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  #1  
Old 09-02-2003, 04:44 AM
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Location: Sydney, Australia
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Valve cover woes

With concours time now very close, I thought I would remove the valve cover (cylinder head cover, rocker cover) from my 190E and bead blast it to remove the remaining flaking black coating and repaint it. While it is off I can also fit new hydraulic valve lash compensators (lifters) to address the intermittent ticking during warm-up. A new gasket or seal would also address the oil leak from under the cover.

Great plan but it got de-railed. The cover leaks not because the gasket is faulty, but because the cover is distorted. OK I think, let's price a new cover. None in stock in Australia and price is over $700 AUD. Forget that plan. Let's chase a used one. Problem is they are all distorted like mine. Looks like I'll be re-painting mine and refitting it with a new gasket with some sealant. But that's not all. The oil separator for the breather under the cover is plastic. Heat has taken its toll and the plastic is all cracked and falling apart. Lets price the oil separator. That's available interstate at about $70 AUD but supposedly does not suit my car. They will get it in for me anyway but I suspect that the oil separator under my cover is considered part of the cover and not available separately. I won't know until I see the one they are getting for me. If that doesn't fit I guess I will have to get very creative and fabricate my own from sheet metal.

Why do they spoil these otherwise well engineered cars with such poor materials that distort or crumble like dry dog-do when exposed to heat and age. Have others had similar problems with their M102 (or M103 or M104) valve covers?
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107.023: 350SLC, 3-speed auto, icon gold, parchment MBtex (sold 2012 after 29 years ownership).
107.026: 500SLC, 4-speed auto, thistle green, green velour.
124.090: 300TE, 4-speed auto, arctic white, cream-beige MBtex.
201.028: 190E 2.3 Sportline, 5-speed manual, arctic white, blue leather.
201.028: 190E 2.3, 4-speed auto, blue-black, grey MBtex.
201.034: 190E 2.3-16, 5-speed manual, blue-black, black leather.
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  #2  
Old 09-02-2003, 10:05 AM
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Regarding the warped valve cover: This is also a problem on 126 V8s and though I have not personally done it, someone else on this forum took his and had it machined. So you may want to take your valve cover to a machine shop and they could just mill off what they need around the bottom to make it true. I'm afraid the sealant would be more of a band-aid fix.
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  #3  
Old 09-02-2003, 10:41 AM
moedip
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Hi There - I'm the one who had to get his 560sel valve cover milled. Over a year now and still perfect. The reason they warp is NOT poor quality - it's over torquing the bolts that hold it down. Any good machine shop will be able to mill the bottom edge for you. Mine had to have 7 thou milled off to level it. New crush washers and a torque wrench set to 4 foot lbs - no more problem. Yes I was quoted $600 for a new cover but the Mercedes Dealership told me that they could send it out to get milled for about $150. I went to a shop that mills valve covers for racing engines - apparently they are notorious for warpage from the extreme conditions they are subjected to. The shop charged me $70 CDN - well worth it. If the 190's are doing the same thing - buy up all the warped covers you can - mill them and re-sell them for 50% of new - every one wins!! Just - remember - DO NOT OVER-TORQUE THE BOLTS!!!!
Signed - learned the hard way.
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  #4  
Old 09-02-2003, 08:39 PM
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Location: Sydney, Australia
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That's interesting you mention problems with the late M117 (and presumably late M116) valve covers. Are they aluminium like the early engines or magnesium like the later ones? From memory, they are painted or coated suggesting magnesium. Do they suffer the same problem of the coating blistering and peeling like with the M102 & M103? The early M116 in my 350SLC has valve covers in aluminium without any coating. After 30 years they still look good and seal just fine. You mention having 7 thou taken off to make yours flat again. The cover from my 190E looks like it would need 70 thou off to make it flat again! The distortion cannot be caused by over-torquing the nuts in this case since the cover has spacers around the studs which bottom out, giving the correct crush on the gasket. Machining is not an easy option either since the cover has a groove to locate the gasket. The groove would need to be machined as well as the face. The spacers would also need to be machined a similar amount to allow the correct gasket crush.
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107.023: 350SLC, 3-speed auto, icon gold, parchment MBtex (sold 2012 after 29 years ownership).
107.026: 500SLC, 4-speed auto, thistle green, green velour.
124.090: 300TE, 4-speed auto, arctic white, cream-beige MBtex.
201.028: 190E 2.3 Sportline, 5-speed manual, arctic white, blue leather.
201.028: 190E 2.3, 4-speed auto, blue-black, grey MBtex.
201.034: 190E 2.3-16, 5-speed manual, blue-black, black leather.
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  #5  
Old 09-03-2003, 05:58 AM
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Quote:
From memory, they are painted or coated suggesting magnesium.
Im 99.99% sure they are not magnesium. Too expensive and difficult a metal to use on such a routine part.

I believe they are aluminium that is powder coated. Where corrosion gets under the powder coating, the aluminium turns to a powdery oxide that could suggest that its magnesium, but it's not. Your SLC covers will be anodised.

