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

 

Per the engine specs in the Service Manual the SRT6 compression pressure is 689 kPa (100 psi).

 

It sounds extremely low. I think they mean 200 psi

 

I did a home compression test a few years ago. I got 149 psi warm with almost no variation between the cylinders. I cranked for 5 rotations each cylinder.

Les

 

 

I saw the values on the service manual to, and that cant be right. Supercharged engine has lower compression ratio, that is something people
Mix together. I do understand your thinking. Did it my self. Compression ratio and Compression pressure

 

Thats a healty engine.
i have talked to mechanic on Mercedes, No one else knows. Its a riddle.
11 - 14 bar , 159,5 psi - 203 . psi . Very good engine. super
10 - 11 bar, 145 - 159,5. OK
9 bar, 130,5 psi. Bad engine. No pressure

 

Good, bad or super I don't know. 11.9 at 117 mph = my 149 psi. 24,000 miles +o- (sea level) You can see what I've done to my car. It's real data, use it if it helps you.

Les

 

Thank you Velociabstracy. Its real data i want. 11.9 is super