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1983 380SL, 2000 S430, 1991 420SEL (retired) - RHD
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Discussion Starter #1
I just received 2 new rockers to replace the two I mixed up when bagging during my TC/tensioner/guides change saga and after looking at the new ones I think the old ones could be worn out. The new ones had the coating completely covering the small (valve) side.
I think I may need 14 more? The car has done about 90,000 miles (to my knowledge) but mostly short runs around town.
 

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'85 380SL (155Kmiles), '82 240D stick, '80 300SD, '77 240D, '89 BMW 535i, 3 VW Diesels, 2 Triumphs
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You talkin' to ME?

This may start another pissin' contest, but IMO, no. I would use them. It's a subjective thing. If you have money to burn, replace them all.

The wear on the cam side looks just fine to me. The wear on the valve side is also fine, but that's from hammering on the valve rather than having the cam sliding past it. The compensator should be able to take care of that. If your cams aren't noisy I would leave them alone and keep applying zinc. If they are noisy or worn, it's time to start replacing parts. If it's time to replace parts, probably need to replace everything topside.
 

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Premium Member
1983 380SL, 2000 S430, 1991 420SEL (retired) - RHD
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Discussion Starter #3
Well that's good news- I could do with a little. Money to burn I DONT have.I hope you win the pissin' contest!
 

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Premium Member
1986 560SL with M120 V12 Engine, 1988 560SL Stock
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Its hard to tell from the picture it looks a little rough but may be OK. Here is a few pictures of a set I recently sold on Ebay that I thought was in very good condition. The right side rockers are all fairly new as there was evidence of a new right cam shaft.
 

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1983 380SL, 2000 S430, 1991 420SEL (retired) - RHD
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Discussion Starter #5
The lobe side on mine looks the same as yours (bad pic of mine) nice and smooth with no scratches or grooves, but you can see the bright finish on the valve side on mine is very short- just a small rectangle of bright ungrooved finish.I noticed the 2 new rockers I just bought had coating on the whole face of the small side- just like the large side (and yours in the pics).All the other rockers were the same as the 2 in my pics.Now I'm a bit uncertain.
 

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1986 560SL with M120 V12 Engine, 1988 560SL Stock
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The lobe side on mine looks the same as yours (bad pic of mine) nice and smooth with no scratches or grooves, but you can see the bright finish on the valve side on mine is very short- just a small rectangle of bright ungrooved finish.I noticed the 2 new rockers I just bought had coating on the whole face of the small side- just like the large side (and yours in the pics).All the other rockers were the same as the 2 in my pics.Now I'm a bit uncertain.
What looks like a coating in the last pic I sent on the left 3 rockers is just a camera angle. The were all shinny. You should be OK as long as the lobe side has a continuous curve in the contact area and is smooth. Usually when they are bad, there the can will wear a line across it. Don't worry about the valve side so much as there is not too much doing on there and the rocker and pad are cheep and easy to replace if something goes wrong on that end.

I say go for it.
 

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1983 380SL, 2000 S430, 1991 420SEL (retired) - RHD
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Discussion Starter #7
Worn rockers

Thanks mate. I have the removal tool so it is easy to replace them. I'll put it back together- I've spent enough on the project already.
 

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1978 450SL--117K
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If it doesn't look like your new ones, it's shot. I cannot see enough of Ron's left set of rockers for sure, but if that is what it looks like in the pic from here, they are shot. go look at my rockers, those are nice, clean pics. Those rockers were shot--and only four of them showed signs of wear through. Not all of them, just four.

but you'll know for sure when your compression drops off......Therling posted the response from MBCA. It confirmed what I had been told and what I posted in your thread.

You could always take them to a dealer and get another opinion, you know.
 

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'85 380SL (155Kmiles), '82 240D stick, '80 300SD, '77 240D, '89 BMW 535i, 3 VW Diesels, 2 Triumphs
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but you'll know for sure when your compression drops off.
I mean this with the utmost of respect, but bah humbug. As long as the cam that that rocker goes to looks as good as that rocker, his compression is not going anywhere as a result of the the top end for ten and tens of thousands of miles. Even if the cam and valve were completely worn radically how would that affect compression? Compression is just the sealing of the valve and rings- this has little to do with that.
 

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I mean this with the utmost of respect, but bah humbug. As long as the cam that that rocker goes to looks as good as that rocker, his compression is not going anywhere as a result of the the top end for ten and tens of thousands of miles. Even if the cam and valve were completely worn radically how would that affect compression? Compression is just the sealing of the valve and rings- this has little to do with that.
Short answer is, go look at a moving animation of an internal combustion engine. How do you expect the cam lobes to properly open and close the valves if they are worn down? Just how much tolerance do you think there is?

For one thing, they don't look that good--the rockers. For another, Aussie clearly states that the new ones look a whole lot better. If they were in good shape, there would be no noticeable difference. It was already debated here as to whether or not the rockers have a coating--they do, it's nickel. The cam lobes will wear out very fast if the nickel coating wears off. once the cam lobes wear down, they will no longer be able to operate correctly, i.e., they will not open and close the valves according to specifications. This will affect both compression and vacuum. It will cause a drop in horse power, fuel efficiency and most likely lead to burned valves. This can all happen very rapidly under the right circumstances.

