602 enging timing chain
 

could somebody verify when the timing chain should be replaced on the 602 engine, i think some of my bad idle problems are from a worn chain or tensioner or both. there seems to be a clacking noise that comes & goes at regular intervals when the engine is at idle or higher rpm's "clacking intervals speed up with engine RPM.
as before the idle is very rough with # 5 cyl not firing until RPM is approx 1700.
There still seems to be a missfire " very intermitant " at the higher RPM. Cant see any air in the pre filter, no smoke, easy start's. this is a 1990 300D with 163,000 miles and full MB service history, i am thinking the owner sold due to being advised by the dealer it was time for some major cash to be spent on this vehicle!!!.
i have no problem doing the repairs but waht i do need is the chain link tool, this tool is over $450.00 from BENZ. Does anybody know where i can get same tool or tool that will do the job a little cheaper.

thanks very much

This is what I did....
 

I assuming that you already know how to replace the timing chain...but check the timing first...you may not need a new chain.

But if you do....

Turn the engine over to top dead center...

Lock the chain in place with a couple of vice grips on the cam sprocket...

Grind off a link...

Connect the new timing chain to the old one with the ground-off link...

Have a helper keep tension on the chain as you turn the crankshaft bolt pulling the new chain through the system...don't let it fall into the engine.

When the new chain is at the top of the camshaft sprocket, put the new link in...

If you're good with a ball-peen hammer, you could try to peen it over using a backup on the back of the camshaft sprocket...have your helper hold it firmly against the back of the chain....

OR

Sometimes, where you buy the chain, you can rent the tool...I paid a deposit on the tool and sent it back...

I've done it before...not that tough.

I hope this helps....

The Tenor Man

My knowledge on chain replacement is when the stretch exceeds the allowable limits for the engine, it's time to replace.

does anybody know the limits on a 602?

Yes, He should check the Timing Chain Stretch before speculating.

The Timing Chain Crimping Tool used to be in or tool Rental section.

If not you can buy the Tool on ebay. Note: there is a China version of the Tool but it does not cost that much less than the better one and I guess has Much less resale value.

timing chain noise
 

ok, timing is good, seems the tensioner is intermitantly leting the chain make noise. i have read on replacing tensioner, just a little qusetion ,, when replacing the tensioner does the engine need to be at TDC before removing the old unit.

thanks.

It's safe practice to have the engine at #1 TDC when working with the chain in case something goes wrong. Otherwise just remove the old tensioner, prime the new tensioner and install. Don't turn the crank, cam or IP while there's no tension on the chain.

Sixto
87 300D