replacement timing chain on 603?
 

I'm helping my father out with his 87 300SDL(603.960). While I was visiting him in AZ earlier this year his car started blowing smoke like a battleship. Long story short, it turned out to be a blown (exhaust) valve seal. We pulled the head and had a shop do the valve job. Now dad's putting it back together. At 247,000 miles, he decided that "while I'm already in there", he'd replace the timing chain. I can't argue that logic since I'd do the same. The thing is that the new chain is much lighter than the old chain. It looks like it should be in a gas engine rather than a diesel. It even has a clip type link to close the chain rather than the old rivet type. The "indy" MB parts place he got it from verified that they sold him the right chain, he even called a couple of MB dealers in his area and they told him he has the right part, and that the new part is different from the original, they just didn't know what the difference is. He's tempted to keep his old chain since it looks so much stronger, but he's at a point now where he can't verify the stretch without doing a bunch of work he'd have to undo if he needs to replace it. What do you guys think? Have any of you used the new "lighter" chain? Any input/opinions would be appreciated. TIA.

I didn't know the '87 300SDL came with an OM603.960?

Is the clip meant to close the chain for service use or as a facility for rolling in the new chain, then peen the link to close it permanently? If you check the Buy Parts link (no pun intended) at the top of the page, you'll see that a peen type link is available separately from the chain.

You might as well button up the engine with the existing chain and check elongation. If necessary, you can roll in a new chain without taking the engine apart. Only the valve cover has to come off.

Sixto
87 300D

I might be off on the model year, dad's had too many MBs for me to keep track of.

Yes the clip is designed to be permanent. I know that peen links are available, but none of the peen links at his local MB dealer would fit the replacement chain, they're all way too big, and the parts guy told him he doesn't have a listing for a peen type link for that chain, it only comes with the clip, which you cannot buy seperately. It sounds strange to me that a lighter chain would replace the original, but that seems like what MB has done.

Then buy a chain and link set from Phil through the link above like the rest of us do and sleep easy :)

Sixto
87 300D

I'm just wrapping up a 603 rebuild out of an '87 SDL. The replacement chain I got from Phil (buy parts link above) was identical to the chain I removed.

I'd ask the dealer to print you out the notes from the Star Tek data about why the chain is different. Something sounds amiss.

It sounds to me like you have a double-row timing chain for a GAS engine, not for the DIESEL. In the photo below, you can see clip-type master links for (left to right) single-row gasser, double-row gasser, and double-row diesel. The chain you install must be identical to the chain you remove or you'll be in deep doo-doo. The current chain part number is 003-997-55-94. BTW, the 300SDL has an OM603.961... the 1987 300D has an OM603.960. There's almost zero difference between them though.

If the chain you have is not IDENTICAL in size to the one in the car, DO NOT install it.


http://www.w124performance.com/image...ain_tool09.jpg


Here's a photo of the correct chain:
http://img.eautopartscatalog.com/live/A510088310IWI.JPG

You either have the wrong chain or some cheap aftermarket one. I rolled a timing chain onto my 603 a few years ago and the new chain was identical in every way to the old one. But I didn't mess around I went right to the dealer and got a chain. MB makes a special tool which you can rent on this site to crimp the new chain over. You should not be able to tell which link is crimped if you do it correctly.

Don't forget to replace the tensioner and whatever guides you can get to.

That parts guy is spouting pure, weapons-grade baloneyum. The correct peen link has a pressed-fit center plate, instead of a slip-fit plate. The clip-type link is NOT supposed to be used on a running engine, it is sold only as a "tool" for termporarily attaching the old chain to the new, while rolling the new chain in.

The proper part number for the diesel peen-type master link, with press-fit center plate, is 000-997-28-98. And no, the chain has NOT been replaced with a lighter part. If you go back, make sure you talk to a DIFFERENT parts guy, or the parts manager. You need to return the chain you have now, and buy the two part numbers I mentioned above.

:hammer:

Thanks guys, pretty much what I was thinking. As far as baloneyum, 3 different sources have been providing that info, maybe they're all reading the same typo error from thier source. I'll tell my dad to get another chain, the part# should come in handy. Thanks agian.:thumbup:

Any chance you can tell us what part number they sold him? I'd love to look it up and find out what it is...

:ninja:

What part number is on the chain that you have in hand?

Now this sucks, the part# that my dad has is the correct #. Just talked to Phil and he quoted the same part# from memory(wish my memory worked that well). Said it should be the same chain as what he has in the car, also recommended I talk to Roy to see if Roy knows something he doesn't. I'm waiting to hear back from Roy now. I'll let you know what I find out.

It could be the wrong label on the box, or the wrong part in the box. Wouldn't be the first time that's happened. Any chance you could take a close-up photo of the chain (better yet, BOTH chains next to each other) so we can see the size? If you can't post it, you can email it to me, I can host the photo on my website...

:stuart: