what is supposed to be here?

[triiodide]

http://www.realoem.com/bmw/diagrams/a/k/4.png
I had blown a head gasket and did not pay enough attention when taking it apart, either that or the 3 months has fuzzed my memory. The number 8 piece, the stud. i have two on the head and the top center does not have a stud. am i missing a stud? or is it a bolt? and i cant for the life of me remember what goes there. i have yet to put the head back on the car because i want everything accounted for and ready for all new gaskets.

[Blaise]

Well, I cannot tell you what it is for, but I can show you what it looks like assembled.

Here it is in my stock 1977 530i. Nothing was mounted to those two bolts.



A closer shot.



Now here it is on my M30B34M motor. It was blanked off when the motor was rebuilt, as it is not used on the E12. Again, sorry that I cannot tell you what it would do in an E28 or the like.



Hope this helps

[triiodide]

thanks. I have a 1980 528i, and i was fairly sure there was nothing there, but when i gave the head to my machinist, there were a few things left on it that i was given back in a box and i had an extra bolt for that hole.

[faris]

Does anyone know the b28 conrod length? I've read 135mm for the b35, are all m30 con rods the same length? I'm also reading that the m88/s38 rods are 144mm.

[Peter Florance]

Does anyone know the b28 conrod length? I've read 135mm for the b35, are all m30 con rods the same length? I'm also reading that the m88/s38 rods are 144mm.

I thought all M30 rods were same length and that pistons had different wrist pin heights to accommodate different stroke setups.

[Mike W.]

I don't know the length offhand, but all M30 rods are the same length. And not interchangeable with S38 engines even with that engines heritage.

[Falkenberg]

Even a lot of M10 rods are the same.

I am not sure about the old 3.3 engine, at least the part number is different. That engine I think has bore - stroke 89 × 88. Very strange.

[Robert Bondi]

That raised boss region where #8 (stud) is going is basically a legacy
in the casting for mounting a mechanical fuel pump on the early M30s.
If that hole is blind (does not penetrate cyl head wall), you could just leave
it. Otherwise, use a short bolt and seal it up. Our cyl head FAQ might say a little more on that.

http://www.realoem.com/bmw/diagrams/a/k/4.png
I had blown a head gasket and did not pay enough attention when taking it apart, either that or the 3 months has fuzzed my memory. The number 8 piece, the stud. i have two on the head and the top center does not have a stud. am i missing a stud? or is it a bolt? and i cant for the life of me remember what goes there. i have yet to put the head back on the car because i want everything accounted for and ready for all new gaskets.