Can someone verify my CR calculation?
08-29-2014, 10:51 AM
#1
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Can someone verify my CR calculation? I have a 404 ls2 and I thought the CR was 11.5, I've used a few calculators and got different results. The calculator going around this site says 11.16/1, can someone double check my numbers and final calculation?
These are the measurements I believe:
Bore: 4.010
Stroke: 4.000
Rod Length: 6.125
Piston comp height: 1.105 (Mahle power pack)
Piston: -4 cc (thought these were -2cc but Mahle said the ones I have are -4cc)
Head combustion chamber: 64 cc (l92 heads milled .036)
Head gasket thickness: 0.055 (stock mls head gasket)
Block deck height: 9.24 (I believe)
These are the measurements I believe:
Bore: 4.010
Stroke: 4.000
Rod Length: 6.125
Piston comp height: 1.105 (Mahle power pack)
Piston: -4 cc (thought these were -2cc but Mahle said the ones I have are -4cc)
Head combustion chamber: 64 cc (l92 heads milled .036)
Head gasket thickness: 0.055 (stock mls head gasket)
Block deck height: 9.24 (I believe)
08-29-2014, 12:52 PM
#2
I come up with 11.5 also, although I don't know the gasket bore of your gasket or the piston deck clearance. This is what I need for SCR:
Chamber: 64cc
Gasket compressed thickness: .055"
Gasket bore: ?
Piston to deck clearance: ?
Deck height: 9.24"?
Stroke: 4.00"
Bore: 4.01"
Rod: 6.125"
If you want to add in the crevice volume (normally not included), include the top ring land height and the piston-to-wall clearance also.
If the block hasn't been milled then the block height should be 9.24, with a 6.125 rod and 4.00 stroke, you'd need the block height to be 9.23 for the compression height to be 1.105. Perhaps the piston deck height is 9.23, the block height is 9.24, and indicates your piston is ~0.010 below the deck?
Chamber: 64cc
Gasket compressed thickness: .055"
Gasket bore: ?
Piston to deck clearance: ?
Deck height: 9.24"?
Stroke: 4.00"
Bore: 4.01"
Rod: 6.125"
If you want to add in the crevice volume (normally not included), include the top ring land height and the piston-to-wall clearance also.
If the block hasn't been milled then the block height should be 9.24, with a 6.125 rod and 4.00 stroke, you'd need the block height to be 9.23 for the compression height to be 1.105. Perhaps the piston deck height is 9.23, the block height is 9.24, and indicates your piston is ~0.010 below the deck?
