RE: Z series blocks (Long)

[E Smith]

Title: Message

The stock Z24 gasket is only good for 90mm. The Z24 head gaskets can be modded to suit 92mm bore but they are custom made. They cost around $140 each at last pricing I had, having new larger fire rings fitted to stock gaskets.   For my 10 cents worth: -  the big problem with bores 92mm+, is the available duration of flame burn. At 6000 rpm the time available for the burn is approx 8 milliseconds allowing for cam timing. At 8000 rpm duration is closer to 6 milliseconds. In a 92 mm bore this can mean lowered efficiency at higher engine speeds as the fuel mixture burns at nearly the same velocity regardless of engine speed.   The best way's to increase fuel burn speed are to increase turbulence of the mixture via good port shape and good squish design in chamber (eg ducati and other bike engines that have it down to a fine art through chamber design and port shapes!), as well as good mixture control. Increased compression, better octane fuels and dual ignition sources making multiple flame fronts are all ways to overccome the problem. As a result I think bigger bores are not always better.    Cheers, Feral Errol <http://www.datrats.com.au/> -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Chris Howard Sent: Tuesday, January 14, 2003 7:56 PM To: [EMAIL PROTECTED] Subject: RE: Z series blocks can you get a 92mm head gasket?   Cheers,   Chris --membersozdat------------------------------------------------------- OZDAT Mailing List Please Note:- Send (un)subscribe requests to [EMAIL PROTECTED] Send submissions to [EMAIL PROTECTED] No unauthorised redistribution of this email http://www.ozdat.com/ozdatonline/index.htm http://www.ozdat.com/ozdatonline/listindex.html http://www.mail-archive.com/membersozdat@datascribe.com.au/ ---------------------------------------------------------------------