Help identify head bolt size: 11mm or 12mm

[overdrivegear]

First off, I've used the search in the forums to help me identify what size of head bolts I need but I couldn't find anything definitive so here is what I have:

CR code 1.6 NA out of an 81 Rabbit
Head part number 068 103 373 B (mechanical lifter)
Block says 1.6D (and not just 1.6)

The engine doesn't have any existing head bolts for me to measure unfortunately.  What do you all think?

[CRSMP5]

you need to tap the bolt holes in the block.. so buy both 11 and 12 tap return the one that does not fit... and then you know the size... wish i could think of the pitch for you...

[ORCoaster]

I have 11 mm on the head and block I am currently rebuilding.  I thought I had the 12 mm ones and even bought those type of bolts.  But after I got the valve cover off I found those 10mm hex heads looking up at me and knew I would be returning 10 bolts to the  store at some point in time. 

My car was built in August of 81 so early on in the production cycle.  Tag on the door would tell you if yours is early like mine and thus likely to be 11 mm bolts.

[R.O.R-2.0]

First off, I've used the search in the forums to help me identify what size of head bolts I need but I couldn't find anything definitive so here is what I have:

CR code 1.6 NA out of an 81 Rabbit
Head part number 068 103 373 B (mechanical lifter)
Block says 1.6D (and not just 1.6)

The engine doesn't have any existing head bolts for me to measure unfortunately.  What do you all think?

try screwing a gasser bolt in the block. if it fits, its 11mm, if its LOOSE, its 12mm.

MOST of the CR engines ive seen, were of the 11mm variety..

CK was the 1.5D, and CR was the next one to come out. one of the first 1.6Ds IIRC.

[rs899]

I would guess 11mm.  Can't you tell from the holes in the head?  From the head part # ( ending in "B", meaning early rev) I would say 11mm, too

[DRP67207]

I'm not sure if this is the case with all heads, but on the two that I've just been dealing with, the 12mm head has bumps on the back (manifolds) side to provide clearance for where the bolts and washers seat, while the 11mm one just goes straight down from top rim where the valve cover sits.

[R.O.R-2.0]

you need to tap the bolt holes in the block.. so buy both 11 and 12 tap return the one that does not fit... and then you know the size... wish i could think of the pitch for you...

the 11mm bolts are a goofy, non-standard thread pitch.. i know that for certain.

[theman53]

I would guess 11mm.  Can't you tell from the holes in the head?  From the head part # ( ending in "B", meaning early rev) I would say 11mm, too

The casting letters and numbers that are on the heads mean absolutely nothing in identifying them. The mech and hydro heads came with all the same part numbers and such. I had a turbo head that was an F and mech and I had a hydro head that was N/A with the F at the end. I really wish they would have had a standard like a SBC, but they didn't.

[bajacalal]

Is it just me because I thought the 11mm bolts have hex heads while the 12mm bolts have triple square (12 point) heads?
 

[theman53]

Is it just me because I thought the 11mm bolts have hex heads while the 12mm bolts have triple square (12 point) heads?
 

Usually, but IIRC someone could put gasser stretch bolts in that are the triple square but 11mm. Lots can happen in 30 years.

[libbydiesel]

That's also not relevant to this situation where the engine didn't come with any bolts for him to look at.

[R.O.R-2.0]

I'm not sure if this is the case with all heads, but on the two that I've just been dealing with, the 12mm head has bumps on the back (manifolds) side to provide clearance for where the bolts and washers seat, while the 11mm one just goes straight down from top rim where the valve cover sits.

sorry, but that statement is not true.

i just went and looked at all my old spare heads. ive got 1.5D, 11mm 1.6, and 12mm 1.6/TD heads...

ALL OF THEM HAVE THE BUMPS. even my 86 GTI has bumps on the back of the head..

they have ALWAYS had the bumps at the head bolt bosses..

[DRP67207]

Well then I have an anomaly of some sort, 'cause i just put an 11mm head on my engine that has no bumps.  Has the VW markings on it, says Germany on the front, number on the left is 068.103.373 B.  Anyone else seen this before?

[R.O.R-2.0]

Well then I have an anomaly of some sort, 'cause i just put an 11mm head on my engine that has no bumps.  Has the VW markings on it, says Germany on the front, number on the left is 068.103.373 B.  Anyone else seen this before?

all my heads are german as well, and ALL of them have bumps..

i figured if the ancient 1.5D got the bumps, then they all did, or atleast most of them.

[DRP67207]

Has anyone else seen this before? I'm just curious how out of the ordinary these bumpless heads are.  Came out of an '81 caddy I parted out, I believe it was the original engine, but can't be sure.