Hello all, thanks in advance for your knowledge-

I've spent a few hours with the search function and only have more questions. I began working on the front end of my 71 -4, starting with 320i ATE caliper conversion to help stop my 2430 monster. I intend to add front swaybar, replace the shocks, control arm and strut bushings and probably turbo tie-rods as well - but came upon a problem after fitting up the calipers. I have the sneaking suspicion that my car has later spindles.

See the pics below, the caliper is offset to the inside and almost rubs on my rotor at the outboard side. My understanding is that the 320i caliper will bolt up to the early spindle and be offset toward the outside. Also, my rotor is about .02" under min spec, so I need new ones... the caliper might not fit at all with thicker rotors. Here are my questions if you can help to figure out before I start ordering any more parts:

1. How can you tell the difference between an early and late spindle/strut tower?
2. Can you tell the difference by the rotor? Since I need to get new rotors and bearings, they will have to match whatever spindle I have or purchase to replace. same with the ball joints and bushings I imagine.

3. I'm not opposed to buying raised spindles to install, would these be compatible with the calipers without machining them? Or I can try to order a complete set of early suspension to rebuild and install. I like the way my car sits now with 15" rims, and my control arms have the u-channel for sway bar drop links. I do not want to do any welding for a bump-stop bracket.

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I'am sure I read on here the BMW calipers have to be machined to @ the mounting ears (inside) .

That is correct only for the later years, the Pelican tech article also confirms this, but mine is a 71 and should not need to (unless the struts are swapped...)

How can you tell the difference between an early and late spindle/strut tower?

Easy, early has a pinch bolt, late has a wedge bolt.
So the pinch bolt will be a nut and a bolt at the bottom of the strut that holds the ball joint shaft will be slotted. On the later ones, a wedge bolt looks like a cotter pin with a small nut on the end to tighten it down. No slot at the bottom of the strut.

Thanks! That is a big help, unfortunately I won’t be able to check until next weekend since the car is not stored local to me. I also found another picture on my camera roll showing the caliper I removed has 2 bleed valves. I think this indicates a later caliper (and thus late rotors and struts). Can anyone confirm? I can’t recall if the rotor has the hub ring or not and don’t have a picture at the moment.

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I am guessing the struts were swapped out because those are late ATE fronts. The bottom of the strut will have a nut instead of a bolt.

Yes late. Yes you need to machine the calipers to fit those struts. And yes the rotors I have posted are held for you.