audifreak

Recently was getting a lot of sound from the tappet. Opened up the engine and the common camshaft/tappet problem happened.
The camshaft and the tappet had to be changed. I think this has been an ongoing issue with the M156 engine.
However what shocked us was the engine cylinder head got damaged as well. So now I need to look for a right side cylinder head. Part number A1560108920.
A new one cost and arm and leg, looking for a used one. If anyone knows where I can find one, would be much appreciated. Thanks.

Phil1305

What does the cam and lifter look like? Curious to see how they look causing that.

audifreak

I don't have the pictures of the cam and tappet on this cylinder head.
But this was from the left cylinder head:



camshaft worn



tappet worn and tappet hole.

Phil1305

how many miles were on this engine? What oil did you use and how long did you go before changing it? 5k, 7k, 10k?
Just trying to gather more diagnosis on what contributed to this more than we already know about the cam problems in these engines.

audifreak

Oil change about 10,000km. Should have done it at 5k instead..I know.
Have mainly used Mobile1, but decided to change to liquid moly at the last oil change since many good reviews from guys here.
Car is coming to 10 years, so its about time to change the camshaft anyway.
Now just trying to find a cheaper way to replace the cylinder head. Was quoted about USD6,600 for a new one....

go team

Check eBay there’s a whole bunch for cheap. You may need to reuse your bridge caps. I have not seen used heads with bridge caps attached. If you do find a set with caps and find yourself with a spare I would love to have even just one bridge cap 😅

roadkillrob

Wow those are seriously worn out, I have seen a few that bad in Tasos' videos but never seen one so bad it damaged the head.

I would check ebay as there are lots there that ship worldwide also or any local auto recycler as they typically are all on the same system that shows parts available at other recycling yards and can track down the part.

Here are a few that will ship to Singapore

https://www.ebay.com/itm/MERCEDES-W2...EAAOSwe5ZdZDfk
https://www.ebay.com/itm/10-11-W212-...f3BNJ#shpCntId

Jasonoff

How loud was it at idle? With that much wear, it must have been pretty noisy.

BalanBro

Not sure how it'll work since you're in Singapore, but I did a quick search on www.car-part.com (North American part search) and found several complete right cylinder heads ranging from $600 to $1200 US.

audifreak

it wasn't that particularly loud. most of the time it goes away after a while.
but last week it suddenly was very loud and so I brought it to the workshop for a checkup.

audifreak

thanks for the links. will look for the cylinder head online.
Does anyone know where to get piston rings? Apparently MB doesn't sell just the ring, it comes with the piston and cost a bomb.

The Machinist

Cant help with the where but I can help with the what.

M156 has some fancy high tech coating on the cylinder walls that require a special kind of piston ring. Traditional cast iron bore engines have rings with outside edge profiles that are parallel to the cylinder bore.

Engines that have Alusil, Nikasil, Nanoslide, et al... cylinder walls all have special rings with a slight radius on the edge to prevent the ring from digging into the cylinder wall.

If you use a ring designed for a cast iron bore on your M156, you will destroy the engine. Make sure you get the right stuff, wherever you get it from.

audifreak

Thanks everyone.
I need to but a lot of parts for the repair. Which website I can purchase cam shafts, fuel pump, water pumps etc... I only know FCP euro and they don't have every part I need. Thanks.

Helamanofa

Sites that have a more wide range of oem parts for the engine and fuel system would be mbparts, autohazaz, and eBay. Those are the only ones I can think of off the top of my head. You just need to know the part # and you should be good to go.

audifreak

Thanks. Everything is out now. Just waiting for parts to arrive.

audifreak

I have the P31 development kit. This is what the forged piston looks like it.

Cwagon

The piston/conrod pic clears up the argument whether these engines had forged conrods or not as well as piston and crank.
You can see the cast AMG on the big end.

The Machinist

Please post closeups of the crank counterweights and crank webs if you are willing.

I am wanting to get a handle on final machining processes for the rotating assembly.

audifreak

Sure. I should be dropping by the workshop next week again to drop off more parts when I receive them next mon-wed.

VektorPerforman

What is the tell you are seeing that verifies forging over casting?

Jasonoff

Clears up that they're cast rods, not forged.

Cwagon

Sorry I meant to say "aren't forged" as you can clearly see the casting AMG on the rods.

audifreak

Hope this helps:

The Machinist

It does. Thank you.

I was aiming to get a handle on the manufacturing process for these cranks.

What I can see is that it is drop forged, then twisted while red hot, probably run through one more forging die, then quenched, then tempered, then rough machined, the journals induction hardened, and finally ground.

Probably stronger than a billet crank.

Although it does give me a hankering to hear one of these with a flat plane crank.

audifreak

If u need more pics of other angles let me know. I will be dropping by the workshop again on Friday to hopefully drop off the camshafts.