Why they "think" that 3 valves per silinder is better than 4, whitch they used before eg. M119 & M120

The single exhaust valve per cylinder made for much faster warmup of the catalytic converter. This greatly reduces exhaust emissions. The M112 and M113 are rated LEV engines; very clean running for the time they were introduced.

- JimY

4V architecture>3V architecture

I'm sure that 3V is cheaper and better for emissions though.

so this is basically a step-back according to performance?

Well, yes and no. 4 alve architecture is superior to 3 valve architecture, but one simply having more valves than another does not make a better engine automatically. It is a step back as far as the design goes, but thanks to other changes, a lot of the newer 3v engines are outperforming the older 4v engines.

well yes, you are right but 99% newer engines (doesent matter what car) give bigger power output. But when i compare 48v 600 (300kw) and 36v 600 (270kw) I see that newer engine hasnt got the same performance, it has even less... twinturbo powerplant doesent suit in to the comparison, cause old 48v twinturbos were never offered (too bad ) altought newer engines are Way economic than old ones I bet...
Ok I got my answer to the question anyway.

$$$$ was the biggest reason for the change to the 3 valve MB engines!

MB made a good engine for a LOT less $$$ than the 4-valve engines that they were & now are making again!

__________________
MERCEDES Benz Master Guild Technician (6 TIMES)
ASE Master Technician
Mercedes Benz Star Technician (2 times)
44 years foreign automotive repair
27 Years M.B. Shop foreman (dealer)
MB technical information Specialist (15 years)
190E 2.3 16V ITS SCCA race car (sold)
1986 190E 2.3 16V 2.5 (sold)
Retired Moderator

Agree - they told us the engines were better but they told Wall Street they cut out half the cost.

Does the SOHC 3 valve engine still have variable cam timing?

__________________
Current Crop:
2002 ML500
1997 SL600
1969 Corvette (for sale, perfect shape)
1984 RX7 GSLSE

Wanted:
a diesel MB!
Looking for a new SL.

No they don't..

__________________
MERCEDES Benz Master Guild Technician (6 TIMES)
ASE Master Technician
Mercedes Benz Star Technician (2 times)
44 years foreign automotive repair
27 Years M.B. Shop foreman (dealer)
MB technical information Specialist (15 years)
190E 2.3 16V ITS SCCA race car (sold)
1986 190E 2.3 16V 2.5 (sold)
Retired Moderator