BulldogMJP

I have the timing cover off. There's quite a bit of slack in the chain so Im going to replace it. The jeep has 170000km. Is there any special tools required to remove the chain and sprockets. All I have is a 3 jaw puller that I used to remove the Harmonic Balancer.I see the service manual shows a chrysler tool. Any tips and advice would be greatly appreciated.
Thx

webejeepin

Just curious what caused you to investigate the chain?

Never done one myself but I recall other motors I've seen this done on, both top and bottom gears are "indexed" and should be in alignment prior to chain removal.

Sorry I can't be of more help. I'm sure more experienced folks will chime in here soon.

BulldogMJP

Engine was knocking low end. Traced it to front cover area ,pulled pan and found slack in the chain. Ill put a new oil pump in whilst im at it. I have lined up tdc.
Will post pics when Im done. Stuck on the sprocket removal now. Ill probably sleep on it and go at it again tomorrow. As you can see I managed to get a puller on it. It doesn't want to budge.

webejeepin

Thanks.

Hmm no budge eh. Is there a keyed slot that's causing an issue? Been there with other things I've worked on, good nights rest, fresh start in the AM with a coffee is usually all you need. Maybe some PB blaster and a love tap from a ball peen hammer ( not on the crank shaft end of course)

Good luck bro

101gargoyles

I don't know sh.t but in the old days...
If you've been keeping up with your oil changes-even doing it 1/2 or 1/5 as often as you should, you may never need to replace the chain. The oil pump pumps oil so is therefore lubricated by it unless you run the engine dry and super hot a few times
Lower end noise is normal on that engine. It's design is as old school as you can get. Except for the fuel injection and electronic multi-coil ignition they're as solid as a rock.
Are you sure a chain problem even exists? Any chain drive on any machine requires a certain amount of slack due to the sling of the chain at high revolutions. For example, no slack then the shaft bearings take a side load. If a chain gets excessively loose it will probably wear out a vertical side on the cover and you'll then know something is real bad about to happen.
Worst that could ever happen is the chain jumps the sprocket teeth throwing the valve camshaft out of whack and the engine stops running.
AH but Grasshopper (google it kids) the 3.8 is not an interference engine design. HUH that means the valve heads never extend into the travel path of the piston heads.
Totally different story when most rubber belt driven cam shaft (high fuel mileage) engines. Don't change the belt on schedule and also the water pump on the way by and kiss goodbye to to the engine because when the valves get out of synchronization all the valves and pistons and cylinder heads become schrapnel.....Imported motors anyone????
This type of engine is the workhorse of the world where someone may have to do internal repairs with nothing but a piece of cardboard to keep the rain off them.
Don't get me wrong. The electronics to satisfy The greenies' air quality standards when they screw up in the middle of B-F Nowhere will get them to push it off a cliff so they don't have to stare at it on the side of the road forever. Let's not get me going about certain countries commissioning new COAL fired electrical power plants weekly
If people were stopping on the sidewalks and staring at your Jeep because the noise was blowing out their eardrums then go nuts and pull it all apart.
If not then now you know what the inside of your engine looks like-put it back together-and enjoy the Christmas season with stories of how you saw....things you can find when they actually break.

ronjenx

This is from the factory service manual for the JK 3.8L: "The engine does not have provisions for a free wheeling valve train."
I take that to mean it is an interference engine. Have you seen something to the contrary?

BulldogMJP

Soaked it in pb overnight. Did the trick . Gotta wait a few days for my timing chain set to arrive. My chain had way more deflection than the allowed 1/8 inch
Ill update when I do the install.

101gargoyles

Yes from an article back in 06 discussing the 3.8 being the engine of choice for the new Wranglers.
Would take some searching on my part and would prob have to scan to post. Just going from memory at this point. At the same time I'm doing that -- maybe someone can figure out how many timing chains on these engines required replacement under reasonable driving and lubrication conditions?

Found this article from 2007 talking about Chrysler interference and non int.. engines but still I could be wrong - Just saying will be a while before I search my files.

That is an engine, especially with a timing belt , that will damage itself if the timing belt breaks or slips. The valves and pistons are timed to just miss each other. If the belt skips a tooth or breaks while running, the valves will do an expensive dance on the pistons. It can get VERY EXPENSIVE to fix after this happens. This entails, not only putting a new timing belt in but removing the heads and redoing the valves. All the more reason to change timing belts when or before you are scheduled to.
The 3.5 and the 4.0 Liter engines in the Pacifica ARE interference engines.The 3.3/3.8L engines have timing chains and they are not.
I hope this helps.

webejeepin

OP nice tear down, good luck on the other side of the job, please post a pix or two.

Can see you have HOAT coolant there too eh.

07 Rescue Green

when you go to put it back together, put that bottom sprocket in the oven for a bit, it'll go on much easier.