Just got my Wagon.... one potential issue. - PeachParts Mercedes-Benz Forum

ambush276 · #1 07-14-2016, 09:49 PM

Picked it up today. Has around ~280k on it, meticulous service records since '95. Everything has been done/looks good... except i see NO record of the timing chain being replaced. They even redid a lot of the rubber. Paint needs a little help in the rear quarter driver's side. Beyond that it looks like a keeper.

I am a little nervous about doing the timing chain myself as it's such a critical.. if you screw it up.. you're engine is toasted.

If i buy a timing chain how much should labor be. I also don't have some of the specialty parts to do it. Since it is such a "not so often" job... i am not sure if it's worth investing in the tools in the first place.

How hard is it really?

(1984 300td)

dieselbenz1 · #2 07-14-2016, 10:07 PM

Interesting question you pose I have seen 3 mercedes equipped with 617.9 engines over maybe the last 5 years for sale locally in the classifieds all claiming to have new engines installed due to the dealer making a mistake installing the timing chain. Nice to have that kind of insurance or backing for sure.

Congratulations on your new vechile.

Rogviler · #3 07-14-2016, 11:49 PM

The timing chain was one of the things that I had the most anxiety about doing, but turned out to be pretty straightforward. I didn't even make a fancy guide, just some scrap wood and screws. Worked fine.

The hardest part was finding a chain tool. Any of the cheap ones will NOT work to crimp that type of chain, despite the threads suggesting them. And in the end I didn't use one, just ground the ends off a link and then when I put the final link in I just peened it. So totally doable without any special tools.

-Rog

dude99 · #4 07-14-2016, 11:52 PM

Have you checked your chain stretch? It probably does't need replacing.

leathermang · #5 07-15-2016, 12:02 AM

Quote:

Originally Posted by Rogviler

..... I just peened it. So totally doable without any special tools......-Rog

perfectly acceptable procedure.

ambush276 · #6 07-15-2016, 12:44 AM

Quote:

Originally Posted by dude99

Have you checked your chain stretch? It probably does't need replacing.

engine has 200k+ miles ... no records of the chain being replaced.. I am going to check the stretch this weekend though.... pretty confident it will need replacing.

leathermang · #7 07-15-2016, 01:03 AM

There are a few simple rules.... if you follow them you should have no problem replacing the chain.
Keeping tension on the chain as you install is one rule.
keeping the chain against the cam sprocket is one rule.

Check the rental forum on this site... the fancy tool for the cam sprocket might be rentable......I think someone even made one themselves...
However, it is really wise to replace the parts which are in contact with the chain... as the chain itself seldom breaks... but problems happen when one of those parts implode...

charmalu · #8 07-15-2016, 01:18 AM

Congrats on the new Wagon. If you paid less than $1000 for it you can join the cheap Wagon Club.

Here is a thread, 9 Deg of chain stretch that CELL did a few years ago.
Lots of DIY, getting down and dirty and replacing everything.

Good read even if you don`t want to go this way.

http://www.peachparts.com/shopforum/diesel-discussion/305365-9-degrees-chain-stretch.html

I broke a chain once, know what that feeling is like.

Doing 65mph and...what`s that noise???

By then it is over, even before I said wh...

Charlie

vstech · #9 07-15-2016, 07:33 AM

Pull the valve cover, inspect the weather on the guides, and check the stretch... If it is well maintained, it could easily be zero stretch.

Chains fail/stretch from wear... Quality oil and oci and it gets no wear.

ambush276 · #10 07-15-2016, 11:23 AM

Quote:

Originally Posted by vstech

Pull the valve cover, inspect the weather on the guides, and check the stretch... If it is well maintained, it could easily be zero stretch.

Chains fail/stretch from wear... Quality oil and oci and it gets no wear.

so you're saying that if the chain looks ok from visual inspection and the upper guide rail looks ok... and stretch is ok... don't replace it?

I mean theoretically it could have been replaced and there is just not record of it.. but i mean the records are pretty detailed since '95... Would be surprised if someone forgot to mention that.

BWhitmore · #11 07-15-2016, 11:43 AM

Hate to add to your worries, but the vacuum pump is something to check also.

vstech · #12 07-15-2016, 11:51 AM

My sd with original chain had 2degrees stretch at 550+k, and still going strong... under new management...

leathermang · #13 07-15-2016, 12:32 PM

Quote:

Originally Posted by ambush276

so you're saying that if the chain looks ok from visual inspection and the upper guide rail looks ok... and stretch is ok... don't replace it?

I mean theoretically it could have been replaced and there is just not record of it.. but i mean the records are pretty detailed since '95... Would be surprised if someone forgot to mention that.

Those things are possible ....
It is YOUR LOSS if you guess wrong...
suggest you use the threads in my signature and check the chain elongation...

snapped_bolt · #14 07-15-2016, 12:41 PM

But as it has turned out, with other measurements I took, I replaced more than the chain. The chain had to go regardless of stretch, it was made for a gas engine. Gas engine chains are smaller in all dimensions with the exception of overall length and pitch. At least 30%.
I replaced all guide rails, only one looked "new". I replaced the tensioner rail because it was worn to bare metal. I replaced the tensioner itself as it couldn't hold tension on a kid's bicycle chain. Since the timing device was exposed during repairs, I measured the end play and found it about 5X the max allowed by Mercedes, so I changed the bushing behind it. While there I noticed the "thrust piece" for the oil pump bushing worn badly, so I replaced that while I was in there.
It's all going back together now. I also had to remove the injection pump because of a "healthy" leak at the block gasket, and I will be drip timing it today.
The chain refused to continue once I had replaced the tensioner. Three link plates fell to the oil pan, and some chain debris was ground up and deposited in the oil pan. The chain then had to be removed; I am fortunate that I noticed the chain failing before it broke.
If you follow the Wikka chain stretch checking procedure be aware it is not entirely what the service manual describes. You should take measurements perpendicularly with the dial indicator, and this cannot be done without extensions for the indicator tip so the dial housing will clear the camshaft lobes as it is being turned. Extensions are usually available on Ebay for cheap ($5?)
Once I have this all back together, I can finish what I started, and check my final chain position after all adjustments are made. But it should be close after refreshment, right?
I would definitely check the chain with that many miles racked up on it.

Cheers,

snapped_bolt

ambush276 · #15 07-15-2016, 02:18 PM

Quote:

Originally Posted by BWhitmore

Hate to add to your worries, but the vacuum pump is something to check also.

was reconditioned 2 years ago