what is BMW's toughest/most robust engine?

[pistonheader]

is it the M30? someone told me it's BMW's longest serving engine (over 25 years apparently!) and said the bottom end is basically bullet-proof.

just curious...

cheers

[pilly]

hmm, not quite sure which engine it was but i was watchin this show on tv about BMW factories and they said that some of the older blocks were chucked outside in the rain and all the workers peed on them. Apparently it 'weathered' them

[Jeroen]

That was said about the M10, preparing them for use in F1 as M12/7 bottom end to produce up to 1300 HP!!! Not sure if it is true, but I've heard the story from many sides, including from a friend of Paul Bracq (BMW designchief and the designer of -among others- our beloved E21).

But the M10 4 pot and M30 6 pot have a lot in common and these are definitely extremely strong and reliable engines. 400+ K kms is no exception.

[323baur]

I think M30, specially the 2800.
The bigger ones have sometimes leaking cilheadgaskets.
I saw last one with 685kkm. Runs like new.

[Peter V.]

The story about the M10 engines i heard more often.

They would use old engines and let them stay outside to reduce all the stress of the metal. If the bottompart of the engine was good then it was ready to get (ab)used in the F1 car.

[e21-Mark]

I'd go with m10 or m30. Both are supposed to be bullet proof.

[pistonheader]

My M10 often needs 1 second or so to build up oil pressure on cold starts, richard at fritz's says it's the return valve on the oil filter...but it's an official BMW one it never did it that long ago

runs sweet as a nut once it has pressure though.

[Jeroen]

Believe that valve is on the pump rather than on the filter...

[tommi_e21]

m10 all day baby! its gotta be!!!!

[Millar]

gotta be the m10 for its love of boost!

[nas80]

m50 its got a forged crank.

tell you what most engines can last as long as you take care of them n treat them right.

[pistonheader]

i thought the M10 had a forged crank as well? what is the cylinder head made of on an M10? pretty sure it's not aluminium...

[e21-Mark]

Yes it is.

[pistonheader]

Yes it is.

yes it's a forged crank, or yes it's ally

i'm going to take a lucky dip and say ally

[tommi_e21]

alloy head and doubt its a forged crank.