Henry- very cool picture. Actually I always wondered if domed pistons put more pressure on the compression ring or if it reduces piston slap? Sounds like a design trade-off, yet if alloy technology has forged ahead (sorry for the pun!), I would guess domed piston, hemispherical head is now the ideal setup. Say, wasn't Chrysler proving this concept with its 426 Hemi back in '69?
-George -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] On Behalf Of Henry Bonath Sent: Monday, December 23, 2002 8:20 AM To: George Freeman Cc: 'The Rex list' Subject: Re: CRX: Compression question Well, I'm not sure about how head shaving affects a D-motor as I haven't done it myself... But yeah it would increase the compression ratio due to the smaller combustion chamber... As far as the ZC goes, the compression is high because of the piston dome, I mean, have you ever seen these things? http://www.heeltoeauto.com/dseries/images/PDNtop1.jpg This isn't actually the correct piston, it's from a 98-00 Civic GX but the dome is similar to the ZC. HTH -Henry On Sun, 2002-12-22 at 22:07, George Freeman wrote: > I hear advantages/disadvantages of shaving the head on a D-series > motor. I assume this increases compression due to the slightly smaller > volume available to the cylinder chambers. This in turn increases > horsepower and only slightly increases torque. > > Example: > > D16A6 SOHC 1590cc 105@6000rpm 98@5000rpm 9.1:1cr > ZC DOHC 1590cc 130@6,800rpm 106@5,700rpm 9.5:1cr (is this engine > stroked or is the head different?) > > Granted, the ZC has better cam profiles since there are two cams and > this helps increase power. Overall, doesn't this increase engine heat > and engine wear due to the higher kinetic energy and is it fair to say > higher compression engines wear faster? > > > George > '89 DX-Hybrid-D16Z6, 127k miles > "Seats, Suspension, Engine, MSD, next=heat reduction!" > >
