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  #1  
Old 07-02-2003, 06:03 PM
Tom McMenamin's Avatar
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Need Technical Info and advice on SL engine work! Urgent

I have a 560 SL which is familiar to most of you here on Shop Forum. Today, I took my car into the Shop for the Timing Chain replacement as the car has 120K on the speedo. I wanted to be sure that I didn't have a chain failure.

The car was running like a top. Tach sat dead hard on 500 RPM and the car never missed a beat. I got a call at around 3PM and was asked to stop by the shop.

Seems that when the chain was replaced and the engine started a racket was coming from the engine which has been determined that the Valves were misaligned and had eaten into the head. Just 3 valves on the right hand side. As it looks to me, I have 3 burned and cracked valves on the intake side. May be two exhausts and one intake, not sure, I am busy vomiting while I write this note.

My question is how could I have valve and lifter (Stated that the lifters did not have the valves properly aligned) problems and the car run as well as it did? Could the problem be that a valve was bent when the chain was installed. They removed the head to repair the bent valve and decided that because of other damage that could be seen that it was time for me to pay for a valve job?


It really doesn't matter now as I have no choice but to do the work. however, is there any way to tell what caused the racket and the valve noise after the chain install. Can you see a bent valve and how do I get my hands on the bent valve to prove thats what happened?

Could it be that I had a serious problem waiting to happen or am I getting hosed into engine work I shouldn't have to pay for?

I'm not looking for sympathy just some technical understanding. It could be they bent the valve or valves and the inspection turned up the cracked valves and wear and that would need to be done sometime up the road.

Am I getting hosed or has a mistake turned up a problem that would have needed to addressed in the near term?

Who do you trust in this world and how do you know when you are being taken advantage or not? I guess that is the age old question.


Any and all advice and direction appreciated.
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Last edited by Tom McMenamin; 07-02-2003 at 09:26 PM.
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  #2  
Old 07-02-2003, 06:13 PM
engatwork's Avatar
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Quote:
Could the problem be that a valve was bent when the chain was installed?
Sounds to me like they let the chain miss a tooth on one side during the new chain installation if it were running good/smooth/no noise when you took it in.
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  #3  
Old 07-02-2003, 07:33 PM
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I know for a fact that the valve will not bend when the chain is off by 1 tooth. I believe it was off by more then 1 tooth when they started it up after the chain was replaced.Burnt or bent valves would not show up after a chain replacement. If you didn't have the problem before, you wouldn't have it now. I've been working on MB's for 16 yrs now and never found a burnt valve after I replaced a chain. good luck & dont't let them bend you over.
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  #4  
Old 07-02-2003, 08:47 PM
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How do I handle this problem? (See Previous Post)

This car has 121K and I use it every day for about 150 miles per day. The car runs/ran terrific. As I said it idles beautifully and performed quickly off the start and had super power at all speeds.

Here is my point of view on what has happened and I would like some comment from the group.

When the shop called me they said that they thought they had screwed up and that when they installed the chain they had done something wrong and bent a valve. They removed the head and put a level across the top of the valves and pointed out that one Valve was higher than the other. They say that this could have been the case for some time? I don't think the car would have run that well if that were the case!
Am I wrong or are their extenuating circumstances that the car would run great with this condition? Comments Please!

I believe that the chain was installed wrong and bent the valve. Now that the valve is bent you remove the head and look at the valve bottoms and you see cracking and some valve wear on 2 other cylinders. Rather than bite the bullet on bending the valve they go to me and say " You have valve issues and they need repair. We should remove the head and have it redone". It costs me money and they are off the hook.

The real issue here is that it is true that I saw valve cracking and some wear or debris on 3 of the valves. Two valves had a baked finish that was a tan ceramic color. I believe it to be the first and last valve in the head.

Based on the observation, I would probably be back to them in some months to have the valves done anyway. This episode just moved the head work up a bit.

The question I have is that even though it may have been good fortune to uncover the problem now, Why wouldn't they just admit the error and accomodate me some little bit. Would anyone in the business do that or am I a dreamer?

What would you do in these circumstances?

Another question: What causes the valves to crack and some to carbon up worse than others?
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  #5  
Old 07-02-2003, 09:36 PM
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The one valve was higher because its stem was bent and it will not fully seat into the valve seat.

You are being hosed - they screwed up the timing when the installed the new chain and did not check the basic timing before they attempted to start the engine. This is a HUGE oversight on their part.

They should fix this problem with NO cost to you. The only question in my mind is wether or not they are competent to fix the damage they have done to your car. Based upon their results of a timing chain replacement I would say NO.

Has this shop done work for you before?
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  #6  
Old 07-02-2003, 09:51 PM
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I agree!!

You are 100% correct I think we need some accomodation.

