DeTomaso Mailing List: February 98, Message #158
     



From: 	"Ted A. Mitchell" <tmitch@gte.net>

Subject: Re: '71 Pistons - Reply

Date: 	Tue, 3 Feb 1998 17:16:10 +0000



It depends on the type of dished pistons.  If they have a flat top section

that will match up to the quench areas of the heads, they MAY do some good.

The common dished pistons don't have enough.



I had some special J&E pistons made for Vader's supercharged engine, which

matched the combustion chamber of the closed heads.  This allowed me to get

down to 9:1 CR (with a little unshrouding of the valves), and still run 6 to

10 psi boost pressure on pump gasoline with NO detonation.  J&E has the

pattern for these pistons.  This shows the advantage of the quench heads.

Most of the supercharged engines had to go down to 7:1 with open chamber

heads to prevent detonation.



Ted (Vader) Mitchell

http://home1.gte.net/tmitch/pe.htm

http://home1.gte.net/tmitch/chpie.htm

http://home1.gte.net/tmitch/index.htm

-----Original Message-----

From: Dan Jones <djones2@mdc.com>

To: Multiple recipients of list <detomaso@realbig.com>

Date: Tuesday, February 03, 1998 1:12 PM

Subject: Re: '71 Pistons - Reply





>

>> You can vary combustion ratio with with deck height, but closed

combustion

>> chamber heads to piston clearance should never be more than .040, or

>you

>> might as well be using open chambers.  I recommend 0 deck height with

>a

>> compressed gasket of 0.29 approximately - NOT FOR over 7000 rpm.

>

>I assume the above applies to flat top pistons.  What happens when you

>use

>dished pistons?  Does the quench effect still apply?

>

>Thanks,

>Dan Jones

>