380SL - when the timing chain breaks?

I have a 380SL, 37k miles, and was wondering what are the syntoms when the timing chain breaks? Is there a notice giving an advanced warning? Say the chain breaks, what are the results - cost, engine damage, etc?

What is the cost to put in the "dual timing chain"? What happens if the "dual chain" breaks?

My 380SL is strong and purrs like a kitten but it is 21 years old. Is the chain metal or some sort of fiber? Does age without regard to milage affect the reliability of the chain?

How much does it cost to replace the chain? Only Mercedes can do it?

Reply to
Ptolemy
Loading thread data ...

A very loud noise followed by the engine stalling and not re-starting.

If the tensioners areloose, when you first start the engine you could hear a rattle as the slack in the chain is hitting the tensioners.

The valves will hit the pistons, needing a complete valve job at several thousand dollars.

Same thing happens if a dual chain breaks.

Metal

Any mechanic should be able to replace the chain and tensioners. It is not a dealer only repair.

>
Reply to
sdp1

And if you're really unlucky, those valves could punch holes in one or more of the pistons.

- Logic316

"Going to war without France is like going deer hunting without an accordion. You just leave a lot of useless noisy baggage behind." -- Jed Babbin

Reply to
Logic316

Punching holes in pistons is not likely. It's more likely that you will cut a hole in the oil pan with the broken timing chain and shear off the crankshaft sprocket woodrift key. So you have to pull the crankshaft as well as the heads to repair the engine. The crankshaft woodrift key slot will have to be welded. Ugly stuff. I should know because I broke a timing chain on a 617 Mercedes diesel engine.

Reply to
VCopelan

"...and when the chain breaks the timing will fall and down will come valve heads pistons and all.."

Eight out of ten times you just get four bent intake valves... occassionally more... once in a great while a valve head breaks off and damages both a piston and a cylinder wall, sometimes punching into the cooling jacket.

Bill Ditmire Ditmire Motorworks,Inc.

425 White Horse Pike Absecon,NJ 08201
formatting link
609-641-3392
Reply to
Bill Ditmire

--------------------------------

- When the timing chain breaks, your whole life flashes in front of your eyes. Loud bang, engine stops immediately, possible crack or hole in valve cover. Thousands of dollars to fix.

- There is a very distinctive chain slap noise if the tensioner is bad or the chain is stretched/worn excessively. It is different than lifter tick and may be present only at startup. The flopping around of the chain can cause it to jump a tooth on the sprocket or break a guide rail, then the interesting things happen. I believe the suggested replacement interval is 40K miles, 100K for the double row chain. As the chain wears, valve timing becomes less accurate. Lack of the chain slap noise does NOT mean you are safe with a single row chain.

- The chain, sprockets, and guide rails are metal, rail covers are plastic. A new single row chain can be had for $70 (but not at a dealer), and can be replaced by one person in a few hours, removing sparkplugs, fan, and RH valve cover only. An extra set of hands makes it a LOT easier. The idea is to not lose valve timing as you pull one chain out and feed the new in while turning the engine by hand. Replace the tensioner at the same time as cheap insurance.

- Some early 380 SLs had the conversion done at dealers, in a sort of stealth recall. If you have long skinny fingers you may be able to feel if the conversion has been done through the oil filler hole in the valve cover. Otherwise, use a dental-type mirror or pull the valve cover. You don't say what year you have, but you may be late enough to have a factory install. All the parts (chain, rails, gaskets and seals, sprockets, tensioner, etc.) for the conversion can be had in a kit for $700-$800 and the job is one long day or short weekend depending on what tools you need to run out to get and general skill level. Not difficult. Do be careful, as the block is alloy and it is easy to strip threads.

- Do the conversion, life is too short.

Mike "Silverbird" '82 380 SL 161K

--------------------------------

Reply to
Michael Davis

Heck, if Mercedes will do it for free, I'd like my 380SL with 37k miles done.

