everything facing the proper direction. The pistons I bought had an "F" cast onto the forward side, as well as an arrow marked on the piston face, to indicate which direction the piston was installed. The Connecting rod has an "oil slinger slot" which should also face the front of the motor.
For those who are observant, you will notice that the last picture, the connecting rod is installed backward. I screwed up on the very first one...
Once you have the wrist pins and connecting rods installed, it's time to fit the rings. Unfortunately I didn't get any pictures when I did it, but I bought a ring file to do my sizing. I think it was $40 from Speedway.
To check the size and clearance of the rings, insert the piston without the rings into the cylinder bore. Take your first ring, and insert it into the bore, sitting flush on top of the piston. This will ensure that the ring is sitting perpendicular to the cylinder bore, and will give you the most accurate reading. Use a feeler gage to measure the gap in the ring. The gap is to be set as follows:
Top Compression Ring 0.37 - 0.63 mm (0.0146 - 0.0249 in.)
Second Compression Ring 0.37 - 0.63 mm (0.0146 - 0.0249 in.)
Oil Control (Steel Rails) 0.25 - 0.76 mm (0.0099 - 0.30 in.)
It took me a few hours to size all the rings and install the rings onto the pistons. Take your time as one mistake here can make the difference in your motor burning oil and having weak compression, or making it a sweet, tight running machine!
After sizing all the rings, use a Ring Compressor to install the pistons into the block. I rented one from AutoZone. They are cheap, and you may be tempted to purchase your own, but the one I got from AutoZone failed on the very last piston. I had to use a hose clamp instead. Because I rented the tool, AutoZone took the broke piece back and gave me a full refund!!
Here is a neat link to some videos to walk you through the process. It was actually quite enjoyable to do. I find things like this tedious at times, but I enjoyed assembling the motor on my own.
Oh, and this is my obligatory "Where did you get HO cams??!?11" post.
Haha! yea... about that...
AirRam was out. I was tempted to call the stealership, but found a place online that had them in stock. FactoryChryslerParts.com
There was a little mishap, in that they only sent me one side. I called and talked to them, and they guy was pretty cool. Apologized and had the second cam shipped right away. From what I understand though, AirRam does have some in stock, or at least did a week ago. So if you're looking...