optimum quench/compression
February 20th, 2013, 10:54 AM
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optimum quench/compression
ok, while i'm not new to engines, or rebuilding them, i am still a bit new to optimal tuning. i'm fairly certain i have got what i need, but looking for opinions on quench vs. compression.
running a .030 over 350, flat top, 4 valve relief, deck height of .012". cam is comp cams xe262 218/224 @ .050, .462/.469 lift, 110 lsa. heads are '810 casting, 65cc, 1.94 valve '93 350 truck heads. yes, swirl port. all stock, no porting. i know these are not ideal heads, but i'm not building a beast. this is a daily driver/cruiser with economy before power. it will see some track time, but i do not expect fast numbers. i already know this. i have no goal for track speeds or times. just something to have fun with.
using various calculators, with a 4.166 bore, .039" compressed thick head gasket, i come in at 9.95:1 scr, 7.69:1 dcr (correct cam specs were input) but a quench of .051", which from what i've read is not optimal. now, if i change things, go with a thinner head gasket, say . 4.130 bore, .028 thick it raises my CR to 10.25:1 but keeps my DCR at 7.912:1 and drops quench to .040, which has been stated to be optimal.
can i get away with pump gas at 10.25:1 CR? for a street/daily driven motor is .040" quench getting too tight? i've heard too tight quench can break things.
running a .030 over 350, flat top, 4 valve relief, deck height of .012". cam is comp cams xe262 218/224 @ .050, .462/.469 lift, 110 lsa. heads are '810 casting, 65cc, 1.94 valve '93 350 truck heads. yes, swirl port. all stock, no porting. i know these are not ideal heads, but i'm not building a beast. this is a daily driver/cruiser with economy before power. it will see some track time, but i do not expect fast numbers. i already know this. i have no goal for track speeds or times. just something to have fun with.
using various calculators, with a 4.166 bore, .039" compressed thick head gasket, i come in at 9.95:1 scr, 7.69:1 dcr (correct cam specs were input) but a quench of .051", which from what i've read is not optimal. now, if i change things, go with a thinner head gasket, say . 4.130 bore, .028 thick it raises my CR to 10.25:1 but keeps my DCR at 7.912:1 and drops quench to .040, which has been stated to be optimal.
can i get away with pump gas at 10.25:1 CR? for a street/daily driven motor is .040" quench getting too tight? i've heard too tight quench can break things.
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