617 Valve adjustment turned into a nightmare.:( - PeachParts Mercedes-Benz Forum

82300sd · #1 04-22-2008, 12:49 PM

I brought my car, 1982 300SD, to my mechanic for a valve adjustment. While cooling the engine down with the valve cover already removed, he noticed that my camshaft sprocket was installed incorrectly. It was inside out which made the chain misaligned and already ate some part of the engine block. It's been like that since I bought it 3 years ago.

He decided to fix it by removing the tensioner and the front covers including the vacuum pump and cautiously reversed the sprocket. I asked him if it I needed to change the chain since it has already rubbed with the engine block and it might already be brittle. He said that they usually just reverse the sprocket without any problem whenever they encountered a problem like this. He then put it back together and proceeded with the valve adjustment.

Engine fired easily and I noticed it to be quieter and the minor engine shake disappeared. We decided to do a test drive together and as we went out of the shop, i stepped on the pedal harder than usual and we heard a pop. Engine died and we coasted beside the road. Turned out later that the timing chain broke and so did the camshaft, one camshaft bearing, etc.

I was speechless when I saw it after they removed the valve cover. I was so down when I left the shop thinking that I only went there for a valve adjustment and suddenly this happened. I still don't know if they will shoulder the repair or tell me that chains do break and they are not to blame.

What could have gone wrong?

pawoSD · #2 04-22-2008, 12:53 PM

It was likely the previous issue that caused it. Timing chains do indeed break........it was not caused by the valve adjustment....

82300sd · #3 04-22-2008, 01:06 PM

I agree that the valve adjustment has nothing to do with it. I'm trying to determine if they have a part in it (mis installation or something to that effect) or just another bad day for me. I would have no problem accepting it had they NOT touched it.

MBeige · #4 04-22-2008, 01:15 PM

Bong, Patrick here over from MB Club PH. I'm sorry to hear about that. I hope if the chain broke the valves are intact, otherwise it'd be a top overhaul for your SD. I guess when the mechanic saw the improperly installed sprocket, at that point the most viable thing was to have the timing chain replaced since it was already grinding on the engine block. Have that done as well as the tensioner, reverse the camshaft sprocket, redo the timing and you're good to go.

At least it happened as you were testing it, and not on another one of your long journeys.

82300sd · #5 04-22-2008, 01:22 PM

Hi Pat, I suggested to change the timing chain but he said the timing chain is still good and they just usually turn over the sprocket. The valves are intact. Camshaft will be replaced together with the sprocket, tensioner, railings, etc. Instead of just paying $12 for the valve adjustment, I'm looking forward to my bill that will not go lower that $500.

tangofox007 · #6 04-22-2008, 01:31 PM

Quote:

Originally Posted by 82300sd

Hi Pat, I suggested to change the timing chain but he said the timing chain is still good and they just usually turn over the sprocket.

Is there an epidemic of reversed camshaft sprockets in the PI? I would suspect that the typical mechanic could work on 617 engines for several thousand years and not see a reversed sprocket.

There is something wrong with this picture.

82300sd · #7 04-22-2008, 01:44 PM

Quote:

Originally Posted by tangofox007

Is there an epidemic of reversed camshaft sprockets in the PI? I would suspect that the typical mechanic could work on 617 engines for several thousand years and not see a reversed sprocket.

There is something wrong with this picture.

There are a few experienced MB mechanics here as there are also a handful of MB's here compared to rice burners.

vstech · #8 04-22-2008, 02:17 PM

Quote:

Originally Posted by 82300sd

There are a few experienced MB mechanics here as there are also a handful of MB's here compared to rice burners.

what does that mean? are you saying that it's common for the cam sprocket to be reversed? give me a break!
there is NO WAY I would have allowed a timing chain that was rubbing against the block to be re used. also, I would be eyeing the oil pump, tensioners and anything else in there that would be getting iron filings from the wear!

the mechanic reccomended against replacing the chain! HE is responsible. go to HIS boss and get the valves/etc replaced for free!

