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Iron liners can score, because it has happened since day 1 of the internal combustion engine. The question is, are later M278s (or even M157s) somehow, fundamentally, better and longer lasting? Do we really have data on this? We know early timing chain systems are problematic, sure. But that's only the start of the potential list of issues.
Indeed, scoring marks does occur even in the factory, but the real issue arises when the piston rings exceed their wear limits and malfunction. In such instances, since the engine must be removed, it would be logical to rebuild it with superior racing components.
Hey guys, didn't know where to post this information, as I have been getting many DM's and emails about it. And i didnt see a thread revolving around this information so i figured start it here for you guys to discuss.
As many of you may or may not know, Mercedes Benz M278 V8 engine used silitec cylinder barrels for many years. This is the Aluminum-silicone cylinder treatment.
As of March 16th 2015,
Engine number start : 2789xx 30 266191, Mercedes change over to cast iron cylinder barrels. Along with new pistons and rings of course to match.
Appreciate this information 👍
This eBay engine was posted in another thread so I figure I’d post it here so we can get possibly understand just when and if these sleeved M278’s were produced.
Of course as the old saying goes, if there aren’t pictures, it didn’t happen 😀
I’d love to have someone post a picture or link a video with these 2015+ engines with sleeves. I didn’t find one in this thread.
To preface this,
Have a friend who contacted me about trying to help them find an M278 block for their project….
He’s just about to get his block sleeved instead. We have yet to find any M278’s with cast iron liners.
I look forward to anyone who can post a picture of these cast iron sleeved blocks. I’d love to see one in the flesh. So far this is Vaporware.
I have also gone to look at several (4) engine cores locally 2016+ none were sleeved, but this the eBay engine that was posted in another thread…
It is Identified as a 2017 M278.
It is numbered 30 316114 so should fall in the cast iron sleeved range.
You can CLEARLY see from the pictures this block is NOT sleeved (no cast iron liners)
So the question is, does anyone have any pictures of these sleeved blocks from Mercedes?
Thoughts?
Here is the engine number from listing:
I think we can all see this eBay engine block is aluminum all the way thru i.e. no cast iron liners/sleeves even though according to serial number it should.
No way this is Sleeved…
The scratch on cyl 4 also shows aluminum all the way thru, no cast iron.
Last edited by crconsulting; Sep 8, 2024 at 07:27 PM.
I am kind of tired of kicking dead horse, people don't take an advice when universe gives them a gift. Attached photo is a original MB M278 block with cast iron barrels, which i have in my possession. I don't know about date it was manufactured but it gives you an idea how it suppose to look like. It is under bunch of other things in my garage so i don't really want to move things around just to look at the date. Same look as the one i showed on that eBay listing. I am not affiliated with seller, just gave an advice
If some one is smart enough he will grab that short block of eBay. All it needs is a set of bearings, aftermarket rings, and good wash in industrial parts washer. May be one pass of flex hone to remove glaze and prep for new ring set.
Now since i am the one who machine blocks of any kind on daily basis in the pictures with cast iron barrels or cast iron aftermarket sleeves you would see honing marks which is not present in Silitec sleeves unless some idoits got their hands to it. There is no regular honing procedures on Silitec barrels.
Attached photo is an original MB M278 block with cast iron barrels, which i have in my possession. -
I don't know about date it was manufactured but it gives you an idea how it suppose to look like.
Thanks so much for taking the time to post a picture 👍. We’re all super busy and always appreciate when someone takes the time to add something positive to the discussion.
That’s exactly what I was looking for. Though it can be tough sometimes to see details in some web pic. From your newest picture, they appear to be either “cast in” liners, or some other additive machining process similar to mirror bore technology using the HELLER CBC 200’s at the Stuttgart plant. Probably why you can’t see a separation between sleeve and block on the eBay engine block. They don’t appear to be pressed in. I think @chassis (and I) expected to see press in liners….
So that clears up a few things. Funny you mentioned the honing, though sometimes tough to judge from pictures, I agree, my initial thought was someone tried to hone it, as surface finish is atypical than one would expect to see on Nanoslide/Silitec bores but would make sense since they used different rings for the iron bores.
I’m not sure if the production number switchover is accurate, something may have gotten lost in translation. But will pay closer attention to engine numbers to verify.
Originally Posted by arsupisemnet
I am not affiliated with seller, just gave an advice
We appreciate it 👍. I did pass the listing on since these USABLE 15+ later engine cores are somewhat difficult to find at this stage…..
btw retired now but worked as an MB tech, later moved to the machine tool industry 35 years total. Have spent entirely too much time behind a CK -10 so have a fairly good grasp on this subject 😀
Thx and Good Luck!
Last edited by crconsulting; Sep 10, 2024 at 11:34 AM.
2004 E 500 4MATIC Wagon; 2015 ML 350 4MATIC; †2003 C 240 4MATIC Wagon (2003-2022)
I'm not sure whether this has been discussed in here, but Tasos Moschatos' theory about a contributing factor to the M278 cylinder scoring issue (i.e., https://youtu.be/unYOuglDIcM?si=uR8iJnZejDefx9Y8&t=90) and a possible preventative measure(i.e., https://youtu.be/unYOuglDIcM?si=4Dut7z0_VXcW7o7z&t=45) is something that I have taken up with my own shop's techs in recent years...
Last edited by Œuvre; Sep 10, 2024 at 02:39 PM.
Reason: Edit to preserve URL reference.
