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Re: Improving cnc ported heads
[Re: B3422W5]
#2421085
12/19/17 07:50 PM
12/19/17 07:50 PM
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Joined: Oct 2011
Posts: 3,036
bean town ....Ca
WHITEDART
master
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master
Joined: Oct 2011
Posts: 3,036
bean town ....Ca
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if it makes you feel any better.. I am yet to see a c&c head flow as good as they're advertised.. most head companies these days r more into selling a flow number...
Last edited by WHITEDART; 12/19/17 09:46 PM.
In the 8s N/A.with Brett miller W8's
5.07 at 133 at 2700lb
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Re: Improving cnc ported heads
[Re: B3422W5]
#2421211
12/19/17 11:34 PM
12/19/17 11:34 PM
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Joined: Oct 2007
Posts: 4,206
New York
polyspheric
master
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master
Joined: Oct 2007
Posts: 4,206
New York
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Larry Widmer very strong on CFM numbers are less important than velocity at the right lift, producing best transitional horsepower (only shows up on an RPM per second dyno).
Boffin Emeritus
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Re: Improving cnc ported heads
[Re: polyspheric]
#2421400
12/20/17 12:43 PM
12/20/17 12:43 PM
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Joined: Sep 2003
Posts: 19,396
north of coder
moparx
"Butt Crack Bob"
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"Butt Crack Bob"
Joined: Sep 2003
Posts: 19,396
north of coder
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There may be differences in result quality between 2 different programs and 2 different CNC fixtures from the same (already ported) head.
How is that possible?
One takes smaller readings with the probe, at more angles, then uses more passes and smaller cutters at more axes (hours longer to complete).
In some castings (not all) the difference may be significant, especially with small ports and 3 dimensional curves. this  something i learned over my 42+ year machining career dealing with castings, both virgin and finished/repaired, although dealing with natural gas transmission meters instead of cylinder heads. also, different cutters most definitely affect flow, sometimes in mysterious ways, such as the helix difference in same sized end mills used in contour cutting. 
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Re: Improving cnc ported heads
[Re: Ian]
#2422496
12/22/17 11:27 PM
12/22/17 11:27 PM
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Joined: Aug 2003
Posts: 43,161
Bend,OR USA
Cab_Burge
I Win
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I Win
Joined: Aug 2003
Posts: 43,161
Bend,OR USA
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Where both test done on the same machine and in similar weather conditions?
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
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Re: Improving cnc ported heads
[Re: Cab_Burge]
#2422507
12/22/17 11:42 PM
12/22/17 11:42 PM
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Joined: Jan 2009
Posts: 1,044
Victoria, Australia
Ian
super stock
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super stock
Joined: Jan 2009
Posts: 1,044
Victoria, Australia
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Where both test done on the same machine and in similar weather conditions? same day 2 hrs apart same port same bench mate
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Re: Improving cnc ported heads
[Re: Ian]
#2422578
12/23/17 03:53 AM
12/23/17 03:53 AM
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Joined: Aug 2003
Posts: 43,161
Bend,OR USA
Cab_Burge
I Win
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I Win
Joined: Aug 2003
Posts: 43,161
Bend,OR USA
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Where both test done on the same machine and in similar weather conditions? same day 2 hrs apart same port same bench mate 
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
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Re: Improving cnc ported heads
[Re: polyspheric]
#2422942
12/24/17 01:12 AM
12/24/17 01:12 AM
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Joined: Oct 2003
Posts: 7,506
Az
Crizila
master
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master
Joined: Oct 2003
Posts: 7,506
Az
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heads are only so thick, once you get them thin, seats start to move around
This^^^
Vizard reported on intake valves that didn't seat properly because the seat itself moved laterally when hot. The cure: weaken the valve head so it bends to conform. !!!
Vizard reading his weegie board again. Anyone who does this needs a frontal lobotomy.
Fastest 300
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