JimmyL · #9 04-22-2008, 01:25 PM

Timing chains don't really break all that often, but the fact that it did immediately after the work performed simply is a coincidence that can't be stomached!!
At the very least the advice not to replace the chain was faulty, but something was done during this to cause the chain to break, ie: sliding off tensioner or some other issue. Proceed from a standpoint point of "what are yall gonna do about this".....

82300sd · #10 04-22-2008, 01:36 PM

Quote:

Originally Posted by JimmyL

Timing chains don't really break all that often, but the fact that it did immediately after the work performed simply is a coincidence that can't be stomached!!
At the very least the advice not to replace the chain was faulty, but something was done during this to cause the chain to break, ie: sliding off tensioner or some other issue. Proceed from a standpoint point of "what are yall gonna do about this".....

That is precisely my point, Jim. Had it happened without them touching it is easier to accept. Tha't why I am asking what could have gone wrong after reinstallation?

When I asked him "What are you going to do about it?", he just answered that chains do break and that if something is wrong it should have not started and idled better than before.

Jimmy Joe · #11 04-22-2008, 09:00 PM

That mechanic messed up. After seeing what he saw, putting it back together with worn chain, then claiming "chains break!!! WTF!!!

Not cool.

Mustang_man298 · #12 04-22-2008, 10:01 PM

There was a sequence of events which caused this, it is not just one man's fault.

The first cause was whoever installed that sprocket incorrectly. The second cause was being driven that way over that extent of time, allowing the chain to wear on things and become accustomed and worn to the irregular stress pattern, probably causing uneven stretch from one side of it to the other and causing it to wear more on one side. The 3rd cause was failing to tell the mechanic that it WILL be replaced now regardless of his opinion because we all know how parts that have been run in compromised situations are now compromised parts. Lastly, straightening the sprocket disturbed the chain, and now reset it to the original wear pattern, which it was not used to, and now placing a new stress pattern on a likely weakened chain due to improper wear, aside from now being made to want to ride out of the grooves it had most recently worn into the tensioner pads.
What I'm saying is, it was damaged, it was weak, and may or may not have lasted a while as it was had it been left alone, but it was only borrowed time, and halfway fixing it is exactly just that.

The circumstances suck, and you might be able to convince them to absorb it, not likely, but you might be able to get a bit of a discount at least. That mechanic can suggest things, but ultimately it is the owners responsibility to choose the work he does/does not want done. The true realistically liable party for this happening was the one that created the initial sprocket problem.

82300sd · #13 04-23-2008, 03:00 AM

Quote:

Originally Posted by Mustang_man298

The circumstances suck, and you might be able to convince them to absorb it, not likely, but you might be able to get a bit of a discount at least. That mechanic can suggest things, but ultimately it is the owners responsibility to choose the work he does/does not want done.

I have already given them $400 to buy the parts needed. That is still exclusive of labor charges. I will go there this afternoon and see how things are working around. This is a lesson learned for me of not insisting on replacing the chain. They are the authority on this and I trusted they know better. I will certainly replace it had they suggested. I should have asked for the consequence of a chain break coz had I known I would have insisted that it be replaced.

barry123400 · #14 04-22-2008, 10:11 PM

Another vote for doing your own work. Things can still go wrong but at least the costs are usually more controlled and you only have yourself to blame then.
My guess is when the chain was running one side was wearing against metal as you stated. As soon as it was runnning straight a link with the ends ground down pretty bad slid back out. Whatever tension was holding the link in was removed. A good visual inspection of the chain might have seen the problem.
The real fault here was at some time someone did not assemble the engine properly. Too bad you have to bear the ultimate cost of that.
Also since the chain was rubbing on one side eventually it would have failed probably even if left as it was. I also understand how tough it is when these situations arise.

Diesel911 · #15 04-23-2008, 12:49 AM

The Philippines explains the $12 cost to have a Mechanic do the valve adjustment.
My Wife (12 years now) is from the Philippines and I have spent about 60 days there. During that time every car (especially Taxies) I rode in had badly slipping clutches and a multitude of other problems. The impression that I got is that if the vehicle moves at all nothing is going to be fixed.
My Wife also tells me that unless a Doctor did something extremely out of line (like Murder) there is not even possible to sue for malpractice in the Philippines.