380 SL Euro model Engine
 

Does anyone know why the Euro 3.8 V-8 can tolerate such a higher compression ratio?

Does it have a sleeved engine or lined or hardened in some way?

I built a 380sl engine at 9.2:1 and it lasted about as long as a paper collar in a hog fight. Less than 37k miles before it melted a piston and scored the cylinder wall to the no-fix-it level.

I think the Euro model is at least 9.2:1, I can't find where I saw the specs.

The Euro 380 was 9.0 compression ratio, from tests at the time reprinted in Brooklands Books' Mercedes SLs and SLCs Gold Portfolio, 1971-1989 (a useful and inexpensive reference). The US was 8.3, and the Road & Track test of the 380 when it came out makes no mention of any difference in the treatment of the cylinder bores, which were chemically etched to expose the hard silicon particles in the alloy and create a hardened surface for the iron pistons.
Other than the timing chain issue, the 380 engine has been as bulletproof as the other versions of the V8, based on the majority of what I read.

If you bored the cylinders, it probably wiped out the hardened surface. And then it would've been a sure thing for you to meltdown the engine...

I have a service manual for the 380 engine which covers the following engine types.

116.960, 116.961 116.962 and the 116.963.

This manual also states that all engines have a compression ratio of 8.3:1

hope this helps

Cheers
Damian

i am not sure of it but i think the block is silicone impregnated. i dont see why a bore would ruin it/

if you melted a piston i think you must have had a lean running condition. a euro engine should last as long as a us spec, imho.

tom w