[Diy_efi] Timing table change needed with CR increase?

[Mark Riley]

Better check with a piston company, flat tops in a 3.8 will put you well
over 12:1. I think if I remember right, that the Buick chambers are only
like 43 or 48 cc. Even with the open chamber they are fairly resistant to
spark knock at reasonable timing levels. They don't need as much timing as
say a 23 degree small block Chevrolet.

I haven't seen any valve clearance issues with lifts up to .530" in a turbo
3.8 with 24cc dish pistons. That puts it around 8.5:1 compression. 

Mark Riley

-----Original Message-----
From: diy_efi-bounces at diy-efi.org [mailto:diy_efi-bounces at diy-efi.org] On
Behalf Of Steven P. Donegan
Sent: Monday, January 29, 2007 11:13 PM
To: diy_efi at diy-efi.org
Subject: Re: [Diy_efi] Timing table change needed with CR increase?

Although absolutely dead-on advice (on ANY rebuild check ALL clearances)
I kind of doubt a smog 8.5:1 motor with the cam likely to have shipped
with that motor will have any issues with valve pocketless (flat top)
pistons of stock deck height.