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.

JimmyL · #6 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".....

tangofox007 · #7 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 · #8 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.

82300sd · #9 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 · #10 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!

tangofox007 · #11 04-22-2008, 02:31 PM

Quote:

Originally Posted by vstech

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

My guess is that you haven't done much business in the Philippines.

82300sd · #12 04-22-2008, 02:31 PM

Quote:

Originally Posted by vstech

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!

I guess it is not common but they already handled a "FEW" cases where they just turn it over without adverse effect.

I also asked about the iron filings and he said that its not a problem since it will be handled by the oil filter. Would that be the case?

JimmyL · #13 04-22-2008, 02:47 PM

Quote:

Originally Posted by tangofox007

My guess is that you haven't done much business in the Philippines.

It doesn't seem uncommon that most humans wouldn't have done much business in the Philippines. What is the point with that one Tango.....

Knightrider966 · #14 04-22-2008, 03:04 PM

Unfortunately I've seen some home and backyard mechanics put the upper sprocket on backwards! I bought my 240D this way. Good for me that it was timed wrong and wouldn't start, so I got a great deal since it was not driveable, but I would have replaced the chain.