Gen IV smallblock......
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Joined: Jul 2002
Posts: 816
From: San Diego PB
Re: What is the benefit?
Originally posted by cjwilson99
What is the benefit of having an extra Intake valve if they open at the same time? Why not make the one intake valve bigger?
Disclaimer: The below info is provided from my mind as I remember. If somebody knows different please correct me.
I mean in the days of the 305/350, the drawback of the 305 was the limit in intake valve size (besides the lack of cubes). I believe the max intake valve size was 1.94 inches. So people preferred the 350 because putting a head with 2.02-inch intake valves really woke that puppy up if you had a cam that would take advantage of it. If I am not mistaken the LS1 has an intake valve size of 2.00. Can it not be made bigger because the valve shrouding of the cylinder bore? According to Mortec.com the old 305 and the newer 4.8\5.3 have almost the same cylinder bore so just making the intake valve bigger may not be an option for those engines but the ls1\6 5.7 liter and bigger performance engines would benefit from just using a bigger valve.
Bore:
305 = 3.740"
5.3\4.8 = 3.780'
I guess my question in short would be " What is the benefit of a 2nd intake valve other than more flow?" And "If flow is the only benefit then why not just use a bigger intake valve on performance engines?" Is there an engineer or somebody in the know that can answers these questions?
What is the benefit of having an extra Intake valve if they open at the same time? Why not make the one intake valve bigger?
Disclaimer: The below info is provided from my mind as I remember. If somebody knows different please correct me.
I mean in the days of the 305/350, the drawback of the 305 was the limit in intake valve size (besides the lack of cubes). I believe the max intake valve size was 1.94 inches. So people preferred the 350 because putting a head with 2.02-inch intake valves really woke that puppy up if you had a cam that would take advantage of it. If I am not mistaken the LS1 has an intake valve size of 2.00. Can it not be made bigger because the valve shrouding of the cylinder bore? According to Mortec.com the old 305 and the newer 4.8\5.3 have almost the same cylinder bore so just making the intake valve bigger may not be an option for those engines but the ls1\6 5.7 liter and bigger performance engines would benefit from just using a bigger valve.
Bore:
305 = 3.740"
5.3\4.8 = 3.780'
I guess my question in short would be " What is the benefit of a 2nd intake valve other than more flow?" And "If flow is the only benefit then why not just use a bigger intake valve on performance engines?" Is there an engineer or somebody in the know that can answers these questions?
As far as the camless engines go, Coate's Spherical Rotary Valves are vaporware, they don't exist, and they don't sell them to anybody and they sure as hell don't have any plans to, vaporware, crap, blah.
Now for solenoid operated valves, that is another matter and is in actual use today.
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Joined: Nov 2000
Posts: 1,440
From: five-one-oh/nine-oh-nine
i think all the electronic/electric camless ideas are crap. solenoids are just wire wrapped over an insulating pipe. they're just coils. coils aren't exactly everlasting, they burn out no matter how good they are. especially when they are constantly used as they would be actuating the valves, going on/off all the time in high surrounding heat. and they would likely burn out much, much sooner than any cam would ever wear out and stop pushing on the valves. then there would be problems with partial operation and shorting, not to mention that it would first mean going to a higher volt electric system because of the EMF required to operate all of those solenoids. the current 12v systems are already near to being maxed out on the amount of usable current they can produce. unless the whole engine is turned into a giant generator. on top of that it almost means towing a computer with the power of a PC with redundency systems just to properly controll all those solenoids.
this is all just needless complication without much real benifit. systems are supposed to evolve and become more effecient.
this is all just needless complication without much real benifit. systems are supposed to evolve and become more effecient.
Thread Starter
Registered User
Joined: Nov 2000
Posts: 16,176
From: Chicagoland IL
Just getting back to a good looking engine...
Katech knows how to tidy up a Gen III smallblock.
http://www.katechengines.com/
http://www.z06vette.com/pitroad3.php
Katech knows how to tidy up a Gen III smallblock.
http://www.katechengines.com/
http://www.z06vette.com/pitroad3.php
Registered User
Joined: Jul 2002
Posts: 816
From: San Diego PB
Originally posted by morb|d
i think all the electronic/electric camless ideas are crap. solenoids are just wire wrapped over an insulating pipe. they're just coils. coils aren't exactly everlasting, they burn out no matter how good they are. especially when they are constantly used as they would be actuating the valves, going on/off all the time in high surrounding heat. and they would likely burn out much, much sooner than any cam would ever wear out and stop pushing on the valves. then there would be problems with partial operation and shorting, not to mention that it would first mean going to a higher volt electric system because of the EMF required to operate all of those solenoids. the current 12v systems are already near to being maxed out on the amount of usable current they can produce. unless the whole engine is turned into a giant generator. on top of that it almost means towing a computer with the power of a PC with redundency systems just to properly controll all those solenoids.
this is all just needless complication without much real benifit. systems are supposed to evolve and become more effecient.
i think all the electronic/electric camless ideas are crap. solenoids are just wire wrapped over an insulating pipe. they're just coils. coils aren't exactly everlasting, they burn out no matter how good they are. especially when they are constantly used as they would be actuating the valves, going on/off all the time in high surrounding heat. and they would likely burn out much, much sooner than any cam would ever wear out and stop pushing on the valves. then there would be problems with partial operation and shorting, not to mention that it would first mean going to a higher volt electric system because of the EMF required to operate all of those solenoids. the current 12v systems are already near to being maxed out on the amount of usable current they can produce. unless the whole engine is turned into a giant generator. on top of that it almost means towing a computer with the power of a PC with redundency systems just to properly controll all those solenoids.
this is all just needless complication without much real benifit. systems are supposed to evolve and become more effecient.
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