b€nz

Hi all,

I bought an e55 amg s211 a few months back. Recently it started a dreadful knocking sound. I removed the valve covers in hoping for a valve failure or something. After boroscoping the cylinders i found the culprit. 1 piston in the cylinder had a hole, i think it was detonation due to a bad tune.

So my question is, what is the root cause of this problem. The engine was running strong, and the remaining internal parts is suprisingly clean. And what is the best solution, rebuild, buy an engine block and swap over parts, or an entire new engine?

Background info about mods engine wise: Long tube headers, x pipe. 77 mm pulley. Belt wrap kit. And a retune.

Photos:

The fauly piston/cylinder

The faulty piston/cylinder

SICAMG

Cheapest....find a used engine.
Expencive ...rebuild it and that will take ALOT more time and effort.
You can piece it together by swapping over to a good block and pistons but again more time and money and you better know what your doing because it will be some work.
Also you may have a bad injector on that hole so check them all out for sure.

b€nz

I will check the injectors, do you think it may have stuck open or pushed in too much fuel? And i'll do most of the work my self. i will only let the machine shop hone and sleeve or such the cylinders if i choose to repair the block. I live in sweden and there is no engines here, and if thefe are any they are so expensive.

SICAMG

Your looking at around 5-6 thousand for sleeves and pistons so be ready for that hit !!

ls1_mast

sorry to see that you have this issue man

if this is cylinder 4 or 8 then it is common for those cylinders to go bad due to fuel starvation ,,,as @SICAMG said inspect the injectors for those two.. and cylinder 4 and 8 is the back cylinders the last ones ... closest to the fire wall

77mm pulley on the stock injectors is not maxing the duty cycle of the injectors so it is a low probability that duty cycle could do this but since the car is old you may have a bad injector or a bad tune ...

if your bore is ok then you can rebuilt it but the trick is that u will only know that once you remove the cylinder head to inspect and measure the bore

ls1_mast

my openion is get a used engine and use this one for the future parts ... will be less cost on the short and long run ... but also change your injectors on the new to you used engine and install the 550cc or the 630cc bosch injectors with a tune and you will be good to go

also double check your fuel pump flow to make sure it is not the cause of the issue . to do that you need to connect a pressure gauge to the fuel rail end while the car is running on idle to see what pressure you get .. the car should be running for awhile to make sure that the fule pump is already hot and stressed ... these cars produce 83psi of fuel pressure on idle