As mush as I respect Ron, indeed, all of the "old timers" (long term members) on this board, I disagree mightily with the idea that it won't harm anything that isn't cheap and easily replaceable. The cams are not cheap, for one, but on another note the idea goes against my philosophy of maintenance. To wit, the moving parts of an engine are designed to work within very specific tolerances. When a part wears beyond those tolerances, it affects negatively everything that it comes into contact with. Likewise, those parts begin and will affect negatively every part they come into contact with. Since we cannot ever really know how well the car was maintained, as such, I always assume the worst and am pleasantly surprised if it turns out otherwise.

If the timing chain is meant to go 100,000 miles, give or take 10%, then it stands to reason that a person should remove any parts with which it operates which will wear out before that time--even if that time period is 40 to 50,000 miles. Which, as we have learned from MBCA, via Therling, is not the case. The rockers are not lasting as long as they were intended and have become, in their opinion, a maintenance item, ie., get rid of them at the time the chain is replaced if there is any noticeable wear on any of the rockers--because the others will soon follow.

All I can say with regard to the one car that I have had this done to is is that it pulls 22" of vacuum--while idling, does yours? Its compression is factory spec. It hauls ass--in no uncertain terms. It benefited mightily from this. But, and this is just as important, it is a strong indication that the car was always taken car of properly. Had it not had proper maintenance , it would not have been so clean inside (sludge would have developed) and the compression/vacuum would not be so strong. I point this out because the last time this came up, I was told my car's rockers were indication that something was very wrong with the engine--its vacuum and compression say otherwise to anyone who understand what they represent. It also came out, via Therling, that this is indeed the case--that the rockers, for whatever reason, are not lasting as long as they used to. Oil was considered to be the culprit--the content of the oil has changed over the last 30 years as have the alloys that engines are made of. The changes in some oil additives negatively affect older engines.

I rest my case.
 

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'85 380SL (155Kmiles), '82 240D stick, '80 300SD, '77 240D, '89 BMW 535i, 3 VW Diesels, 2 Triumphs
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What Therling said was....

Here's an opinion about rocker arm wear from one of the Tech folks over at MBCA's website:

"Well, prior to the newest formulations/additive packages, or rather what oils are for the most part lacking, I'd have said don't worry about it..rocker failure is fairly uncommon on a well maintained engine..and not something I would do as part of a preventative maintenance package..

That said, in the past two years I have replaced More rockers then in the previous 8. Hardening blown through in spectacular fashion. The worst cases of course require new cams as well.

These days removing the All the rockers during the timing chain/rail replacement is a given.

My Strong piece of advice, make SURE the oil you are using is an older formulation that has plenty of anti wear/extreme pressure lubricants. Buying and adding said additives to what ever oil you use does not appear to work either, a quick visit to the Muscle car forums will show as much."

Yes, I know I'm possibly kicking the dreaded "what kind of oil should I use" hornet's nest, but this opinion does provide some support the case that rocker arm wear is more of a problem than it used to be.

Tom H.
and you said...

It also came out, via Therling, that this is indeed the case--that the rockers, for whatever reason, are not lasting as long as they used to. Oil was considered to be the culprit--the content of the oil has changed over the last 30 years as have the alloys that engines are made of. The changes in some oil additives negatively affect older engines.
I agree with both statements, but I haven't seen anything posted by aussiemerc that indicates that his rockers or cams are wearing unusually, ticking, etc. I have taken quite a number of valve covers off junkyard M116 engines in the last 2 years ( trying to find a set of cams, just for the eventual contingency , and to get a supply of shims and compensators) and I don't like what I see. It is very true that if you fall for the latest marketing hype by the oil companies and get the latest and most popular oil, without paying attention to its ZDDP and additive package as it relates to MB 116/7 engines, you are going to eventually be in a world of hurt. He's not there, IMO, and unless he switches oil or they change the formula, I don't see the need to do anything.
 

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Another thing about timing chains in general. The older guys here know, as I do, that for the most part during the time period these cars were built, all timing chains on all cars pretty much had to be replaced around 100,000 miles or the car would go to far out of time, or worse, the chain would jump a tooth. This was not such a big deal on American cars because they were push rod engines, not OHC engines like these. The timing chains were easy to get to and easy to replace. But, American cars typically needed, at minimum, a top engine refresh (new rockers, push rods, valve job, etc.) by this time. a very large number required complete overhauls. These cars, without a doubt, are much more durable, but nothing lasts forever and there is a price to be paid. In this case, it is the timing chain, which, when replaced properly, is a top end refesh for these cars. It therefore makes perfect sense to me that, no matter what the intent was at the time of design and build of the engine, that they may need more than just the chain and guides replaced ( a pain in itself) to accomplish this. But this means that the car, if properly maintained, will go another 100,000 miles. Which, in the case of these cars, means they will most likely have become a whole lot rarer, given that a lot of people are not going to spend the time and money to keep them in proper shape. Doing so, will make your car more valuable over time, which is the essence of car collecting. Smart car collecting is not buying the car at the top of the price curve--unless you are filthy rich, it is spotting a possible collectible early on and snapping it up, setting it right and, hanging on to it.

