How to determine notches regarding head gasket type

[monst]

I looked at my gasket

 and it is not notches.......
 there are three circular holes.

Any thoughts?

[ORCoaster]

I goes by magic numbers more than notch, yours equates to a 3 notch then.

[vwsb1974]

dose it make that big of a difference? I am just wondering cause my car had a 3 hole on it so that is what I put back on.

[TylerDurden]

The number is important... Too thin and pistons hit stuff. Too thick and you sacrifice compression.

[745 turbogreasel]

Holes = metal head gasket = probably not original on IDI?
It is also not common to fail, so you will want to pressure test head as well.

[monst]

So you think my head gasket was replaced once already?
Due to holes... not notches.......    "buenos notches.. "

[745 turbogreasel]

It is almost inconceivable to me that there is an IDI still running with the original  headgasket, so yes.
I'm not sure if any of the 1.6 cars  left the factory with a metal gasket, I've certainly never seen one.

[monst]

Metal?
where is the gasket metal?

Mine is metal.. not sure what you mean by metal???

OEM'

[monst]

OEM's not metal?
What were/are they?

[8v-of-fury!]

They were OEM on 1.9L AAZ engines..

Google man, try it out it works wonders.

[745 turbogreasel]

AAZ is a rare bird in these parts, and bros sig implies a 1.6.

Some engines use a fiber gasket with a few metal rings, and notches to indicate thickness.  Newer ones use a multi layer steel gasket with a viton coating and holes to indicate thickness.

[libbydiesel]

The number is important... Too thin and pistons hit stuff. Too thick and you sacrifice compression.

The compression difference is not really of issue.  The other two factors are 'squish and quench'.  Squish establishes the correct turbulence, again probably not an issue on a pre-chamber diesel.  Of particular issue, tho, in a TD is quench where a significant amount of heat is transferred from the piston crown to the more cooled cylinder head.  Increasing the space between piston crown and head at TDC will have negatively affect quench and cause the piston crowns to run hotter.

[vwsb1974]

That is more of what I was asking. I know to you need to chave the clearence for the piston to head but I was just wondering what the performance implications would be of running a three whan you should be running a 1 or 2 if any.

[745 turbogreasel]

slower, harder to start and less efficient, more polluting and hotter pistons, with possible added safety margin against lifting the head if you are  running 3x factory boost level?

[TylerDurden]

The number is important... Too thin and pistons hit stuff. Too thick and you sacrifice compression.

The compression difference is not really of issue.  The other two factors are 'squish and quench'.  Squish establishes the correct turbulence, again probably not an issue on a pre-chamber diesel.  Of particular issue, tho, in a TD is quench where a significant amount of heat is transferred from the piston crown to the more cooled cylinder head.  Increasing the space between piston crown and head at TDC will have negatively affect quench and cause the piston crowns to run hotter.

Right.... 

cylinder head gaskets are available in thickness of 1.4 to 1.6 mm - to selectively match with engine components to maintain the compression ratio.

W. Brandstetter and R. Dziggel
Volkswagenwerk AG
Wolfsburg

http://www.4crawler.com/Diesel/SAE/vwtdsae.shtml