Any way to identify m20 easily?

[InuFaye]

Hello all,

I just bought an 87 325is, and the guy said it was not the original engine. My question is there an easy way to tell which kind of m20 is in this car? I know its an engine out of an "I" because the ICV is in the intake boot but other then that I have no idea.

Thanks Guys.

[Aptyp]

putting up a pic would be the best way to get your answer.

[jlevie]

Short of tearing the engine down or getting dyno data you can't tell if it an M20B25 or a hybrid of M20B25 & M20B27 parts. That said, if it looks like an M20B25 the odds are good that it is.

[jasonsnoddy]

see if it revs to 7k?

[Kershaw]

Short of tearing the engine down or getting dyno data you can't tell if it an M20B25 or a hybrid of M20B25 & M20B27 parts. That said, if it looks like an M20B25 the odds are good that it is.

this

[e30Matt]

Intake manifold and head casting numbers are good indications if the engine hasn't been torn down.

[scottinAZ]

if it looks like an octopus is fucking your valve cover, you probably have an M20

Other than that, check casting numbers, and there should be a designation on the head (2.5, 2.7eta, etc) but this still isnt foolproof