arsupisemnet

Here is info. Order been send to machine shop i used.

arsupisemnet

You need to check on OAL - over all length - with you machine shop. Mine was slightly shorter because or boring machine limitations. Could be little bit longer. Your machinist suppose to tell you sizing.

arsupisemnet

About piston clearance
http://www.hughesengines.com/TechArt...ticpistons.php

olivers

Many thanks! -- I found the same piston-wall clearance article after I posted the question to you. It is very logical when explained the way they do.

v6pwr

Seems like mb is aware of early m278 cylinder/valve premature wear problems. I found an article explaining this issue, besides the chain tensioner problem:

Mercedes M278 Engine Problems and Reliability

Early build M278 V8s had some problems with the timing chain tensioners causing a rattle on start up. The engine has a pretty complicated timing chain drive arrangement. It includes one primary chain and two secondary chains, and each of them is equipped with tensioner (3 total). If not pay attention to knocks/noise for a long time, this may lead to the replacement of the entire chain drive system together with cam adjusters. There were some reports of engine oil starvation due to the failure of the oil pump drive gear (oil pump is driven via a chain).

Also, there were some problems with premature valve guide wear, but later engines don't have that issue. The Silitec coating showed themselves as bad cylinder surface material for operation under high temperatures and detonation. Later, the manufacturer switched on NanoSlide coating which is more scratch resistance.

So, is it possible that mb will cover some of the cost of repair for people with this premature wear problem, whose warranty has lapsed? I think I read somewhere that there was a TSB on this, but I can't seem to find it.

holidaycontrol

Good morning all,

A few questions here, what year do you think MB switched over? I have a 2014 CLS550 4matic and am now concerned with this issue. Also why is GL550's more effected then S550 CLS550 etc? Will doing early 5-8k oil changes help avoid this?

Madhatterman

Good afternoon,

I would like to know at what point the cylinder material was changed? Like the ability to reference VIN # to see if this is something I need to plan on being done to my vehicle..

Anyone have that information?

Thanks

holidaycontrol

After some very extensive research and talking to a lot of people, I'm not really sold that this effects all M278 engines, M157 AMG engines. I think that the GL and it's weight are a factor of stress on the engine but not enough to do the damage shown in this post. Honestly with the amount of cars that have the engine, the failure rate seems extremely rare. We are talking about the models (2011+) CLS550, S550, SL550, GL550, G550 and the AMG models with 3 posts online about this with cars approaching 8-9 years old now, some with well over 150,000-200,000 miles. We are talking about millions and millions of cars with the M278 engine on the road each day and the amount of posts and proof online can be counted on one hand.

The original poster of this post also mentioned that it had looked like the engine had previously been tampered with and that it had a slight off idle for years. Who knows what the previous owner did, if it was tuned, abused, overheated and what happened. He said there is no proof of overheating in the crank but perhaps it was not enough to damage the crank and only cylinder walls. I think the following is true:

-There are bullions for 2011-2013 model years for timing issues that can cause the valves to hit pistons
-There are bullions for 2011-2013 for bad fuel injectors that was rectified
-There are only 2 posts online anywhere on the web about true cylinder wear on the M278 or AMG M157
-if this is in fact a problem with all M278 engines, it could only be a certain number of engines. Say there was in fact a M278 cylinder wall issue, perhaps only a small series during manufacturing at the wrong temp/process. That is why there is no information on this and I can't find anyone that I know or have talked to (5 dealerships) who have seen this.
-if this was a well known issue that effects all engines, we would be seeing a lot more posts and information on this online. These engines are not new and like I mentioned, are pushing 8+ years old and hundreds of thousands of miles now.

What are others thoughts on this?

arsupisemnet

Regarding cylinder wear - it is not noticeable until one day your piston falls apart. I am quite sure you can stretch it to 200k if you really wish for and do not care. Personally i had no idea of this situation before i took engine apart. My main concern was misfire on 5th cylinder which turned out due to leaky valve (bad manufacturing and valve overheat).

arsupisemnet

Once for all good engineering review for scoring causes
http://lnengineering.com/files/2019-...er-Systems.pdf

holidaycontrol

Edited: I thought that this was due to driving on a CEL for 2 years but I now understand there were not many symptoms

BlownV8

My M157 has a bad valve guide - known MB defect. I'm hoping they don't find any additional damage when they take off the heads but we'll see. Cylinder scoring of aluminum engines with aluminum bores is not at all new and happens across all manufacturers. There can be many causes but fuel washdown of the cylinder walls is a common cause as well as overheating. Debris in the engine can also cause scoring. Could be from ingestion of sand, spark plug electrodes or ceramic, piston failures, etc, etc.

arsupisemnet

What is the point of mile long post of being you? Do you have engineering degree or at least basic skills? Do you know all the details?
Back to the subject of being smart @ss. Cylinder wear happened independently from misfire in cylinder. As a matter of fact misfire was due to lack of compression due to bent valve. Now bent valve itself was due to bad casting and manufacturing. Reason for taking a year to fix was very simple - extended warranty didn't honor repair due to no check engine and so on and i had no wish to blow 15k for swapping head. As a matter of fact it would cost in the range of 50+k to deal with engine (unless swapping used POS from ebay), which actually cost me in around 5k by doing it myself.
If there were no misfire due to other reasons the car will be still driven as is and would be driven even more.
If you really concern about your engine you can always stick borescope in the cylinder - which is normal practice, and get it diagnosed. Overall Alusil (Silitec) wear is a well know issue among large number of cars (especially Porch and BMW).

arsupisemnet

Will put little bit more **** on the fan. Where do you think all the leaking gasoline in high pressure fuel injection are vented to? Pick a guess. That will add up to oil washout from cylinder walls.

silvergl

I had the same problem, ended up replacing the engine. conveniently the problem was diagnosed right after the warranty expired, and they refused to honor any of it. In fact, MB USA told me they have had many problems with this central NJ dealer and because it is independently owned there is nothing they can do about it.

