The Machinist

The good news is that my engine S/N matches the VIN numbers, and my head bolts are the updated ones.

The bad news is that my cams are starting to show some wear at 69kmi




Drivers side intake cam.


This is the worst lobe, but is very similar to the others.

The profile is still 98% there, but there is pitting evident which means that the cam has worn through the hard face. This is where the MoS2 will help. The platelets will fill those pits to some degree and add some lubricity.

I guess I’ll be putting cams in in the next 10k or so. ****.

The Machinist

On another note, this engine has some incredible compression. I have a 24” ratchet on the crank pulley and it is surprisingly difficult to turn over.

Jasonoff

The fact it's worn across the whole face would be concerning to me. It may suggest the lifter bucket has stopped rotating.

roadtalontsi

that's nothing. You've got plenty of life on those. They always look like that. It's a race engine. They designed the top end to be easily serviceable for a reason. 6.2L v8 turning 8krpm, something has got to give. And i still need to get you a freakin camshaft adjuster!

The Machinist

Yes you do! (Taps foot impatiently.....)

I have started looking at what the internet has for camshafts out there. I found one company with a tragic name, “WebCams” willing to hard face weld and regrind for eleven or twelve hundred bucks a set. Going to ask for details....

Also going to reach out to schrick to see if they’ve got anything. They’ve got cams for my BBK Audi V8 listed for 3-400 euro each. That’s for new cams with DLC coating. Maybe they can grind something for us too.

Makes me wish my small cylindrical grinder at work had an indexable work spindle, I’d grind them myself.

The Machinist

Concerns me too, I did my best to look for wear on the lifters, and couldn’t see anything chowdered up. I should have stuck my plastic face pry bar in there to depress the lifter from the cam lobe to look underneath a bit better but didn’t think of that until I had it all closed up.


Another side note, the Accusump will need to go in the trunk. There is literally nowhere under the hood where it will fit. I thought I got lucky with the cavernous space above the ECU, but the accumulator is about a half inch too long. And that’s the first time I’ve ever had that problem. (That was a dick joke)


Looks like I have to shell out for 20’ of -8 line from earls.


Between my VW needing a $2000 clutch job and my Mercedes being a Mercedes, this is shaping up to be an expensive year.

I guess I had better get back out on the street corner.

BLKROKT

What about placing the Accusump low in front of the radiator or on top of the power steering cooler to save some line and give you better response? Depending on which one you have, I’ve seen people mount the smaller 1-2qt ones vertically - there are a few spots, maybe drivers side around where the washer fluid reservoir is (or just remove that) or in the drivers side bumper opening near the smog pump and horns. Other option is the transmission tunnel, not sure if it’ll fit but there are a ton of openings and mounting points back there just behind where the driveshaft connects to the trans.

The Machinist

Mines a 2qt. Do (the ubiquitous) we think in front of the radiator will block too much airflow? Pretty sure it would fit there. Would need directions to a procedure for front bumper removal to be efficient.
I’m still learning the Mercedes design “language.” All cars have their own. For example all VAG products have essentially the same type of construction. If you’ve worked on one Audi, the rest make sense.

Most GM products are built like 4th grade Erector set science fair project.

My first impressions with this car are that it is vastly less complex than any Audi. For example, I didn’t need to grow a second elbow and dislocate my shoulder to remove the valve cover like I did on the S4.

I was fishing around the passenger side of the Mercedes for vertical mounting, but the oil cooler is in the way.

Is there any room in the fender between the wheel and the front doors if I took the fender liner out for access?

Ill have to look behind the trans for room.

Jasonoff

A local guy here welded and machined an adjuster plate that seems to have done the trick.

Start at the 25min mark if the link below doesn't auto start there.

The Machinist

Yeah. Pretty much the idea. If the wear is that bad, I’d likely have to weld before milling for the bushing anyway.

But if all it takes is some weld every 100k I can live with that.

Ludedude

That's where the 9qt Lingenfelter dry sump was mounted for my erector set LS7 Z06

The Machinist

Why I said “most.” But when you spend north of 60 grand on a Chevy, I’d expect at least some adult supervision on assembly of said erector set.

roadtalontsi

This is a bad camshaft. Just came in last week. This makes yours look not really so bad. I'll let you know what the lifter looks like when i replace it this week.

Bank 1 (right side) cylinder 4 intake camshaft.

The Machinist

see if you can talk him into some new CA’s and ship me the junk ones lol...

I bet that thing sounds like a small block Chevy with the valvetrain looking like that.

Jasonoff

You grab a clip of what it sounds like at idle?

roadkillrob

Mine had a few lobes similar to this at 35k miles or so, I had Mercedes look at them (lifters looked totally normal) and Mercedes claimed that amount of lifter wear was normal for the miles on an M156 and would not do anything about it, they did warranty the CA's making noise but cams they said would be good for a while yet before they would consider them an issue. I had some lifter tick on cold start when the car sat for > a week a few times but nothing else. I don't like to see any wear on a cam, but seems it is just a wear item on these cars, I put cams and the newer M159 coated lifters with better oil valves in them and it can sit a month without a noise now and hopefully the cams don't wear with the lifter coating and a better oil change schedule maybe than the first 30k, will see hope to keep the car for a while.

roadkillrob

Mine had a few lobes similar to this at 35k miles or so, I had Mercedes look at them (lifters looked totally normal) and Mercedes claimed that amount of lifter wear was normal for the miles on an M156 I had some lifter tick on cold start when the car sat for > a week a few times but nothing else. I don't like to see any wear on a cam, but seems it is just a wear item on these cars,

I guess the real issue is the cam has a slight angle on the tip of the lobe and that rotates the lifter and gives the nice circles on top of the lifter, once they wear that angle off the cam lobe, then the lifter will stop rotating and the pitting in the cam once worn is like sandpaper and starts to wear a grove into the lifter which eventually will wear through, but it takes a while to happen and you can monitor it and once it starts to wear enough that the lifters stop rotating then it is time to redo the cams and lifters.

Cwagon

Just watched the fore runner video to the one in post #9 and it was interesting that the problem stemmed from the owner dismantling his CA's but not putting the 5 housing bolts in tight enough.
Makes me wonder if I did mine tight enough when I replaced my lifters and did the Tasos pin flip.
Can't remember if I used thread locker or not.
I do remember being worried about over tightening and breaking a bolt.

The Machinist

I was looking closely at that video, it looks like the bolts on that CA are totally missing, which begs the question: where did they go? If they came out on their own, the answer is nowhere good.

I can’t remember if those bolts on the face of the CA are accessible with the solenoid housing bolted up.

At least it’s easy to check.

Loctite is cheap. It’s one of the things I always keep on hand when working with bolts that are labor intensive to get to.

ZephyrAMG

I don't understand....those lobes look fine?....you haven't seen bad lobes until you see some with burnished ends that are really bad. Maybe its just me but your cams look fine.

Jasonoff

They were all there, just sheered off.

Cwagon

Mine has been over a year and 7,000 klm since work.
But might have to pull off covers and check for piece of mind.

roadtalontsi

NOM NOMSSSS. Chicago style deep dish lifter.

BLKROKT

Did that come out of the car you were working on a few posts above?

go team

Sorry about the bad news and also sorry for the delay on the adjusters...

This is all to blame:

New plates






I have some HRC values from the old plates too and was consulting with dkjenis on instagram about making these. The plates above are still yet to be hardened.

Old plates below for reference




As an aside while doing this work I ran into balancing the plates and found out that the camshafts are totally out of balance to begin with. Looking at the intake lobes they are all over the place with the engine’s firing order.