compression ratio

Old 04-18-2009, 06:40 PM
  #1  
gasalley
Member
CRAFTSMAN
Thread Starter
 
Join Date: Feb 2005
Location: Iowa
Posts: 53
Default compression ratio

can anyone tell how to figure compression ratio without taking the heads off?
I have a sbford 302,stock pistons w/.030 overbore, `78 351W heads w/ 202 intake valves, milled(don't know how much). :?
gasalley is offline  
Old 04-19-2009, 06:40 AM
  #2  
JimmySmith
Senior Member
MASTER BUILDER
 
Join Date: Jan 2007
Location: Batesville Ms.
Posts: 167
Default CR

You would have to know what piston and what chamber CC you have to figure this. Later J.Smith 4621 racing
JimmySmith is offline  
Old 04-19-2009, 10:24 AM
  #3  
desoto30
Member
JUNIOR BUILDER
 
Join Date: Feb 2008
Location: Childers Australia
Posts: 98
Default

the only way I'd imagine that this could be done would be to fill the cylinder @ tdc & bdc with fluid & calc from that,though sealing may present a problem
desoto30 is offline  
Old 04-19-2009, 10:49 AM
  #4  
Jordan1984
Member
MASTER JOURNEYMAN
 
Join Date: Feb 2008
Posts: 47
Default

You can buy a compression gauge from an auto parts store that you put in place of the spark plug and bump the engine over. It has a reset on it that locks it in place while you are bumping the engine from the driver seat, or you could have a buddy do it while you watch it. Put it in every cylinder and write it down on paper, then add them all together. Take that number and divide it by the number of cylinders, and you will get a round about compression ratio.
Jordan1984 is offline  
Old 04-19-2009, 12:27 PM
  #5  
MEMRACING62
Senior Member
RACING JUNKIE
 
Join Date: Sep 2007
Location: orland pk il
Posts: 2,399
Default

??? :shock: :shock:
MEMRACING62 is offline  
Old 04-19-2009, 02:52 PM
  #6  
suicidebomb
Senior Member
RACING JUNKIE
 
Join Date: Jul 2007
Location: Independence, Missouri
Posts: 1,181
Default

Originally Posted by MEMRACING62
??? :shock: :shock:
Confused? me too :shock: :?
suicidebomb is offline  
Old 04-19-2009, 02:57 PM
  #7  
MEMRACING62
Senior Member
RACING JUNKIE
 
Join Date: Sep 2007
Location: orland pk il
Posts: 2,399
Default

must some kinda new math!! :lol: :lol:
MEMRACING62 is offline  
Old 04-19-2009, 03:41 PM
  #8  
wrightway
Senior Member
SENIOR BUILDER
 
Join Date: Feb 2005
Location: LAWTON MI
Posts: 113
Default

Originally Posted by Jordan1984
You can buy a compression gauge from an auto parts store that you put in place of the spark plug and bump the engine over. It has a reset on it that locks it in place while you are bumping the engine from the driver seat, or you could have a buddy do it while you watch it. Put it in every cylinder and write it down on paper, then add them all together. Take that number and divide it by the number of cylinders, and you will get a round about compression ratio.

:shock: All that will get you is an average cranking psi :roll:
wrightway is offline  
Old 04-19-2009, 05:15 PM
  #9  
Tod74
Senior Member
RACING JUNKIE
 
Join Date: Sep 2007
Posts: 4,137
Default

Holy Cow My compression ratio is 245 to 1!!!!
Tod74 is offline  
Old 04-19-2009, 05:18 PM
  #10  
BEAST477
Senior Member
RACING JUNKIE
 
BEAST477's Avatar
 
Join Date: Feb 2007
Location: Michigan
Posts: 1,900
Default

Originally Posted by Tod74
Holy Cow My compression ratio is 245 to 1!!!!
WOW Tod, where do you get fuel for that? :shock:
BEAST477 is offline  

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service - Do Not Sell My Personal Information -