Re: Maximum CR closed chamber w2 heads 0.040 quench- pump gas
[Re: ahy]
#2512147
06/23/18 01:09 PM
06/23/18 01:09 PM
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Joined: Jan 2003
Posts: 1,793 Windsor, ON, Canada
Diplomat360
top fuel
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top fuel
Joined: Jan 2003
Posts: 1,793
Windsor, ON, Canada
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...With iron heads (even with decent quench) suggest you shoot for 9.5 CR max.... I have to disagree with this comment. Not sure if you meant it to be specific to the OP's combination, but if meant as a general rule it is not the case, too much depends on cam timing events, etc. Case in point, I have a 360 motor, heavily worked factory iron heads - open chamber (596 casting), thus terrible quench LOL as in -0.015 deck height and a good 0.090" of the open chamber on top of it. But my static CR is blueprinted at 10.6:1, yet the motor runs with NO ping using a very fast ignition advance curve on a pump 94 octane gas. The cam in my case is: Hughes HE3844AL hydraulic flat tappet, 238/244 @ 0.050 on 108LSA.
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Re: Maximum CR closed chamber w2 heads 0.040 quench- pump gas
[Re: domingo]
#2512186
06/23/18 02:37 PM
06/23/18 02:37 PM
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Joined: Jan 2003
Posts: 8,079 Tulsa OK
Bad340fish
master
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master
Joined: Jan 2003
Posts: 8,079
Tulsa OK
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I ran a 340 with good quench at 10:1 with X heads, it had 212psi of cranking compression and ran great on 91 or 93 with 35* total timing. Its first few years of life it had a stock torque converter and It never showed signs of pinging. I was in high school when I had this motor so it never saw much time off wide open throttle lol.
68 Barracuda Formula S 340
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Re: Maximum CR closed chamber w2 heads 0.040 quench- pump gas
[Re: domingo]
#2512842
06/25/18 12:52 AM
06/25/18 12:52 AM
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Joined: Jan 2003
Posts: 9,672 Lima, Peru
domingo
OP
EL Master
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OP
EL Master
Joined: Jan 2003
Posts: 9,672
Lima, Peru
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LETS KEEP THE REPLY TO MY QUESTION SIMPLE- I SAID: for the record.....
I run 9.4:1 on a 440.6 pack with open chamber cast iron heads.
it has a small comp hyd flat tappet cam 224° @ 050 LSA 110° .470 lift
Engine runs great with our 98 octane but its right there on the edge of pinging. It will not tolerate 97 octane gas (which we also have at the pump) or it will start to ping.
I guess thats about as high as I want to go with no quench and a small cam on a cast iron headed motor. Its what I have tested with our gas.
THATS ON A E BODY IN FULL STREET TRIM, 4 SPEED AND 3.54 GEARS. LIKE I SAY THE ABOVE ENGINE RUNS GREAT WITH NO PINGING, BUT WHEN I FILL IT WITH GAS JUST 1 POINT LOWER IN OCTANE,IT PINGS. SO THAT ENGINE IS RIGHT AT THE EDGE OF THE PING ZONE. LETS SAY I SWAPPED HEADS ON THAT ENGINE FOR CLOSED CHAMBER IRON HEADS AND ALL ELSE REMAINED THE SAME. HOW MUCH MORE COMPRESSION WOULD PROPER QUENCH ALLOW ME TO RUN VS. THE 9,4:1 CR WITH NO QUENCH AND OPEN CHAMBER HEADS?
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Re: Maximum CR closed chamber w2 heads 0.040 quench- pump gas
[Re: domingo]
#2514050
06/27/18 06:14 PM
06/27/18 06:14 PM
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Joined: Jan 2003
Posts: 3,575 The Netherlands
BigBlockMopar
master
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master
Joined: Jan 2003
Posts: 3,575
The Netherlands
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I'm daily driving a 360ci with 11.3:1 cr, 0.029-0.030" quench height and a CompCams XE256h with solid lifters. Maybe try Propane as fuel
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