[rondak46]

I am thinking about changing the timing chain in my '00 4.0. I am thninking it would be a good idea to do the water pump at the same time. Do I have to remove the radiator to do this. I am just trying to scope out how much time I will need to complete the job.

Thanks, Mike

[Fett]

Yes, you would have to remove the radiator. But why do you replacing the timing chain? If it ain't broke, I wouldn't touch it.

[Jerry Bransford]

Don't confuse the Jeep's heavy steel timing chain with the rubber timing belt used by most cars. While a rubber timing belt needs to be replaced at 60-80K miles, the Jeep's timing chain isn't touched until the engine requires a complete overhaul. That doesn't even start to be a common thing until at least 250K miles on a properly maintaned engine.

[Eric06Rubi]

x2 on the radiator removal , and if your over 80k on the engine a chain may not be a bad idea. and yes , do the pump while your there.

You should be able to ge r done on a saturday morning if you have some mechanical ability. I'm guessing about 4 hours if all goes well, including drytime for the RTV.

[Jerry Bransford]

Originally Posted by Eric06Rubi

and if your over 80k on the engine a chain may not be a bad idea.

Read post #3 above.

[Zew]

I recently replaced the timing chain on the 4.0 i yanked out of my 1998 TJ. I re-used the 4.0 engine in a 1998 GC i bought off of craigslist for super cheap. I had the head re-done, replaced the oil pump, and did the timing chain. Mine was suprisingly lose. It only had 186k on it. Runs like a champ now. No more misfires like when I had it in my TJ. I guess it all depends on maintenance. I was the 2nd owner of my TJ so i have no idea how well the guy took care of it.

[rondak46]

With 150K plus miles on the timing chain I think it would be a good idea to replace it. With that kind of mileage there has to be some stretching going on and I don't want it to mess up valve timing. That is why I am doing it. The water pump is a "while I am in there" kind of thing.

Thanks for the advice all.

[George Dickel]

Originally Posted by rondak46

With 150K plus miles on the timing chain I think it would be a good idea to replace it. With that kind of mileage there has to be some stretching going on and I don't want it to mess up valve timing. That is why I am doing it. The water pump is a "while I am in there" kind of thing.

Thanks for the advice all.

Have you ever seen a timing chain? I'm not saying it won't stretch but I've never heard of changing one unless there is an engine rebuild occurring. This is not a task for the faint of heart either.

[George Dickel]

Originally Posted by rondak46

I am thinking about changing the timing chain in my '00 4.0. I am thninking it would be a good idea to do the water pump at the same time. Do I have to remove the radiator to do this. I am just trying to scope out how much time I will need to complete the job.

Thanks, Mike

Not only will you need to remove the radiator but EVERYTHING else from the front of the block. This will include your crankshaft pulley and the timing chain sprockets from both the cam and the crank. Honestly, if you think it would be a good idea to change the timing chain, you should go ahead and rebuild the motor while you're there. Otherwise, I would save up, plan it out and then rebuild. Obviously this is not something you would do unless you either really had to or because you wanted to Stroke your motor. The latter is what I did. If you're still hell-bent on changing the timing chain, figure on a serious set of tools, some pullers, a really good manual, and lots of time (unless you're really experienced). This is the 2 cents from someone who's done the task.

[GOLENJEEPTJ]

Wait on your timing change, till your ready to do the engine complete!There's no need if all is fine now!It's like Jerry and George said above.

[Unlimited04]

Originally Posted by rondak46

I am thinking about changing the timing chain in my '00 4.0. I am thninking it would be a good idea to do the water pump at the same time. Do I have to remove the radiator to do this. I am just trying to scope out how much time I will need to complete the job.

Thanks, Mike

why do you want to replace the timing chain? they are good for the life of the engine, so wait until its time to rebuild the engine.

[rondak46]

Originally Posted by George Dickel

Have you ever seen a timing chain? I'm not saying it won't stretch but I've never heard of changing one unless there is an engine rebuild occurring. This is not a task for the faint of heart either.

I have seen timing chains.

You have NEVER heard of changing a timing set outside of a rebuild? That surprises me. They do get loose after a while and can cause valves to be open or closed when they are not supposed to. To be sure, I replace stuff premptively, and I would say that changing a 4.0 TC set out after 130k is not unreasonable. The problems caused by loose TC set can cause major perfomance and mechanical issues. I want the next 100k on my 4.0 to be a hearty run, not a downhill slide.

[rondak46]

Originally Posted by Unlimited04

why do you want to replace the timing chain? they are good for the life of the engine, so wait until its time to rebuild the engine.

I do not agree with you, If they have seen a lot of hard work and a lot of miles they can cause a decrease in performance.

Cheers, Mike

[Zew]

Changing the timing chain isn't really that big of a deal. The only thing that sucks about doing it is that the oil pan rests on the timing chain cover, so you have to use the replacement section of the gasket supplied unless you decide to replace the whole oil pan gasket. That's really the worst part of it.

Serious set of tools... not really. You buy an el cheapo harmonic balancer puller/installer from the auto parts store, hell... even rent one... and all you need besides that is regular standard and metric sockets.

[George Dickel]

Originally Posted by rondak46

I have seen timing chains.

You have NEVER heard of changing a timing set outside of a rebuild? That surprises me. They do get loose after a while and can cause valves to be open or closed when they are not supposed to. To be sure, I replace stuff premptively, and I would say that changing a 4.0 TC set out after 130k is not unreasonable. The problems caused by loose TC set can cause major perfomance and mechanical issues. I want the next 100k on my 4.0 to be a hearty run, not a downhill slide.

Only on racing engines. Can't recall any preventive maintenance timing set changes. Just saying...