Mike: The Adapter Nut when using a different M30 head?

[canada karl]

Why is an adapter nut necessary? Why wouldn't the stock 76 530i(motor I have) nut work or the 87 535i(donor head) nut work? Thx CK

[onovakind67]

I recently put an M30B35 long block in my Bavaria, and the adapter nut #11311284801 was necessary because the later cam does not have a slot milled in it to accept the early distributor drive.

[canada karl]

Thanks for the info. I guess I'll have a better picture of the situation once I actually pull the head and get a visual. Thx CK

[Mike W.]

The first pic is what a motronic cam looks like, see how shallow the drive is compared with the broken one in the background? You need more than that to ensure it continues to drive the distributor.



Next is what it looks like installed.



And finally just the nut.



Make more sense now?

[canada karl]

Thanks Mike Now I understand the hex nut function and purpose. What kind of torque is needed for the install and can it be done on the bench provided there is a way to hold the flange while tightening? Karl

[Mike W.]

I think torque spec is about 125 pounds. Use red locktite if you omit the original lockplate. Yeah, sometimes a picture can be worth a thousand words.