Guran

Hi
What is a normal healthy compression pressure in a M112 engine ?

Guran

Wow. has nobody tested the engine. its a big difference in horsepower depending on cylinders pressure and compression pressure

mars-red

I can't help answer your actual question, but in regards to why nobody else is answering either... I get the impression that nobody gets enough miles on these motors for that level of cylinder or valve guide wear to occur. Seems like what takes out C32s / SLK32s is accident damage, heart-stoppingly expensive computer/electronics repairs, or catastrophic internal engine failure, rather than "normal" wear. I think the highest mileage C32 I've heard of so far was around 160k. I wouldn't expect engine wear serious enough to affect performance at that mileage, but I'm watching this thread for my own curiosity.

How many miles do you have on your motor?

Guran

Thank you mars-red. My engine is 110 000 km. Compression test 10.7 bar. And that is good. According to a Mercedes technician, 11 - 14 bar is very good. 10 - 11 bar is ok. 9 bar is bad. No horsepower. I cant find specs on this, but i believe him. Unfortunately i got a bad fuel injector when i was upgraded the engine and that fuel injector killed one cylinder. I bought a used engine. No power at all. Compression test 9 bar. Probably i must change all piston rings . But which engine. The old one. Think so. Interesting would be to know what pressure people have in their cars

Pocketzest

Just tested my 2003 C240 with 180k miles

1-180psi
2-180psi
3-190psi

4-165psi
5-170psi
6-168psi