Editing Block deck height
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==Deck heights defined== | ==Deck heights defined== | ||
− | + | ask faisal | |
An uncut production SBC block deck height is nominally 9.025". When combining a 0.045" piston deck height with a 0.040" compressed gasket, the result is a 0.085" '''[[quench]]''' distance, which will have little effect in controlling detonation. Quench is recommended at no less than 0.035" to 0.045", so a zero piston deck height with 0.040" gasket puts the squish in the right place (0.040"). This isn't the only way a 0.040" quench can be reached, obviously. A better way (and cheaper from the machine shop labor standpoint) is to use a thinner head gasket and keeping the deck as thick as possible. This is easy to do with the 4" nominal bore SBC because of the abundance of '''[[head gasket]]s''' available for that engine. | An uncut production SBC block deck height is nominally 9.025". When combining a 0.045" piston deck height with a 0.040" compressed gasket, the result is a 0.085" '''[[quench]]''' distance, which will have little effect in controlling detonation. Quench is recommended at no less than 0.035" to 0.045", so a zero piston deck height with 0.040" gasket puts the squish in the right place (0.040"). This isn't the only way a 0.040" quench can be reached, obviously. A better way (and cheaper from the machine shop labor standpoint) is to use a thinner head gasket and keeping the deck as thick as possible. This is easy to do with the 4" nominal bore SBC because of the abundance of '''[[head gasket]]s''' available for that engine. | ||
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*[http://www.wallaceracing.com/dynamic-cr.php Wallace Racing DCR calculator] | *[http://www.wallaceracing.com/dynamic-cr.php Wallace Racing DCR calculator] | ||
*[http://www.rbracing-rsr.com/comprAdvHD.htm RSR DCR calculator] | *[http://www.rbracing-rsr.com/comprAdvHD.htm RSR DCR calculator] | ||
− | {{Note1}} Some dynamic compression ratio calculators (like KBs) ask for an additional 15 degrees of duration be added to the IVC @ 0.050" lift point figure. <br> | + | {{Note1}} Some dynamic compression ratio calculators (like KBs) ask for an additional 15 degrees of duration be added to the IVC @ 0.050" lift point figure. This works OK on older, slower ramped cam lobes, but the faster lobe profiles may need to have 25 degrees or more added to be accurate.<br> |
{{Note1}}If the intake valve closing (IVC) point isn't known, it can be calculated: | {{Note1}}If the intake valve closing (IVC) point isn't known, it can be calculated: |