C43 2017 knocking sound from left bank only
Newbie
Joined: Jun 2025
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c43 amg coupe
Out Of Control!!
Joined: Apr 2019
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From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
EASY DOES IT
- belt
- idlers
- tensioner
Junior Member
Joined: Oct 2024
Posts: 52
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From: Finland
if it's not eating oil, and not knocking then it's usually just cosmetic.
But all of them should have the oil solenoid deleted for good oil pressure.
Mine has, and is driven hard with 225k km on the clock.
Some cylinder markings but it has not changed for 30k now.
Out Of Control!!
Joined: Apr 2019
Posts: 11,958
Likes: 6,797
From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
Most of the Alusil engines have some bore scoring marks after some use, but they still have good compression and run just fine.
if it's not eating oil, and not knocking then it's usually just cosmetic.
But all of them should have the oil solenoid deleted for good oil pressure.
Mine has, and is driven hard with 225k km on the clock.
Some cylinder markings but it has not changed for 30k now.
if it's not eating oil, and not knocking then it's usually just cosmetic.
But all of them should have the oil solenoid deleted for good oil pressure.
Mine has, and is driven hard with 225k km on the clock.
Some cylinder markings but it has not changed for 30k now.
How long ago did you delete the oil solenoid ?
Now you have good pressure ?
What cylinders are scored 1+4+5 ?
Junior Member
Joined: Oct 2024
Posts: 52
Likes: 8
From: Finland
Solenoid delete around 190k and all cylinders show some light scoring, left bank little more as the pressure side is at the "wrong" side.
Tuned to around 430hp and when it blows I will sleeve the block or some other block.
I have the machines to do it myself.
Tuned to around 430hp and when it blows I will sleeve the block or some other block.
I have the machines to do it myself.
Last edited by MJPfin; Jun 9, 2025 at 03:49 AM.
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Out Of Control!!
Joined: Apr 2019
Posts: 11,958
Likes: 6,797
From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
ENGINE INTERNALS DAMAGE
I am curious to know what make these engines knock...
the piston skirts ?
the rods bearings ?
unequal pressures ?
bad timings due to uneven leaks ?
and what does score cyl. bores...
bearings material ?
Alu-Sil shavings ?
Junior Member
Joined: Oct 2024
Posts: 52
Likes: 8
From: Finland
Lack of lubrication from the stupid oil bypass valve scoring the bores.
And wearing out the piston skirts, you get piston slap when cold.
Another thing that is scoring the cylinders is idiot users hammering throttle hard when cold.
Effectively expanding the pistons faster than the cylinders and cold seizing the pistons.
And yes you can bore out the block to sleeve the cylinders with iron sleeves. Just like any engine out there.
Or interference fitting new alusil liners but thats stupid expensive as the sleeves are very expensive.
And wearing out the piston skirts, you get piston slap when cold.
Another thing that is scoring the cylinders is idiot users hammering throttle hard when cold.
Effectively expanding the pistons faster than the cylinders and cold seizing the pistons.
And yes you can bore out the block to sleeve the cylinders with iron sleeves. Just like any engine out there.
Or interference fitting new alusil liners but thats stupid expensive as the sleeves are very expensive.
Out Of Control!!
Joined: Apr 2019
Posts: 11,958
Likes: 6,797
From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
Lack of lubrication from the stupid oil bypass valve scoring the bores.
And wearing out the piston skirts, you get piston slap when cold.
Another thing that is scoring the cylinders is idiot users hammering throttle hard when cold.
Effectively expanding the pistons faster than the cylinders and cold seizing the pistons.
And yes you can bore out the block to sleeve the cylinders with iron sleeves. Just like any engine out there.
Or interference fitting new alusil liners but thats stupid expensive as the sleeves are very expensive.
And wearing out the piston skirts, you get piston slap when cold.
Another thing that is scoring the cylinders is idiot users hammering throttle hard when cold.
Effectively expanding the pistons faster than the cylinders and cold seizing the pistons.
And yes you can bore out the block to sleeve the cylinders with iron sleeves. Just like any engine out there.
Or interference fitting new alusil liners but thats stupid expensive as the sleeves are very expensive.
It's can of amazin' how these days pistons are supposed to run dry without active squirters.
Savy owners are sold on ....
"oil causes friction"
"thin oiling saves gas"
One of these engine with all new sleeves, pistons and bearings... way to go!!
