Confused about Case Through Bolts

[targasc1980]

I'm puzzled about several things regarding the 3.0 case from a 1980 911sc I'm about to put back together. An answer to any of my questions would be appreciated.

Most confusingly, Wayne's book states that there are thirteen cap nuts that attach to the case through bolts and studs. Case disassembly happened hurriedly and unexpectedly after hours at my machinists' shop (not planned, but we had to drill out a broken stud), so I didn't count the cap nuts when we disassembled. However, I only have twelve, and looking at my case, I only see twelve holes. Did the number of these nuts vary through the years?



Next, the case looks to be somewhat damaged, though I don't know of any traumatic events in this engine's life. This first photo is inside the case below where the thermostat lives.



This photo is of the outside of the same passageway, a little further down. This doesn't look normal to me. Or is it? What's going on here?




Additionally, I have an M8 stud lying around that came from somewhere on the case (again, disassembly was hurried). I looked all over the case and can't see anywhere that a stud looks like it is missing. Any ideas on how to figure out where it came from?

My last question is regarding the 22 locking nuts on the outside of the case. According to this website, regular nuts were used here until 1984, when prevailing torque nuts were used. As far as I can tell, the factory never used nyloc nuts here. But the nuts that were on my case were nyloc. Does this mean the case has been split before? Or did the factory use nylon nuts at any point?

Thanks in advance for any help.

[scootergt3]

there are 13. look at the other case half, there will be 11 around the cylinders and 2 behind the oil cooler mount. as for the case perimeter nuts, I've always used nyloc nuts.

also, the so called damage is normal, at least the inside of the case is.

[Flat6pac]

Wire brush and some JBWeld on both exterior places will stop any potential leaks.
Remember, there is a fine thread 10mm nut on the inside of the left chain passage. That's why there is a odd number of cap nuts
Bruce

[SCadaddle]

Oil Leak - Help