Quench
From Crankshaft Coalition Wiki
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==Parts stack height== | ==Parts stack height== | ||
| − | When the parts that make up the reciprocating assembly are selected, these parts have to fit into the | + | When the parts that make up the reciprocating assembly are selected, these parts have to fit into the deck height. For a Small Block Chevy (SBC) this value is ~9.025". When calculating the height of the parts that make up the reciprocating assembly, use 1/2 of the stroke, add the rod length, and piston compression height. For a stock 350 SBC, this would be 1.74" + 5.7" + 1.56" = 9.00". If the block is uncut, the decks will be about 9.025". Using a head gasket of 0.015" will give a quench figure of 0.040". If the decks are cut the thickness of the head gasket can be used to compensate as needed. |
In a running engine, the oil clearance will create a slightly longer stack- a 0.003" rod bearing oil clearance will add something slightly less than 0.003". In this article, oil clearance will not be added to the stack height. If desired the oil clearance may be added; easiest way to do this would be to either add the oil clearance to the rod length, or simpler yet, just add the oil clearance after the stack height is calculated. The added height from the oil clearance would only be an issue if the engine is being built with a marginal amount of quench (<0.035" for steel rods); if built with the "ideal" 0.040" quench, the oil clearance can be basically ignored. | In a running engine, the oil clearance will create a slightly longer stack- a 0.003" rod bearing oil clearance will add something slightly less than 0.003". In this article, oil clearance will not be added to the stack height. If desired the oil clearance may be added; easiest way to do this would be to either add the oil clearance to the rod length, or simpler yet, just add the oil clearance after the stack height is calculated. The added height from the oil clearance would only be an issue if the engine is being built with a marginal amount of quench (<0.035" for steel rods); if built with the "ideal" 0.040" quench, the oil clearance can be basically ignored. | ||
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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.empirenet.com/pkelley2/DynamicCR.html Kelly DCR calculator] | *[http://www.empirenet.com/pkelley2/DynamicCR.html Kelly DCR calculator] | ||
| − | *[http://www. | + | *[http://www.uempistons.com/calc.php?action=comp2 KB/Silvolite 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 rtatio 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. | ||
| + | |||
| + | {{Note1}}If the intake valve closing (IVC) point isn't known, it can be calculated: | ||
| + | # Divide the intake duration by 2 | ||
| + | # Add the results to the lobe separation angle (LSA) | ||
| + | # Subtract any ground-in advance | ||
| + | # Subtract 180 | ||
| + | This result does not need to have any amount added to the IVC point, like the KB calculator calls for. | ||
===Static compression ratio=== | ===Static compression ratio=== | ||
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