I have the old engine listed for sale for parts, non operable. And the same dealer came to me to buy it. When he scoped the cylinders, he confirmed the problem and said that it happens frequently, which is why they were trying to source a block for their customer.

I have documented some of this journey on this site if you are interested in reviewing my posts.

holidaycontrol

I'm sorry if that came across as rude, I really dug into the issue when I read your post. Like I said good sir, I truly respect you for the work you did and I could not have done that myself. No I'm not an engineer but I do hold a degree in another area which involves doing extensive research, data and I based go on fact and evidence. What you are essentially saying is that all M278/M157 engines suffer from bad manufacturing and require a replacement every 70,000. You are stating that this is a more wide spread and serious issue then the infamous 2004-2008 Balance Shaft issues of the M272. Are you saying that every (2011+ with M278/M157) S/G/E/CLS/SL/GL 550 or 63 engine will fail before 70,000miles or have some sort of scoring? If that is what you are saying, that is a quite serious and would probably involve me trading my car in for another model/year to be honest.

Why I'm not doing this is because I cannot find another post, dealership, indy, mechanic other then the 1 or 2 posts I see online with valve issues to the point of requiring engine replacement. If this was an issue of the magnitude of the balance shaft issues of the M272, there would be cases everywhere and a class action lawsuit. If what you are saying is true, then in the next few years, we will see the forums be completely full of M278 bi turbo engine failures requiring replacement or rebuild.

holidaycontrol

Why is this happening to the GL more then any other vehicle if it's the same engine? Thanks for your reply looking at your posts now. Cheers.

mtm

Happens to all cars with m278, not just GL. Here's a video from Russia of the S-class with m278 being rebuilt. Same issue - cylinder wall scoring. The tech says in the beginning: "same old story, same engine." Apparently it's a well known problem there with m278, and using iron sleeves is the only and common repair. You can see scored cylinders at about 9 minutes mark.

holidaycontrol

Thanks I really appreciate everyone reply. If I change the oil every 3000KM instead of the 15,000-20,000 in your honest opinion, will that prevent damage?

Interested to get everyone's input here and again, I apologize for my original post I realize I was completely wrong.

arsupisemnet

Couple comments - standard oil change procedure is 10000 miles not km. In km it will be around 16000.
From all the experience and so on - damage to cylinder walls starts at the moment of iron coating wear off (on the pistons). That was your misunderstanding with my comment. I said - if someone periodically swapped piston sets with new ones let say every 70000 miles (again not km in km it would be about 110000 - which as a matter of fact being normal engine rebuild intervals long way back to my childhood years) the engine will last forever.
What affects iron coating wear - lack of lubrication and carbon deposits. So yes - changing oil every 5000 miles will help (synthetic MB rated). Also if you read article carefully it is saying operation of vehicle in cold climate and on cold affects wear as well. So if you will warm engine up before taking for the road - it helps too. With very simple reason - there is no return line for gasoline fuel injection. All leaking gasoline is vented into crankcase and then evaporated back to intake through vent system once circulating oil is hot enough (ridiculous yes). So if you start driving on cold your oil is getting saturated with gasoline which affects oil wettability and washout.
Everyday we learn something. I didn't knew that too. As a matter of fact i was always concerned why my oil is smelling with the gas.

arsupisemnet

On the comments why you don't hear about it as much
1 - you won't hear it from the dealer (unless the are retarded to say - we designed a s*itty engine which is not last long enough)
2 - only limited number of people can afford dealer engine repair without warranty. Bare engine is 30k. Take engine out 5k. Put engine in another 5k. And so on.
3 - everyone who knew about problems with my car including my dad said - put this s*it back together, swap heads, get rid of check engine light and sell it. Only reason i rebuilded it because i am not a pos to screw someone else
4 - most of the people go for a mexican 2k swap with used 5k engine from eBay. I quite sure they are not going to tell around of doing so - who would want to buy that pos after
There is a reason why MB quietly switched to nanoslide later on.

mcoady1

Hearing what I perceive to be a piston slap at cold start. Goes away after 1 min. Car runs fine except a little rough at idle from an injector that needs replacing (Cyl7 per Indy with Xentry). I'm going to start routinely using Liqui Moli Ceratec to see if it helps. Do you think the ceramic 'coating' will help reduce wear on pistons in the long run?

Also does anyone know if a replacement injector will still function prior to being coded/mated in Xentry? Debating whether to tackle injector myself then just have mechanic code it, but just wondering what to expect when turning on after replacing.

arsupisemnet

Ceratec isn't going to help much.
You can swap injector without coding however it is important to have it coded (just fine tuning of injector performance)

hashim1995

Thank you so much for sharing with us your rebuild story. I'm planing to do the same with my 2012 S550, bought it with 117K from copart with mechanical issue and it has engine knock. Turns out that all cylinders walls were bad so I was lucky to source a good engine block with only 13k miles from eBay and will get new pistons skirts and will start the work this week and my only concern is the timing and how to do it.

Thank you.

arsupisemnet

Engine knock is usually due to connecting rod or main bearings. Anyway buy yourself WIS access from here and you will get all the answers you need https://autosoft.group/