So as the title states when should I change it, or should I change it at all? I've had so many people say no don't change, it then some say I'm past time for it to be changed..... I have a inline 6 4.0 with 130,0021 just got 130k today and it got me thinking about it more.... What do you guys think, when do some of you guys change yours..... Or did you not change it at all ??

 

For the most part it only needs changed under the following circumstances:
1. When it breaks.
2. When it gets so loose it is scraping the timing cover.
3. When you are doing other work that requires removing it, opening the cover to do other work, etc. (a might as well while you're at it thing).


The chains rarely fail and the 4.0L I6 is not an interference engine so it won't do any damage (aside from the chain itself of course) when it does.

 

I bought a salvage 4.0 with 138k. I checked everything I could....RMS,crank and rod bearings,oil pump and timing chain. Absolutely no wear on timing chain!! The 4.0 is a tough engine....I buttoned mine up without replacing anything except RMS.

 

My motor threw a rod @ 290k. I disassembled the engine & the chain looked good as new.

 

They stretch. Looks means nothing.

You start out at +4 degrees and after 130K you end up at -4 degrees.


Get a double roller next time.

 

730000 km on the Peep, 4.0 Renix never been unbuttoned. Runs daily, is the chain stretched. I am absolutely sure it must be. As I said, runs daily. So chain life is long. Perhaps extra long if you maintain a reliable schedule of oil and filter changes.

 

I guess I need to add, when I say "looks" I meant visually & functionally. There was no slack in the chain.

 

There are too many variables to make a statement like that. After 138k my timing slack at cam position sensor is still with-in spec.

 

If all is right with the world........don't fix it.

If he's going to tear it down for seals and gaskets.......and he's concerned about his timing set........

Cost what? $60 for a stock single roller?

Replace it.

 

Not so good-

 

Mine seems to be ok no strange noises or anything, guess I'll just keep it on there for now!!!! Thanks everybody for te great help and responses!

 

I just bought a 99 Cherokee base in amazing condition with 0 rust. It has 150K miles. Engine runs strong and not noisy at all. Should I have the timing chain inspected for slack? It is my first Jeep and I am totally ignorant of what needs to be done as preventive maintenance. Previous owner just had 4 new shocks installed and all bushings replaced on front end. Thank you in advance for any advice.

 

Since this has come back up 10 years later...

So as far as I can tell there is not a set interval for replacement. Driving style and maintenance routine are probably factors worth considering. The FSM for my 2000 XJ says, "(10) Installation of the timing chain with the timing marks on the crankshaft and camshaft sprockets properly aligned ensures correct valve timing. A worn or stretched timing chain will adversely affect valve timing. If the timing chain deflects more than 12.7 mm (1/2 inch) replace it."

I replaced the chain on my last XJ at about 200k. I did not measure the deflection but I feel certain it was not 1/2 inch. The vehicle had been babied its whole life and oil changed every 3000 miles.