What shot causes head lifting
03-10-2005, 08:23 AM
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What shot causes head lifting With around 11.5 to 12 -1 compression what shot will cause head lifting problems? With a direct port or one nozzle setup? What point do you need to consider AFR heads?
This is assuming optimal fuel and timing on a 408 inch iron motor.
This is assuming optimal fuel and timing on a 408 inch iron motor.
03-10-2005, 09:43 AM
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The big thing that causes head lifting is Cylinder Pressure, Which timing has a great deal to do with the pressures, also your cam design has a good bit to do with your cylinder pressures. The Afr heads would just allow you to get away with more timing.
For example A buddies engine I designed for him:
408 ci Ls1 Iron Block
Solid Roller
15 to 1 compression
241 heads
Arp L19 Head Studs
Cometic Gaskets
We started playing with it on the dyno last week with 300 worth of bottle, and no headgasket or headlifting problems. Tonight it goes back with 400 worth of bottle. These runs were made on C16 (118 octane) gas and 16 degrees of timing.
For example A buddies engine I designed for him:
408 ci Ls1 Iron Block
Solid Roller
15 to 1 compression
241 heads
Arp L19 Head Studs
Cometic Gaskets
We started playing with it on the dyno last week with 300 worth of bottle, and no headgasket or headlifting problems. Tonight it goes back with 400 worth of bottle. These runs were made on C16 (118 octane) gas and 16 degrees of timing.
03-10-2005, 10:04 AM
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How about with a cam around 270/278 766"/755" on a 110lsa and 106 icl? This will be a setup designed to work every well n/a and pretty good on the jug. This cam is just a rough idea as well. I would like to spray around a 250 to 300 shot to get in the high high 8s.
03-10-2005, 10:09 AM
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Originally Posted by BTL FED
For example A buddies engine I designed for him:
408 ci Ls1 Iron Block
Solid Roller
15 to 1 compression
241 heads
Arp L19 Head Studs
Cometic Gaskets
We started playing with it on the dyno last week with 300 worth of bottle, and no headgasket or headlifting problems. Tonight it goes back with 400 worth of bottle. These runs were made on C16 (118 octane) gas and 16 degrees of timing.
408 ci Ls1 Iron Block
Solid Roller
15 to 1 compression
241 heads
Arp L19 Head Studs
Cometic Gaskets
We started playing with it on the dyno last week with 300 worth of bottle, and no headgasket or headlifting problems. Tonight it goes back with 400 worth of bottle. These runs were made on C16 (118 octane) gas and 16 degrees of timing.
That's insane! In an awesome way.
Josh
03-10-2005, 10:16 AM
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LS1 heads, using stock or upgraded gaskets and studs, are notorious for low clamping force, distortion, lifting, coolant leakage, etc. It is difficult or impossible to predict at what boost or shot this will happen, but I can tell you they have failed under 9 lbs boost and 100 shot with ARP studs. We changed to 9/16" studs torqued to 140 lbs, SCE .050 copper gaskets, O-rings and receiver grooves and lifting stopped.
03-10-2005, 10:23 AM
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Originally Posted by DAPSUPRSLO
How about with a cam around 270/278 766"/755" on a 110lsa and 106 icl? This will be a setup designed to work every well n/a and pretty good on the jug. This cam is just a rough idea as well. I would like to spray around a 250 to 300 shot to get in the high high 8s.
03-10-2005, 10:40 AM
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What do you guys think about mechanical timing like a cam with a 114lsa but with +4 ground into the cam. What are the pros and cons of this? I am in the midst of setting up a new motor with a 300 shot and wondering were I should set the cam timing.
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03-10-2005, 11:02 AM
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Originally Posted by BTL FED
That cam has a little more overlap than I would want to see on that big of a shot. When you are trying to run that much bottle, and run high 8's. your cam kinda needs to be dedicated to either run all motor, or run all bottle, there isnt a good in between when you are talking about a setup like you have
Not optimal in the sense that I will loose power or not optimal in the sense that I will have nitrous backfires and blow stuff up. I know of a member on this board that sprays nitrous on a cam with much more overlap then that on a 408. Thanks.
03-10-2005, 12:12 PM
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Originally Posted by DAPSUPRSLO
Not optimal in the sense that I will loose power or not optimal in the sense that I will have nitrous backfires and blow stuff up. I know of a member on this board that sprays nitrous on a cam with much more overlap then that on a 408. Thanks.
03-10-2005, 01:38 PM
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Sounds like you have a very stout setup there.
I will be around 3000 raceweight. I will be running 4.56 gears and a six speed. I know this will not be an easy path but it will be a fun one. I'm going to do it in stages. I want to be around high 500s on the motor and then the nitrous will come into play. Should be fun.
I will be around 3000 raceweight. I will be running 4.56 gears and a six speed. I know this will not be an easy path but it will be a fun one. I'm going to do it in stages. I want to be around high 500s on the motor and then the nitrous will come into play. Should be fun.
03-10-2005, 11:32 PM
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Originally Posted by BTL FED
The big thing that causes head lifting is Cylinder Pressure, Which timing has a great deal to do with the pressures, also your cam design has a good bit to do with your cylinder pressures. The Afr heads would just allow you to get away with more timing.
For example A buddies engine I designed for him:
408 ci Ls1 Iron Block
Solid Roller
15 to 1 compression
241 heads
Arp L19 Head Studs
Cometic Gaskets
We started playing with it on the dyno last week with 300 worth of bottle, and no headgasket or headlifting problems. Tonight it goes back with 400 worth of bottle. These runs were made on C16 (118 octane) gas and 16 degrees of timing.
For example A buddies engine I designed for him:
408 ci Ls1 Iron Block
Solid Roller
15 to 1 compression
241 heads
Arp L19 Head Studs
Cometic Gaskets
We started playing with it on the dyno last week with 300 worth of bottle, and no headgasket or headlifting problems. Tonight it goes back with 400 worth of bottle. These runs were made on C16 (118 octane) gas and 16 degrees of timing.
