161k Do I need to change my Timing Chain?, damaged Injection Pump Timing device - Page 2 - PeachParts Mercedes-Benz Forum

Hatterasguy · #1 09-20-2007, 12:24 AM

Check the stretch. But on a 160k mile 603 their is probably very little. Put another 100k miles on it then start thinking about changin the chain.

I'd worry more about the vacuum pump, is it the old style?

87tdwagen · #2 09-21-2007, 02:35 PM

I would check for stretch the eyeball method first and dig in deeper if not happy with those results. I followed the often mentioned procedure of lining up the camshaft and crank marks on mine at 220k, original chain and they lined up to Zero eyeball stretch, if I had more than 2 deg I would have gone into it per the FSM.

Just make sure to do it multiple times and average your readings, I did mine 5 times over each time showing zero so I'm not concerned. Eyeballing it should get you to within 2 degrees of precision. Since the tolerance limit is 4 degrees I'd recommend checking it with a dial indicator if eyeballing it gives you 2 degrees or more of stretch.

777funk · #3 09-17-2007, 01:08 PM

So far this is what I will change (chain related):
Chain (of course)
Tensioner
Vac Pump

Anything else adviseable?

vstech · #4 09-17-2007, 01:50 PM

oh yeah, I remember your post! but a 617 this problem is WAAAAAY more rare than on a 603. a 603 has that set of bearings just sitting out there and just a little wear and they go all over the motor destroying stuff left and right!

Stevo · #5 09-17-2007, 03:35 PM

A friend of mine that is on this list found ball bearings in his "early" 616 oil pump screen,

indicating a past catastrophe caused by his diaphragm type VP.

#6 09-17-2007, 03:39 PM

Quote:

Originally Posted by vstech

oh yeah, I remember your post! but a 617 this problem is WAAAAAY more rare than on a 603. a 603 has that set of bearings just sitting out there and just a little wear and they go all over the motor destroying stuff left and right!

I agree that it is much more likely on a 603, and the consequences are likely to be much worse. I just didn't want to give the 61x owners the impression that it's OK to ignore a failing vacuum pump.

barry123400 · #7 09-17-2007, 07:56 PM

There are many reasons not to just change the timing chain without checking it. The most important is what if the previous owner changed it say 10k ago? Then just a waste of money.
More important is to inspect the chain guide in my opinion. If the chain checks good. There is no really sensible option to getting a proper chain stretch reading. To be accurate you have to make sure that an offset key has not already been installed on the cam. They tell me harbour freight has a dial gauge and magnetic base for about twenty five dollars on sale. Useful for other things as well over the years.

t walgamuth · #8 09-21-2007, 06:34 AM

Quote:

Originally Posted by barry123400

There are many reasons not to just change the timing chain without checking it. The most important is what if the previous owner changed it say 10k ago? Then just a waste of money.
More important is to inspect the chain guide in my opinion. If the chain checks good. There is no really sensible option to getting a proper chain stretch reading. To be accurate you have to make sure that an offset key has not already been installed on the cam. They tell me harbour freight has a dial gauge and magnetic base for about twenty five dollars on sale. Useful for other things as well over the years.

I agree with this. Never change anything you don't know is bad, mercedes parts are just way too expensive.

Tom W

t walgamuth · #9 09-21-2007, 06:33 AM

Quote:

Originally Posted by Craig

I agree that it is much more likely on a 603, and the consequences are likely to be much worse. I just didn't want to give the 61x owners the impression that it's OK to ignore a failing vacuum pump.

It happened to me too. So it is not that uncommon.

Tom W

777funk · #10 09-22-2007, 11:24 AM

I read that Craig's mechanic had somehow moved the IP when the vac pump was removed. I think on my 603 the bolts that hold the Vac Pump also are Injection Pump fasteners that are loosened for timing??? Is that right???

If so, how do I avoid messing with my pump timing when I change the Vac Pump?

Stevo · #11 09-22-2007, 12:13 PM

Quote:

Originally Posted by 777funk

I read that Craig's mechanic had somehow moved the IP when the vac pump was removed. I think on my 603 the bolts that hold the Vac Pump also are Injection Pump fasteners that are loosened for timing??? Is that right???

If so, how do I avoid messing with my pump timing when I change the Vac Pump?

Your IP MAY have a place for a "locking pin" someone will chime in. Its good to learn how to do the timing, not really a big deal once you go through the learning curve and do it once, epically if you have the "pin"

#12 09-22-2007, 12:43 PM

Quote:

Originally Posted by 777funk

I read that Craig's mechanic had somehow moved the IP when the vac pump was removed. I think on my 603 the bolts that hold the Vac Pump also are Injection Pump fasteners that are loosened for timing??? Is that right???

If so, how do I avoid messing with my pump timing when I change the Vac Pump?

Just to be clear, you can remove the vacuum pump without affecting the IP, he actually had to remove the IP timing device (behind the vacuum pump). That's the thing that drives both the IP and the vacuum pump and controls the IP timing advance based on engine speed.

777funk · #13 09-22-2007, 02:08 PM

Ok... I wonder why he removed that? I've changed a vac pump on a previous 123 300d and I never removed the IP timing device.

Also, on the 603 in my 124 300d I see that the Vac Pump is just bolted on with other bolts. Not the three bolts that are loosened to adjust IP timing. So shouldn't be too bad.

I really cut my arms up getting the fan off though. That 8mm allen bolt is a pain to loosen. NO CLEARANCE!!! Ouch!

I found a great way to break it free though. I taped an 18" piece of conduit as a breaker bar to my allen wrench, supported it well and had my wife click the motor over very quickly. I had to be VERY careful of course. But it worked great.

Quote:

Originally Posted by Craig

Just to be clear, you can remove the vacuum pump without affecting the IP, he actually had to remove the IP timing device (behind the vacuum pump). That's the thing that drives both the IP and the vacuum pump and controls the IP timing advance based on engine speed.

#14 09-22-2007, 03:47 PM

Quote:

Originally Posted by 777funk

Ok... I wonder why he removed that? I've changed a vac pump on a previous 123 300d and I never removed the IP timing device.

It was the IP timing device that was the problem, it had too much axial free play so that it was getting pushed back and forth by the vacuum pump. I had a little clank sound (I thought it was a loose valve) when it hit the thrust bushing behind it.