Is it possible to tell 11mm from 12mm head ... if not off engine ?????

[truckinwagen]

that looks like an 11mm head to me(but others will confirm that if so)

the head bolts(the ones with oil in the tops) look like they are allen headed from here, and they do not appear to be recessed into the head the way that a 12mm head would be.

so I will give a tentative, "thats an 11mm head"

-Owen

[doonboggle]

I just took some tissue and soaked up the oil.
Now see a 12 indent (recessed) socket hole.

Using my torx set I find that the 12955 one, with 6 indents, fits ... meaning it is a recessed head.

The '12' in the size number is common to the whole set, so am sure it does not indicate the head as a 12mm one.

Hope someone knows more about conversion for this socket than I do.

that looks like an 11mm head to me(but others will confirm that if so)

the head bolts(the ones with oil in the tops) look like they are allen headed from here, and they do not appear to be recessed into the head the way that a 12mm head would be.

so I will give a tentative, "thats an 11mm head"

-Owen

[truckinwagen]

ok, so with triple square bolt heads, it can either an 11 or a 12mm head(as there are triple square 11mm head bolts as well as 12)

it still looks like the bolt heads are sitting proud enough to indicate that it is an 11mm and not a 12.

but again, others will chime in soon too.

[theman53]

What size triple square are the 11mm triple square? Sucks if they are the same. I have no clue what head it is now, but I will say 12mm just cause of the triple squares and andrew saying not many 11mm blocks in that line. Are you going to pull the head and tell us?

The other nuts you are talking about just hold the cam caps down...don't remove them.

[Rabbit on Roids]

triple square 11mm bolts are the same size head, and take the same tool  

[VW Smokr]

Have valve cover off.  Here is image...

In the pic it looks like 12mm 'triple-square' bolts (real name of this bolt type is "XZN") and the (mid-'81-on) large central oil drain hole to me... just as Andrew mentioned. By end of '81, most all 'new' VW diesels here in Can/US had 12mm "stretch" bolts.

IIRC diesel Vanagons weren't sold here until late 1982. Obviously someone did a bit of parts swapping to even mount that "CS" in your Caddy: oil pan, pump pickup, engine mounts, maybe pump swap, etc.

J.R.
SoCal

[rabbitman]

I just took some tissue and soaked up the oil.
Now see a 12 indent (recessed) socket hole.

Using my torx set I find that the 12955 one, with 6 indents, fits ... meaning it is a recessed head.

The '12' in the size number is common to the whole set, so am sure it does not indicate the head as a 12mm one.

Hope someone knows more about conversion for this socket than I do.

That "55" in your tool number would mean it's a  T55, it's what I used when I put my head back on. I DON'T recommend using it though, I rounded one head bolt out doing the last 1/4 turn and I ain't looking forward to trying to undo it.

As ROR said though that doesn't tell you what you got, afaik the only way to know is to pull a bolt out and measure it.

[truckinwagen]

ok, here we go.

the 12mm head has pockets machined in the casting so the bolts sit lower in the head, you can see that in this pic


look at the center front bolt hole, see how it is cut down into the head casting?
the washer will sit below the lip machined into the casting.

the 11mm heads do not have the bolt holes machined deeper like this, so the washer and bolt head will sit on top of the casting.

the pic you posted looks like the washer is sitting on top of the casting, not in a pocket machined in it.

so I believe that you have an 11mm head that had gasser head bolts installed in it during a rebuild(which would account for the triple square bolt heads)

[doonboggle]

Sorry fellows, but I am lost by all the comments.  I am a total novice to this and have never removed an engine head, let alone just one of the bolts.

What I understand is this is an unknown head relative to the bolts.  I've tried to identify them as best I can; 12 point that a T55 (6-point) TORX socket fits into.  Came across a metric web page that indicates a T55 TORX is 11.22mm.

Don't know if that clears it up any.

In any case, if the only sure way to ascertain is to pull one of the bolts out, I need some guidance.  I really need to know this so that I can advise the fellow who has offered a head to me, for free, which version I need.  He has several heads for choosing.

My questions are ...

First, to be upfront, I have never removed a head, or even a head bolt. 
If I remove one to ascertain if it is 11 or 12mm, is it a matter of simply backing it out? 
Once identified, can I simply reinstall it?

Secondly, what should I use to remove it, if the 6-point TORX is not a good idea ... keeping in mind that the recessed head has the 12-point indents?