It been discussed thousand times, there is no preventive measure for it. Once factory coating is gone it is ticking bomb. Only way to prevent is to swap pistons every 50k miles with stock tune, or 30k with high boost. Or get pistons coated with something like that https://industrialhardcarbon.com/coa...e-crn-coating/
Most of the people doing this kind of videos just looking for audience to believe their crap
Why are not more folks talking about unplugging the oil pump DUMP valve? It makes so much sense for owners to do and there really is no downside (well, maybe a tiny bit of fuel mileage???). The scoring is a lack of Oiling issue, not a coating issue as some would have you believe...
Why are not more folks talking about unplugging the oil pump DUMP valve? It makes so much sense for owners to do and there really is no downside (well, maybe a tiny bit of fuel mileage???). The scoring is a lack of Oiling issue, not a coating issue as some would have you believe...
yes, very true!
The oil pump solenoid shifts the pump volume from low to normal volume. It does not dump or bleed out pressure. It physically switches between small pump vs. normal pump.
That feature detunes the engine and limits pistons heat removal. The VVT positioning directly benefits from stable oil viscosity.
Driving around on low pressure with low viscosity leads to excessive oil consumption from stuck rings.
Once again "professional" advices do more harm.
"Once solenoid activated it minimize oil pressure, without electricity pump pumping at 100 percent"
That is not "dump valve". That is control valve for housing geometry
Okay, so calling it a "dump" valve is too extreme then... When the solenoid is energized by the PCM the oil pressure is reduced and at the reduced pressure there is not enough oil pressure to overcome the check valve springs in the piston squirters, so no piston cooling or added cylinder lubrication at lower RPM, and inconsistent pressure to the VVT system. Does that sound about right? I have about a thousand miles with mine unplugged and it runs like a scalded ape - might be my imagination, but it seems a bit more snappy with the Go pedal...
Okay, so calling it a "dump" valve is too extreme then... When the solenoid is energized by the PCM the oil pressure is reduced and at the reduced pressure there is not enough oil pressure to overcome the check valve springs in the piston squirters, so no piston cooling or added cylinder lubrication at lower RPM, and inconsistent pressure to the VVT system. Does that sound about right? I have about a thousand miles with mine unplugged and it runs like a scalded ape - might be my imagination, but it seems a bit more snappy with the Go pedal...
yes Dan, that is 100%
scaleded ape LOL
accelerator response: yes definitely!
It cancels the factory lag.
To further cancel extreme piston heat you can gradually switch to better oil viscosity as the cylinder lost compression are restored.
Hello, my M278 engine number: 27892930304635 the car Production Date 2016-03-07 Can you tell me which one is my crankcase cast iron cylinder barrels? or silitiec? thanks.
I am kind of tired of kicking dead horse, people don't take an advice when universe gives them a gift. Attached photo is a original MB M278 block with cast iron barrels, which i have in my possession. I don't know about date it was manufactured but it gives you an idea how it suppose to look like. It is under bunch of other things in my garage so i don't really want to move things around just to look at the date. Same look as the one i showed on that eBay listing. I am not affiliated with seller, just gave an advice
I'm wondering how to find out without opening the engine and baroscope, otherwise I'm not so stupid that I can't distinguish visually whether it's iron or aluminum.
General information for engines with cast-iron cylinder barrels
and with Silitec cylinder barrels (aluminum-silicum cylinder
barrels), conversion as from March 2015 or as from engine 2789xx
30 266191 for cast-iron cylinder barrels
General information for engines with cast-iron cylinder barrels
and with Silitec cylinder barrels (aluminum-silicum cylinder
barrels), conversion as from March 2015 or as from engine 2789xx
30 266191 for cast-iron cylinder barrels
Iron liners have cross-hatched (honed) appearance.
Non-iron liners have a mirror finish appearance.
The different appearances can be seen using a borescope. Having said this, a user on this site has reported scoring with cross-hatched bores with an engine number that predates the stated changeover point to iron liners. Questions remain.
I wouldn't call M157 or alusil M278 "Junk". It's not fair to call it Junk just because it's less durable than lexus. I have seen rebuilt video that shows no scoring well above 100k for M157. It certainly requires you to pay close attention and do oil regularly. But it's part of the game, you have to pay to play.
I didn't regret to own a M157, you get amazing performance out of the box and with a good understanding of the engine you can manage your level of expectation on reliability.
It appears that the issue may not be related to a specific factor. Mr Tasos Moschatos has expressed curiosity about the matter in a video, in which he identifies various components of the engines as potential contributors to the problem. While it may be optimistic to expect a $100 investment in an oil change every 5,000 miles to extend the engine's lifespan, it is certainly beneficial. However, it should be noted that this will not prevent your engine from failing.
(reply to old question, for clarification)
@Tynee your engine is the 642.826 Diesel.
Considered a very long-life engine if the oil cooler seals are purple Viton either from the factory or if OEM were replaced.
You can google the MB assembly line update date to find if yours is the purple Viton (mid 2010?)
I can confirm 2016 m278 with iron sleeves. Recently purchased a 2016 m278 with 110kmiles to replace my scored 2014 m278 (doing m157 turbos, flex fuel and all other prone problems while I'm at it) put a camera in each cylinder, zero scoring on any of the cylinder walls other than the factory marks and the factory honing marks(which will only be on iron sleeves) . I believe a lot of you guys including me a little, were skeptical about the update of the cylinder walls but I can confirm its updated on the 2016 model 278 engines. I'll add pictures of the walls in the weeks to come as I prep the engine.
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M278 CYLINDER WALLS
