For Posterity Sake - Early vs Late M20 subframes side by side

[Twelvizm]

As far as I can tell, they are very similar, other than the early subframe hold the motor about 2" further forward. These photos are now the only reference I have, as I've sold off the early model subframe.

















I did line up the motor mount arms, and they appear to have the exact same geometry, with all holes lining up. The later arms are about half the weight of the early. The early are made of the same gauge of steel as the subframe, whereas the late seems to be cast alloy.

The subframes themselves, now that I've looked at them a little more, seem to hold everything in the same position. This as the frame rail holes are off by the same amount as the motor mount holes. When stacked on top of one another, the steering rack mount, motor mounts, and frame rail holes, all line up with one another. The only difference I can find is really just the shape of the subframe, but the geometry is the same. Is this right, or am I seeing things? I can only find that the angle in which it holds the control arms is different.

[jjgbmw323]

I am using the old subframe with the new subframe arms on my 3.0 m20, and no issues, so it seems they line up and the arms are interchangeable....

[Tom D]

the newer subframe (9/78>) locates everything in exactly the same place as the older model except for the pivot points for the lower control arms, they have been moved forward and the newer LCA's have a sweep back shape that puts the wheel hub in the same place as the old.

[Mike323i]

Correct. As has been gone round many times, the subframe, control arms, and sway bar are different early and late and must all three be used in conjunction.
Everything else is the same and interchangeable.