Last, if I do this, will it harm or screw up anything in the rest of the engine by just taking it out for identifying?

At this stage the only thing I feel comfortable with is having identified it as a mechanical lifter version, out of a 1982 Vanwagon.

[theman53]

That "55" in your tool number would mean it's a  T55, it's what I used when I put my head back on. I DON'T recommend using it though, I rounded one head bolt out doing the last 1/4 turn and I ain't looking forward to trying to undo it.

Air Chisel...ask me how I know

Back to the bolt question. I wouldn't use the torx for the reason above. Use this style
and they can be ordered from napa or any tool van, but are here too http://www.google.com/products?q=12mm+triple+square&rls=com.microsoft:en-us&oe=UTF-8&um=1&ie=UTF-8&ei=6NC9S7GgH4H88AbtlujNCA&sa=X&oi=product_result_group&ct=title&resnum=4&ved=0CCMQrQQwAw

I have heard of people that took one out and put it back in, but have only done it on the one that I had to take out with an air chisel.

[doonboggle]

Unfortunately my little camera does not take a good usable close up, so will try to respond as best I can.

If I understand correctly, sounds like the bolt heads of your head are recessed 'possibly' down into the mounting hole areas.  In looking at mine, they 'appear' to be fully exposed and, not having removed one yet, 'seems' to have a slight over-sized thick washer beneath the head.  Thusly, sounds ... based on your analysis ... that it is a 11mm version .

But understanding that it is critical, I recognize that the only way to tell is to remove a bolt for inspection.  So looks like I'm gonna go to our local NAPA or KRAGEN to see if I can get a 12-point ('triple square') socket that will fit. 

I posted last nite this, so will re-ask somewhat differently.

If I remove #5 bolt, will that screw up anything by not being in numerical sequence.  Read in Bentley that, during re-install, to follow a prescribed number sequence.

Then, to restate last posting, in removing this bolt, am I loosening something inside the engine that will 'drop' down, etc.?

Thanks for all the help EVERYONE !!! 
Am embarrassed to be so stupid among all this knowledge.

ok, here we go.

the 12mm head has pockets machined in the casting so the bolts sit lower in the head, you can see that in this pic


look at the center front bolt hole, see how it is cut down into the head casting?
the washer will sit below the lip machined into the casting.

the 11mm heads do not have the bolt holes machined deeper like this, so the washer and bolt head will sit on top of the casting.

the pic you posted looks like the washer is sitting on top of the casting, not in a pocket machined in it.

so I believe that you have an 11mm head that had gasser head bolts installed in it during a rebuild(which would account for the triple square bolt heads)

[doonboggle]

Well ... just returned from Kragen and NAPA ... with nothing in hand to  remove the bolt.
So 'back to the drawing board'.....

What do the rest of you fellows use to remove the bolts?

But understanding that it is critical, I recognize that the only way to tell is to remove a bolt for inspection.  So looks like I'm gonna go to our local NAPA or KRAGEN to see if I can get a 12-point ('triple square') socket that will fit.  

[doonboggle]

NOPE! 

Just came from there. 
The 'manager' did not even understand what I needed ... and had to take my TORX T55 to show him the similarity.

Neither did NAPA ... and same 'dumb' in-store staff.
Neither did Carquest; same story.

Even emailed their customer support link yesterday and asked a question about the TORX set ... by brand name ... I bought recently. 
The fellow responded ... "We don't carry that brand." ... yet, no more than 3 months ago, I bought the set for 67.00 ... & even as recent as today, visited their display wall where the parts were well mounted.

I thought there was a business decline in America these days. 
Seems not for the autoparts stores.

Go figure....

Kragen, Shucks, Checker, O'Reiley's, etc... all carry the Power Built brand and typically have the tripe-square set on the shelf.

[theman53]

http://www.google.com/products?q=12mm+triple+square&rls=com.microsoft:en-us&oe=UTF-8&um=1&ie=UTF-8&ei=6NC9S7GgH4H88AbtlujNCA&sa=X&oi=product_result_group&ct=title&resnum=4&ved=0CCMQrQQwAw

you could pay shipping and get it fast...the second ones down are only $4

[8v-of-fury]

so after all this have we confirmed that 11mm sit above the head surface where as 12mm are recessed in to it? all 11mm and 12mm? or only select few?