The guy has done alot of work for me prior to this. I was going to take it down to Donnie in Atlanta to get the chain done but figured after reading a great deal about the install it can't be that difficult. ( I defy you to find a Post on the Board that talks about Valve bending on timing chain installs)

It is my stupidity that cost me major bucks.

Gotta think this is my last stop at this shop!
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  #7  
Old 07-02-2003, 09:53 PM
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Consoling thought!

As I previously said, I probably would have needed the valve job down the road anyway! I just didn't need it Right Now!
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  #8  
Old 07-02-2003, 10:07 PM
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Pure speculation...

but my money says that when the chain was rolled in, a guide wasn't used. What happens then is the chain jumps at the right cam. The next time it jumps whicle rolling in will cause the valves to contact the pistons. That is why, on almost every t-chain DIY response you read you see the suggestion to roll the crank over two complete rotations (a complete cycle). If the cam timing is off you won't be able to make 2 rotations by hand AND if you don't do 2 rotations by hand you won't know if the cam timing is off (and if you did everything right and didn't have the chain jump, 2 rotations will be smooth and easy).

Now, have they looked at the left bank? That is the side that usually eats it when a chain goes.

I would argue the labor involved and the bent valve(s) are the shops bill, I would also suggest doing a complete valve job of the rest while the car is apart (your bill).
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  #9  
Old 07-02-2003, 10:16 PM
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Many thanks Mike!

Yes, I went and looked at the problem and asked about the drivers side. He mentioned that it might not need work. I said, take the head off and lets look and see. I'm going for both sides while we are here at this point!

What we have developed here is a trust issue. I have no faith now in the shop. Better late than never! I'm going by again in the morning to check to see if he pulled the other head. I just might keep my mouth shut until I get the car back on financial adjustments.

The other issue is I need to go to the machine shop and look at that tomorrow as well.

Thanks for the reply. I respect your opinion. Always have!
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  #10  
Old 07-02-2003, 10:45 PM
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What is the name of the shop.?

Scott
Baltimore
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  #11  
Old 07-02-2003, 11:09 PM
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Hunt Valley Imports, Chris Connelly

Not Hunt Valley Motors!
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  #12  
Old 07-03-2003, 08:41 AM
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Quote:
thought they had screwed up and that when they installed the chain they had done something wrong and bent a valve
There you go.
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  #13  
Old 07-03-2003, 09:30 AM
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Its their problem no matter the cause.

We have done hundreds of valve jobs and thousands of chains. It doesn't matter what happened since they were in control. Believe me a MB v8 with 120k needs neither a valve job or a chain. The only thing it realy needed was upper chain rails.

About 20 years ago I got my first taste of reality on this subject. We did a preventative chain and tensioner (no rails). About a month later the car had a ignition problem (maybe even caused by our work - the green wire from the distributor to controller was intermittantly shorting to the valve cover. During a time of deficient ignition the thing dieseled and ran in reverse direction for a moment. Happens quite frequently with such problems. The rails broke and while trying to start the car the valves on the left side bent.

So whose fault is it? Doesn't matter. We did the one and only free v8 valve job in the 25 years we ahve been in business.

There just isn't anyway to justify doing preventative maintenance that includes doing the work that was to be prevented. I am trying to point out that this is not a technical issue. The technical issue is moot. This is a business issue at this point. Fault has no part in it.
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  #14  
Old 07-03-2003, 10:56 AM
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Thanks, Steve!

I just left the shop after mulling this over all night.

What really upsets me is the fact that yesterday the mechanic(owner) tells me that the valve was like that before the chain was done. What that says is that I am STUPID. I am just a stupid customer that will believe whatever I am told.

My problem right now is that the Head is off, the other Head is in process of being torn down, and I am facing a big price tag.

The money and the valve job are not the issue. As Steve points out it is not now a technical issue. The shop has lost all technical credability.
I can't be sure that the work he must now do to rectify the problem will be done honestly and reputable and when the job is done and the bill is paid, in what condition will the car be.

Should I tow it out of there? Should a novice like me watch every step of the repair? What would I see? What do I know? The majority of us out here know enough to be dangerous. This is a real problem. How do you know when the bolts are all in and the car sits running in front of the shop that did the work, that when you drive away with an empty wallet you are behind the wheel of a time bomb waiting to go off?

I don't know! What a dilemma!

Many thanks to all on this Board that contributed to my help in the above and thanks to all who try in their own way to help another. That is what these Boards are for and it speak volumes as to the members of this Mercedes Shop fratenity.

Thanks to all as I am off to the bank to get the blood money to pay in a week or so. What sort of accomodation will be made? It remains to be seen. I'll keep you POSTED!
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  #15  
Old 07-03-2003, 11:06 AM
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You need a second opinion and you need it before it goes back together.
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