Reply to
Ptolemy

Here is what mercedes told me about the single timing chain a few years ago:

MERCEDES STATEMENT START: "...all we are saying is that it is impossible to predict timing chain failure. There are too many vairables (age, mileage, usage, driving conditions, etc.), and because of this we do not provide a listing, or recommended mileage for replacement. We now only provide a double-rolling chain because we used it on the new 6 and 8 cylinder engines after 1985. Because it is retrofittable for the previous engines, why supply both? It is simply an evolution of parts. We don't feel the single rolling chain is a "time bomb", it was a very effective design, and yes many have lasted (according to owner reports) in excess of 200,000 miles."

MERCEDES STATEMENT END

Reply to
Ptolemy

Lawyers wrote this, not engineers. The single row chains were an unmitigated disaster and he's right about not being able to predict failure - they can go in as few as 30K miles.

They only used them on US spec 380's for a couple of years.

Reply to
Richard Sexton

Whats the chances of getting Mercedes to foot the bill to convert to dual chain timing?

Reply to
Ptolemy

I think we could probably figure that one out for ourselves. Given that Mercedes never officially acknowledged there was any thing wrong with the single row timing chains, and given that there was never an

*official* recall for the 380 SL's so equipped, I doubt whether Mercedes would be too eager to establish a legal precedent by picking up the tab for anyone's conversion to a two row chain at this late date.

It might be possible to romance some enterprising attorney into championing your cause and filing a class action suit against Daimler Chrysler on behalf of all 380 SL owners who paid for their own conversion, but bear in mind that Jerkin Shrimp has lawyers too - lots of 'em. Personally, I think you might be better advised to fork over the $3K (or so) required for the conversion to your favorite independent, and sleep soundly knowing you did your share to help get our sagging economy back on its feet again. They're basically good long-lived cars, and sooner or later you'll have owned it long enough to see things swing back around your way again financially. Keep the faith...!!

Jerry Wolfram '78 450 SL - 211K miles

Ptolemy wrote:

Reply to
Jerry Wolfram

timing?

Reply to
Bill Ditmire

These days? Zero.

Reply to
Richard Sexton

Today there was a 'celebration day' at the local Mercedes dealer. I received a post card to bring my Mercedes in for a free inspection - this was a general mailing for all Mercedes and was really an attempt to get customers in the showroom. In any case, the post card said a Mercedes Rep was going to be there. Well, I took my 1983 380SL and asked about the famous single row timing chain issue and said that it was mentioned all over the Net. The Mercedes rep said that is was not a concern and not to be worried. Just keep the oil changed regularly and consider the single timing chain a 'maintence item' and at 75,000 miles just replace the chain. He said that it was mileage that is the issue not that my SL was 21 years old and 37,000 miles.

So, I got his card and told that all is OK. At the rate I drive my SL, it will be 40 years old before it needs the timing chain replaced.

Evidentually, there are some high mileage SL's out there with the single timing chain. Perhaps this issue about the single row timing chain is overblown. With this confidence that the Mercedes rep has given me, if it does fail, I will have to raise a ruckus and see what happens. Most likely with my luck, I'll just have to pay for the cost of a new engine. BTW, what would a replacement engine cost me?

Reply to
Ptolemy

Change it to a double row chain now, he lied or honestly did not know. Or you can just wait until it breaks and buy a new engine for about $5,000 US :-)

BTW, driv>

Reply to
Jeremy

keep the oil changed regularly and consider the single timing chain a 'maintence item' and at 75,000 miles just replace the chain.

Reply to
Bill Ditmire

Maybe you can buy a used or "rebuilt" engine for $5,000, but a new one might set you back more like $12,000.

Bill Ditmire Ditmire Motorworks,Inc.

425 White Horse Pike Absecon,NJ 08201
formatting link
609-641-3392
Reply to
Bill Ditmire

So what do people ususally do - is the car even worth putting in a new engine? Is it worth more as spare parts than fixing?

Reply to
380SL

Is there any data on the reliability of the single timing chain? How about reliability of the single timing chain versus the dual timing chain? What happens if one of the chains in a dual chain engine breaks or jumps off its guides?

Reply to
380SL

reliability of the single timing chain versus the dual timing chain? What happens if one of the chains in a dual chain engine breaks or jumps off its guides?

Reply to
Bill Ditmire

MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.