I've sold my 190E so can't look at the cover. The spacer system you describe should surely stop warping of 70thou. I'm not arguing with you, it just doesn't make sense the way you put it!
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  #6  
Old 09-03-2003, 01:56 PM
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On the 560 I know that the older ones are black and the later ones plain aluminum. Mine are black ('89), and at a junkyard while searching for other parts I found a 1991 560 SEL with aluminum covers. I suspect the black ones were simply painted.

Torquing is EXTREMELY important on these, by the way. I bought a 1/4" torque wrench just for these covers.
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  #7  
Old 09-03-2003, 08:32 PM
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Quote:
Originally posted by neileg
Im 99.99% sure they are not magnesium. Too expensive and difficult a metal to use on such a routine part.

I believe they are aluminium that is powder coated. Where corrosion gets under the powder coating, the aluminium turns to a powdery oxide that could suggest that its magnesium, but it's not. Your SLC covers will be anodised.

I've sold my 190E so can't look at the cover. The spacer system you describe should surely stop warping of 70thou. I'm not arguing with you, it just doesn't make sense the way you put it!
The MB North America M102 shop manual definitely states that the cover is magnesium. Some earlier 190Es got a plastic cover that was even worse. They recommend replacing the plastic cover with the metal one. The extremely light weight of the cover also tends to confirm a magnesium alloy. At the price of a replacement I decided against trying to see how well it burns to confirm whether it is magnesium! The cover on the M103 in our 300TE appears similar, although it is still in reasonably good condition with only a couple of blisters in the coating. I maybe incorrectly assumed the black finished covers on the engines of mid '80 onwards all used magnesium. These covers have areas with a rough finish under the black coating, unlike the all-over smooth finish of those on the MB engines of the '60s and '70s.

Checking my M102 valve cover with a straight edge confirms up to about 2mm (0.079") variation along the gasket face on the side with the scallops for the spark plugs. The sections without the mounting holes sit that much higher than those with. The opposite (inlet) side which should be straight also has an obvious bow in the middle. On checking, it was found second hand covers were in no better shape than mine.
__________________
107.023: 350SLC, 3-speed auto, icon gold, parchment MBtex (sold 2012 after 29 years ownership).
107.026: 500SLC, 4-speed auto, thistle green, green velour.
124.090: 300TE, 4-speed auto, arctic white, cream-beige MBtex.
201.028: 190E 2.3 Sportline, 5-speed manual, arctic white, blue leather.
201.028: 190E 2.3, 4-speed auto, blue-black, grey MBtex.
201.034: 190E 2.3-16, 5-speed manual, blue-black, black leather.
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  #8  
Old 09-04-2003, 06:50 AM
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I stand corrected! Sorry for the duff opinion.

I still find it strange that MB would use magnesium. It surely can't be for weight saving?
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  #9  
Old 09-15-2003, 11:10 PM
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With the concours out of the way now I have time to report the outcome of the valve cover problem. I decided to stay with my cover which I bead blasted and repainted with engine enamel (along with the air filter cover). The oil separator the dealer got in for me did not fit my valve cover. It was a metal one for earlier M102 engines. The plastic oil separator in my valve cover is considered part of the valve cover and is not available as a separate part. I therefore got busy and fabricated my own copy from sheet steel. It seems to work fine and at least it won't crack like the plastic one. As for the warped valve cover, I refitted it with a new gasket and black gasket silicone in the groove to hopefully take up any gap. So far so good.

While the valve cover was off, I fitted 8 new hydraulic valve lifters (lash compensators) which were inexpensive. This was the easy part of the whole job and silenced the previously intermittent ticking during warm-up.

I also fitted a new radiator as it had been leaking since replacing the leaking coolant expansion reservoir. Unfortunately, this has highlighted the leak at the heater control valve which I will now have to replace. I chose to fit an after-market radiator for an auto transmission 190E since at around $350 AUD it was much less expensive than the $900 plus for an OEM radiator for my manual transmission 190E. No after-market radiators were available here in a manual version. The only difference of course, is the transmission cooler connections on the auto version. I capped these purely for appearance sake.

All this delayed my concours preparation so come last Sunday, the 190E was not as clean as I would have liked, although I still entered it (and the 300TE) for judging. Fortunately, the 300TE was fairly well prepared and ended up taking a class win in what turned out to be the biggest class on the day with some other very well prepared cars. Both of ours were in the same class anyway with the class including all W201 and W124 in addition to pre 1996 R129, W140 and W202. All the hard work paid off and the 190E is getting closer to being fault free.
__________________
107.023: 350SLC, 3-speed auto, icon gold, parchment MBtex (sold 2012 after 29 years ownership).
107.026: 500SLC, 4-speed auto, thistle green, green velour.
124.090: 300TE, 4-speed auto, arctic white, cream-beige MBtex.
201.028: 190E 2.3 Sportline, 5-speed manual, arctic white, blue leather.
201.028: 190E 2.3, 4-speed auto, blue-black, grey MBtex.
201.034: 190E 2.3-16, 5-speed manual, blue-black, black leather.
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  #10  
Old 09-16-2003, 03:09 AM
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Greg

