Possibly also the timing was too early causing "hammering".

Entity Maynard Southard spoke thus:
> Rachel:
> I'm not sure how this happened.  If you've seen the head and block apart, it
> appears that at least 1/3 of the prechamber insert is covered by the head
> gasket and the engine block on the other side.  I wouldn't think it could
> wiggle its way loose, unless maybe the head was really not torqued down
> correctly (although I'd think ANY torque would be sufficient to keep it in
> place and thus let the head gasket blow first.)  There was a half-moon shaped
> piece of head gasket missing at this point, so perhaps the head gasket did
> blow
> out this piece first and that gave the insert some room to drop down.  The PO
> had replaced the head gasket at least once prior to my purchase and also
> fiddled with the fuel delivery on the pump.  I'm guessing he had no clue what
> he was doing.
>
> Maynard Southard  OvO '79
> '82 Westy Diesel "Reinhardt"
> '82 Vanagon GL Diesel
> '93 EV GL "Klinger"
> '00 Golf GLS TDI "WooHoo"
> '84 Jetta GL TD "Donor"
>
> On Wednesday, September 05, 2001 10:16 AM, Rachel Cogent [SMTP:Gnarlodious@e
> arthlink.net] wrote:
>>> months ago when the #2 prechamber insert loosened and did a nice tap dance
>>> on
>>> top of the piston.
>> So tell me what causes this to happen? I thought the the combustion chamber
>> was pressed between the block and head so could not come loose.