Right now I'm trying to find a later model cam. It would appear from my MB manual that one stamped with a #49 is what I'm looking for. I've spent all week trying to find one and I'm down to one last guy who's checking, so if anyone has a lead.....?

BTW, From my MB manual it would appear the the correct cam for my engine would be #42 which states, "Camshaft tin-coated, cam 1 mm wider, standard as of 10/86."

Does anyone know what is "1 mm wider" the journals or the lobes or both?

I'll plastiguage the journal clearances when I go to take it apart again, anyone know what the spec is on cam journal clearances?

I purchased the last cam from a guy that sells on e-bay and everything came jumbled in a box, there was no way to match cam to rocker...so that wasn't done on last assembly. I'm assuming that will be the case when I get the next one too.

Lastly...

I'm concerned about the Zinc problem though. I've got a '76 pickup and a '67 TR4a that I've been running the same oil in. I wonder what those cams look like?

Has anyone tried Motorhead Z-boost?

http://www.motorheadoil.com/

Thanks

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Bob Kopicki
Massillon OH
'97 VW Cabrio (POS)
'93 Miata
'87 300e
'76 GMC C-15
'67 TR-4a

How often do you change your oil and filter? Hard to say for sure, but judging from the way your valve springs look, not often enough.

Does this engine have self adjusting (hydraulic) valves? It's conceivable that there is not enough valve lash or that there is too much pressure while the cam is on the base circle, not letting the oil flood the contact zone.

Mismatching cam lobes and rockers that are used is sure to cause much more rapid wear.

I wouldn't worry about the TR-4. It has tappets that rotate in their bores slightly as they ride on the cam. The contact isn't pure sliding the way it is in the MB, and the wear is distributed around the surface of the tappet more.

__________________
1987 W201 190D

I second that, looks like there's some sludge going on in there....

__________________
-diesel is not just a fuel, its a way of life-
'15 GLK250 Bluetec 118k - mine - (OC-123,800)
'17 Metris(VITO!) - 37k - wifes (OC-41k)
'09 Sprinter 3500 Winnebago View - 62k (OC - 67k)
'13 ML350 Bluetec - 95k - dad's (OC-98k)
'01 SL500 - 103k(km) - dad's (OC-110,000km)
'16 E400 4matic Sedan - 148k - Brothers (OC-155k)

That's pretty funny about sludge and frequency of oil changes. As I said in the initial post, I don't know how many miles are on this car, but it appears that it had frequent oil changes since there was NO sludge when I originally opened it up 3 years ago. The discoloration is from conventional oils being used prior to my use of synthetics.

I've never opened a high mileage engine that has used only conventional oils and not seen discoloration.

It is impossible for synthetics to produce sludge in reciprocating engines since the temps necessary for its formation are not present where the oil circulates. Therefore, if there was NO sludge in the engine when I opened it up 3 years ago and I've used nothing but synthetic oils since, there is NO sludge in the head now.

To answer the question, I change the oil and filter every 6000 miles (which I'm told is probably too often for synthetics).

That said, I suspect my wear is from:
1. Lack of zinc in Mobil 1 making the expense of synthetic oil in older engines a waste of money.
2. Worn bearing journals in the head.
3. Poor metallurgy in the cam/rockers

I can assure this forum that the frequency of oil changes is NOT the problem here.

I've included another picture that shows the bottom of the head where it can be clearly seen.

Attached Thumbnails

 

__________________
Bob Kopicki
Massillon OH
'97 VW Cabrio (POS)
'93 Miata
'87 300e
'76 GMC C-15
'67 TR-4a

Mismatched parts can definitely cause this. If you can't get them lined up, replace one side or the other with new (new camshaft or all new lifters). Then do a proper camshaft break-in.

If you're going to use used parts, you would be better off going to a wrecking yard and pulling the cam yourself, so you can index the parts.

It is a problem with above average spring pressure and flat tappet cams. I run flat appet cams in my three 750 hp blown 572's in Plain Vanilla. A few years ago a wiped all three cams, almost all at once! WTF! That's when I found out about the reduction of ZDDP. Then I started using Rotella T. But they've now reduced the ZDDP in it. So now I use Rotella T and use General Motors Engine Oil Supplement, the old stuff. I buy it on ebay whenever I find any.

The new stuff is ok, but you have to use a bit more. You need to become budies with the local GM dealership so you can get any discount you can get.

Stay away from ebay - those eos containers are mine....

But if you are not running higher spring pressures, which I do not believe you are, I think you'll still be ok with Rotella T, DELVAC, Delo 400, etc. Check their websitres to see which one has the highest ZDDP and use that one.

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Thank You!
Fred
2009 ML350
2004 SL600
2004 SL500
1996 SL600
2002 SLK32
2005 CLK320 cabrio
2003 ML350
1997 C280 Sport

Ten bucks an ounce! Yikes. GM EOS at 20 bucks for 8 ounces is a bargain! And then go buy a case of eos and some once bottles. Sell them for 5 bucks each to pay for the EOS you use.

Go to your local GM dealer and buy some EOS.

As for cams and lifters - I would not ever mismatch them after they've been run.

Find and engine that has a good cam and lifters, and swap the entire set. And keep the lifter matched to the lobe.

Do Mercedes lifters use rotators? If so, maybe the lifter had a bad rotator on that wiped lobe.

Or, is the valve sticking in the guide at that wiped lobe? Or some type of binding going on there? Something's gotta give when that happens.

I highly doubt it has anything to do with metallurgy. If it were metallurgy, I suspect the damage would be almost immediate.

__________________
Thank You!
Fred
2009 ML350
2004 SL600
2004 SL500
1996 SL600
2002 SLK32
2005 CLK320 cabrio
2003 ML350
1997 C280 Sport