Boxerworks.com

Are all center bolts for valve covers on 1000cc airheads the same length and thread pattern?

Appears to be the case. Using the part number 11120023160, it seems to cross many models:

http://www.realoem.com/bmw/enUS/part?id ... 1121744330

Snowbum talks about the acorn nut and threads at the bottom of this page:

http://bmwmotorcycletech.info/pushrodseals.htm

If the stud pulls out, it can be replaced with a longer all thread and loctited in place.

Kurt in S.A.

Thanks Kurt

There's no issue with the nut, it's the studs that are too short. Either replace the studs with longer ones or make sure the the stud fully engages all of the threads in the head and accept whatever threads are left for the nut. Steel in steel can cope with fewer threads better than steel in alloy. I've never put a torque wrench on one but It doesn't need to be much above finger tight, at a guess not more than 5ftlbs. I've never had one come loose at that or leak any oil.

When I pulled that stud on mine I noticed that the threaded portion was longer on one end than the other. I reversed the stud and installed the longer threaded end in the head enough to catch threads and gingerly tightened the other end against the cover.

I've seen photos where the stud hole was drilled on through. Then a steel hex nut was coerced into the open area between the rocker area and combustion chamber. (There's an existing hole at that location in the head.) A longer stud was then threaded into the hex nut so that the valve cover stud is pulling against the steel hex nut.



Not the prettiest repair, but definitely the strongest !

I thought all heads had the centre stud hole drilled though?
I'm running with just a centre nut plus silicone on one head to overcome head warp and oil leak. Leak stopped.

ME 109 wrote: ↑Sat Jun 16, 2018 12:51 am I thought all heads had the centre stud hole drilled though?

I thought so too. That's how I check all the threads are engaged by looking down the gap to see if the end of the stud is flush. As it came from the factory they weren't flush so I double nutted the studs and turned them in a bit.