64cc heads on 6.0 motor. compression ratio?
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i'm coming up with 11.34:1 with .045 head gaskets and assuming you are using a flat top piston. also with the piston out of the hole about 11 thou.
i'm not sure what the piston out of the hole is, but I think it varies a little from motor to motor. Hope this helps.
edit: using the same formula with .050 gaskets and .007 piston out of the hole your looking at 11.23:1
Here is what I used:
CR = (SV + CV) / CV
where:
CR = compression ratio
SV = Swept Volume (displacement of one cylinder)
CV = Compressed Volume (volume at piston TDC)
To get the swept volume of one cylinder in CCs, the handy formula is:
bore x bore x stroke x 12.8704
For a stock short block, this works out:
3.90 x 3.90 x 3.62 x 12.8704 = 709 CC (rounded up)
Compressed volume is the sum of chamber volume, deck volume, gasket volume, and piston dish volume (including valve reliefs). For a stock LS1:
Chamber volume = 66.67
Deck volume = 3.9 x 3.9 x 12.8704 x (-.006) = -1.17 CC (negative because piston out of hole)
Gasket volume = 3.9 x 3.9 x 12.8704 x .060 = 11.7 CC (guessing on the gasket bore?)
Piston dish volume = 0 (true flat top piston)
Thus CV = 66.67 + 11.7 - 1.17 = 77.2 CC
Put all of this into the first formula:
CR = (709 + 77.2) / 77.2 = 10.18
i'm not sure what the piston out of the hole is, but I think it varies a little from motor to motor. Hope this helps.
edit: using the same formula with .050 gaskets and .007 piston out of the hole your looking at 11.23:1
Here is what I used:
CR = (SV + CV) / CV
where:
CR = compression ratio
SV = Swept Volume (displacement of one cylinder)
CV = Compressed Volume (volume at piston TDC)
To get the swept volume of one cylinder in CCs, the handy formula is:
bore x bore x stroke x 12.8704
For a stock short block, this works out:
3.90 x 3.90 x 3.62 x 12.8704 = 709 CC (rounded up)
Compressed volume is the sum of chamber volume, deck volume, gasket volume, and piston dish volume (including valve reliefs). For a stock LS1:
Chamber volume = 66.67
Deck volume = 3.9 x 3.9 x 12.8704 x (-.006) = -1.17 CC (negative because piston out of hole)
Gasket volume = 3.9 x 3.9 x 12.8704 x .060 = 11.7 CC (guessing on the gasket bore?)
Piston dish volume = 0 (true flat top piston)
Thus CV = 66.67 + 11.7 - 1.17 = 77.2 CC
Put all of this into the first formula:
CR = (709 + 77.2) / 77.2 = 10.18
Last edited by Taspeed; 04-25-2005 at 09:45 AM.