I have come, in some sense, to view these cars as somewhat akin to owning and maintaining a fine old wooden boat. They are not for the weak of heart nor the lazy. These things, just like a Chris Craft or Porsche or even Ferrari, need a lot of love and care.

The guys that have been on this site for a long time are people that understand this and like it. Those that grow weary of their cars are those who do not share the same love and affection for them. They sell them before too long and move on to something easier and cheaper to take care of. I have a lot of respect for these guys and in fact, have spent the last two years mostly reading everything they have written and asking them questions, so as to learn as much as possible. I guess what I am saying here is that if you learn anything from this site, it is that these cars need work--often lots of it, depending on who owned it in the past and how well they took care of it. It does no good to do things in half assed way unless you are a used car salesman looking to turn a quick buck.
 

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What Therling said was....



and you said...



I agree with both statements, but I haven't seen anything posted by aussiemerc that indicates that his rockers or cams are wearing unusually, ticking, etc. I have taken quite a number of valve covers off junkyard M116 engines in the last 2 years ( trying to find a set of cams, just for the eventual contingency , and to get a supply of shims and compensators) and I don't like what I see. It is very true that if you fall for the latest marketing hype by the oil companies and get the latest and most popular oil, without paying attention to its ZDDP and additive package as it relates to MB 116/7 engines, you are going to eventually be in a world of hurt. He's not there, IMO, and unless he switches oil or they change the formula, I don't see the need to do anything.
His rocker shows signs of having the nickel worn through, it is just a question of time before they go completely. The rockers are 20.00 each from online suppliers. It is not worth the price of new cam shafts to forgo them. None of us have any idea what the previous owner used for oil. We also, unless the car records show it was only maintained by a MB dealer and that the oil changes occurred every 3,000 miles or so, no idea how well they maintained the car. No one is going to admit to having let the car go 10,000 miles on an oil change when they are selling it. But back to Aussie. The pic shows the wear as I was shown it at the time I had the 560 replaced. If it were me, I would sigh, order the parts and be patient about it--no matter how exasperating.
 

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1986 560SL: '84 500SL: '84 280SL 5 speed: other 107s
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I doubt you can buy them for $20.00 US each in Australia.
 

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1983 380SL, 2000 S430, 1991 420SEL (retired) - RHD
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Discussion Starter #15
Worn rockers

A little history. I've owned the car 17 years and 33,000 miles. The oil has been changed every 6,000 miles. It's now done 90,000 miles.Tough mileage though- all short trips.

The timing chain, tensioner and guides were changed aged 14 in 1997 (60,000 miles on the odo)) because the engine blew a hole (without any warning) through the left valve cover. Several bent valves (front left cyl) and all the valve guides were replaced as part of the head reno of both heads. No rockers or cams were replaced.
I decided to change the tensioner etc after hearing a bad rattle - once was enough! especially considering the 15 years since the blow up.BTW my engine didn't tick at all.When I took off the valve covers the chain was VERY loose (subsequently discovered Febi tensioner installed).

In my bumbling efforts at timing chain/tensioner/guides replacement (see my continuing thread I now refer to as Quo Vadis) I managed to jam the chain so I then had to remove all the rockers. At the time they didn't look bad but I had no comparison point. Further bumbling meant I bought 2 new rockers and hence the comparison.

Back to the discussion at hand. None of the rockers were gouged or scratched but you can see the jagged mark at the edge of the coating on the larger face.My pic suggests there is wear on 1/3 of the area of the large face but the condition of that face is constant- the camera just shows a shadow.

Notwithstanding, by comparison I'd now say they they are well worn.Rowdie's right re the cost but I don't want to buy new camshafts so......wait for the next episode.
 

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1983 380SL, 2000 S430, 1991 420SEL (retired) - RHD
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Discussion Starter #16
Thanks a lot guys

Thank you to everyone for the very interesting (although costly) input.
 

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'85 380SL (155Kmiles), '82 240D stick, '80 300SD, '77 240D, '89 BMW 535i, 3 VW Diesels, 2 Triumphs
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If you change some or all of them, are you going to follow the SOP for breaking in new cams? (zinc break-in assembly lube, running engine 20 minutes at moderate speed)
 

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Premium Member
1983 380SL, 2000 S430, 1991 420SEL (retired) - RHD
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Discussion Starter #18
Break in of new rockers

If you change some or all of them, are you going to follow the SOP for breaking in new cams? (zinc break-in assembly lube, running engine 20 minutes at moderate speed)
You're way ahead of me RS. Yes, I do use assembly lube and thanks for the heads up re 20 min warm up.I'll be overjoyed if it runs!
 
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