06/01/2026
Nice A to Z job on this early m157 CLS63 PPP.
Results:
675 hp
1063 Nm
Mods:
- Catless downpipes
- K&N high flow filters
- Oil pump solenoid mod
- Stage 2 engine tune
Maintenance and checkup:
- New liqui moly high tec oil and filters
- New spark plugs, indexed and all.
- Cylinderwalls inspected for the dreaded m157 scoring.
Those familiar with the 5.5 biturbo m157 will know that these engines are a powerhouse, but they have some achilles heels to pay attention to.
Any m157 we mod will get a cylinder wall inspection and spark plug indexing to ensure the best durability.
Mercedes has an official TSB stating the importance of indexing the spark plugs (making sure the angle of the electrode faces towards the injectors) to ensure a clean and efficient combustion. Not doing so can result in detonation and destroying pistons and cylinder walls.
Now according to mercedes, when using their spark plugs there is no need for any adjustments, just tighten to torque and they are indexed. This is incorrect, as you can see in the image the line on the socket faces towards the injector, and the electrode is completely opposite to that line.
Mercedes branded spark plugs are identical to the Bosch spark plugs, with the same exact bosch partnumber.
Unfortunately for the mechanic and customer this means that the copper washers have to be ground down to the correct thickness to ensure correct indexing, making a simple job like replacing the spark plugs, an insane amount of work…
Besides this we always modify the oil pump solenoid to ensure sufficient oil pressure under all conditions, making for a faster warm up of the engine and a smaller risk of premature wear on the pistons and cylinderwalls.
These point combined with good quality oil will ensure these engines last for as long as possible.
Hit us up if you want reliable and safe power from your 5.5 biturbo 63 amg!
