Re: [Chevelle-list] Pistons 101
Thanks Bill. I have the How to Rebuild Your Big Block Chevy, and will pick up the other one. Larry - Original Message - From: Bill Lessenberry To: The Chevelle Mailing List Sent: Wednesday, May 25, 2005 3:12 PM Subject: Re: [Chevelle-list] Pistons 101 At 01:48 PM 5/25/2005, you wrote: I'd like to pick your collective brains a bit here...Third QuestionCompression ratio - what is the math behind it? If I had 150psi in a cylinder, would that mean 150 (compression) / 14.7 (ambient pressure) = 10.2 meaning a compression ratio of 10.2:1?CR=the volume of the cylinder, head gasket volume, and combustion chamber volume divided by the volume of the combustion chamberIf you have a 396 then here is the cylinder volume 4.094 (bore)x4.094x.7854 (constant)x 3.76 (stroke)=49.493 cubic inchesAs an example--chamber and gasket volume=111.2 cc (cubic centimeters) 111.2 divided by 16.386 (constant)=6.786 cubic inches49.493 + 6.786 6.786 =8.29:1 Compression ratioBuy a book--this came from How to Hot Rod Big block Chevys. Another is How to Rebuild Your big Block Chevy. Available through big box book stores and Jeg's Summit, et.al.BL
Re: [Chevelle-list] Pistons 101
At 01:48 PM 5/25/2005, you wrote: I'd like to pick your collective brains a bit here... Third Question Compression ratio - what is the math behind it? If I had 150psi in a cylinder, would that mean 150 (compression) / 14.7 (ambient pressure) = 10.2 meaning a compression ratio of 10.2:1? CR=the volume of the cylinder, head gasket volume, and combustion chamber volume divided by the volume of the combustion chamber If you have a 396 then here is the cylinder volume 4.094 (bore)x4.094x.7854 (constant)x 3.76 (stroke)=49.493 cubic inches As an example--chamber and gasket volume=111.2 cc (cubic centimeters) 111.2 divided by 16.386 (constant)=6.786 cubic inches 49.493 + 6.786 6.786 =8.29:1 Compression ratio Buy a book--this came from How to Hot Rod Big block Chevys. Another is How to Rebuild Your big Block Chevy. Available through big box book stores and Jeg's Summit, et.al. BL
[Chevelle-list] Pistons 101
I'd like to pick your collective brains a bit here... First Question - I just started going through my "basket case" 396 that I got with my 66SS. When I was dropping off the block at the machine shop, I noticed at the bottom of each cylinder, there was a stamped 9, 10, or 11. I wondered what that was all about. Then today, as I was wire brushing the tops of my pistons, I noticed either a 9, 10 or 11 stamped on the top of each piston. Can anybody tell me what those numbers mean? Second Question The pistons I have are marked (casting number?) 385624, MASSENA and GM. If I used the oval port heads that came with the block with these domed pistons, what would/should my compression ratio be, and would I have problems with detonation using premium pump gas? Third Question Compression ratio - what is the math behind it? If I had 150psi in a cylinder, would that mean 150 (compression) / 14.7 (ambient pressure) = 10.2 meaning a compression ratio of 10.2:1? Thanks in advance for your help. Larry Shouse
