Regarding the thread I started at ...
http://www.vwdiesel.net/forum/index.php?topic=25119.0... I finally got my XZN socket kit, and have now removed #5 bolt.
So back to the main point of what it is ... 11 or 12mm ... so that I can order the proper set of bolts. In taking it out, the washer is 'partially' seated within the base of the mounting flange on the floor of the head as viewed from the top. Don't know if that is important, but seem to recall something like that mentioned in the earlier thread, so thought would advise.
Here are images of the bolt, with a ruler alongside.
Hopefully those of you that are versed in this can advise which set to order.
looks to be an 11mm bolt to me.
The bolt excluding the head, is 4 1/2 + a bit inches, which is 115mm which is a 12mm bolt.... 
11mm bolts were 98mm allen head.
Interestingly, early gasser bolts were 11mm and 96mm long with star heads. Could some early engines have ended up with those gasser bolts by mistake, leading to the bolt issues of the past?
Moderator please conjoin these 2 threads about threads 
Edit; 'Pipped by Rabbitman'
You measure a socket head bolt from under the head if that helps.
BTW what side of the drafting ruler are you using? It has been a long time and I don't know what I am looking at.
the best way to tell is to go down to the hardware store and see if it will thread into a 12x1.5 nut.
EXCELLENT call truck.
Looks like I forgot to put on the thinking cap this morning.
My '
DUH' account is becoming way overdrawn.
12mm x 1.75 pitch. 1.50 was tried, but hung up about 1/3 of the way on the shaft.
THANKS !!
the best way to tell is to go down to the hardware store and see if it will thread into a 12x1.5 nut.
is it 12x1.75?
I cant remember.
I could look the tap I use to chase the block threads real quick...
-Owen
just looked, and your right 12x1.75
good to hear that you got it figured out!
Wanna know something funny?
12mm head bolt thread is, if I'm not mistaken, the same as your lug bolt thread is the same as the CIS injector thread.
Wanna know something funny?
12mm head bolt thread is, if I'm not mistaken, the same as your lug bolt thread is the same as the CIS injector thread.
is the same as the engine/tranny bolts... perfect use for old head bolts is for bolting engines to an engine stand...lots of threads so you can space the engine back far enough to work on the clutch.
Yep there are 14.25 threads per inch in the picture so M12 x1.75
Wanna know something funny?
12mm head bolt thread is, if I'm not mistaken, the same as your lug bolt thread is the same as the CIS injector thread.
lug nuts/bolts and injector heads are 12x1.5, so they must be different from head bolts..