Have you posted any pcitures of your cars?
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Last edited by haasman; 09-16-2003 at 03:56 AM.
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  #11  
Old 09-16-2003, 03:43 AM
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Quote:
Originally posted by haasman
Greg

Haave you posted any pcitures of your cars?
Back in the "Let's all post pics of our Benzs" thread starting at
http://www.peachparts.com/shopforum/tech-help/29311-lets-all-post-pic-our-benz-s-post434549.html#post434549
there are some pics of our 3 Benzes. My much loved and much used 350SLC is not fit to be seen at a concours. My 190E Sportline is pretty tidy but not real concours material. Our 300TE is a real gem, especially for a daily driver. I will post some pics from Sunday's concours when I get them processed and scan them (no, I don't have a digital camera yet).
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107.023: 350SLC, 3-speed auto, icon gold, parchment MBtex (sold 2012 after 29 years ownership).
107.026: 500SLC, 4-speed auto, thistle green, green velour.
124.090: 300TE, 4-speed auto, arctic white, cream-beige MBtex.
201.028: 190E 2.3 Sportline, 5-speed manual, arctic white, blue leather.
201.028: 190E 2.3, 4-speed auto, blue-black, grey MBtex.
201.034: 190E 2.3-16, 5-speed manual, blue-black, black leather.
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  #12  
Old 09-16-2003, 04:43 PM
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Greg

Quote:
While the valve cover was off, I fitted 8 new hydraulic valve lifters (lash compensators) which were inexpensive. This was the easy part of the whole job and silenced the previously intermittent ticking during warm-up.
Do you have a procedure for that, plus any tips - I guess it must be similar for a 4 cyl 230 TE!

Cheers
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230 TE (W124) 1989 with 153,000 miles on the clock - hoping for at least another 100K
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  #13  
Old 09-16-2003, 08:52 PM
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Quote:
Originally posted by NormanB
Greg



Do you have a procedure for that, plus any tips - I guess it must be similar for a 4 cyl 230 TE!

Cheers
Norman,

I'm sure the procedure would apply to all M102 engines. It almost takes less time to do than reading about it in the workshop manual.
1. Remove valve cover (and whatever else eg. air filter that is required to remove valve cover).
2. Remove 2 bolts that secure oil spray pipe and remove pipe.
3. Rocker arms are grouped in pairs for each cylinder. For each pair, rotate engine (at crankshaft pully in correct direction only) such that rockers are on the back of the cam lobes (ie. valve springs not compressed).
4. Remove bolts for that pair of rocker supports (camshaft bearing).
5. Carefully lift rockers with support/camshaft bearings taking care not to lose ball cups from top of valve stems. These should remain with their original valve.
6. Hydraulic lash compensators (lifters) are an easy press fit into (valve end) of rocker arm. Press these out of rocker arm with soft metal rod (brass or aluminium).
7. Fill reservoir on new lash compensators with engine oil and press into rocker arms taking care that discs that sit on top are re-installed correctly (ie. same way up as when removed).
8. Re-install rocker assembly taking care that ball cups are seated correctly on top of valve stems. Torque bolts as per manual (20Nm from memory)
9. Repeat for remaining pairs of rockers.
10. Re-install oil spray pipe and valve cover.

I'm sure it almost took less time to do than to type. The only comment I should make is that the hydraulic compensators can be noisy for two reasons. One is that they are worn out (as mine were). The second is that due to valve work (eg. regrind) or valve or valve seat wear they are out of their possible range of "adjustment". If this is the case, different thickness disks are available that fit on top of the lash compensators. The MB M102 shop manual outlines the procedure to measure for this situation. I did not consider this to be the problem in my case as the lifters were only intermittently noisy during warm-up. New lifters have solved the problem. The shop manual also describes the procedure for identifying which lifters are at fault (leaking down). I did not bother with this since at around $24 AUD each for OEM or $16 AUD each after-market, the lifters were inexpensive. For this reason I chose to replace all eight.

Hope this is helpful to you or any other M102 owners.

Greg
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107.023: 350SLC, 3-speed auto, icon gold, parchment MBtex (sold 2012 after 29 years ownership).
107.026: 500SLC, 4-speed auto, thistle green, green velour.
124.090: 300TE, 4-speed auto, arctic white, cream-beige MBtex.
201.028: 190E 2.3 Sportline, 5-speed manual, arctic white, blue leather.
201.028: 190E 2.3, 4-speed auto, blue-black, grey MBtex.
201.034: 190E 2.3-16, 5-speed manual, blue-black, black leather.
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  #14  
Old 09-17-2003, 03:28 AM
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Thanks Greg.

That is excellent.
Mine is an occassional ticker so I will do that job idc.

Cheers
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230 TE (W124) 1989 with 153,000 miles on the clock - hoping for at least another 100K
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