M120 - What should I set as the new rev limit?

[StuartBJ]

Hey guys, I'm currently setting up my megasquirt and im wondering what I should set as the rev limit for this engine. I will be running with only 1 or 2 ancillaries; alternator and maybe water pump (I have an electric one also before you panic) so the engine should rev more freely anyway.

Was the original red line at 6500? I can't remember

Opinions welcomed

Anyway must dash, the f1 is about to start.

Stuart

[duxthe1]

I wouldn't push the old lump too hard. The M120 is one of the few MB engines I've seen suffer catastrophic failure in the reciprocating assy. that wasn't oil starvation related.

[Turbo E320]

The original 6.0L M120 powered Pagani Zonda's had stock M120's in them that made 402hp/421tq(basically stock power) with the redline raised to 7500.

[JayRash]

i would say 7k is abt as far as u would want to push the timing mechs, and keep in mind the main crank has 12 rods and 12 pistons to deal with.

[MAG58]

It's a big motor, but for all intensive purposes, the M120 is just the euro EFI 104.98 x2. I'd base my rev limit off of that number and drop it a little do keep crank movement in check (though pagani does spin a stroker version 8k with an alloy block) and turn it 7k, like jay said. You can always drop it if it runs out of breathe before then, I'm not sure if the cams on the 120 are as conservative as they are on the 104.

[Roncallo]

As installed in the 1996 US spec SL600 the red line was 6000. I would dyno it before making any decisions to increase red line. You might find you don't gain anything.

[Dearlove]

isnt the v12 a "perfectly' balanced engine??

[JayRash]

perfectly balanced doesnt negate the fact the crank has to deal with 12 rods and 12 pistons jumping around.
As for the cams i would bet they are standard M104 issues but i do believe the M120 has the ability to reach 7k

[StuartBJ]

Thanks gents,

Given the fact that I don`t want the headache or cost to rebuild this engine I will set it as per stock to begin and turn the wick up if it yields and difference on the rolling road.

Thanks again
Stuart