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Re: CNC'd ported vs hand ported heads: Discussion, long post
[Re: pittsburghracer]
#1876362
07/23/15 01:52 AM
07/23/15 01:52 AM
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Joined: Dec 2003
Posts: 22,696
Bitopia
jcc
If you can't dazzle em with diamonds..
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If you can't dazzle em with diamonds..
Joined: Dec 2003
Posts: 22,696
Bitopia
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Not sure what to make of this thread. Is the art of porting mainly based on some individual personal theories, with a prodigious amount of try and error on a flow bench? What happens when flow changes go down instead of up? If the art is slowly dying off, because of time and CNC, seems like the time for a well researched jointly written book, with chapters by each of the prominent willing head porters. Seems like the book would be able to be well priced if the secrets are shared by those in the twilight of their profession. The attraction to me would be reading all the different views, one, not so much. 
Reality check, that half the population is smarter then 50% of the people and it's a constantly contested fact.
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Re: CNC'd ported vs hand ported heads: Discussion, long post
[Re: jcc]
#1876375
07/23/15 02:05 AM
07/23/15 02:05 AM
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Joined: Feb 2005
Posts: 20,174
PA.
pittsburghracer
OP
"Little"John
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OP
"Little"John
Joined: Feb 2005
Posts: 20,174
PA.
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Head porting will never be a fits all for each build like a cnc head forces on you. When sitting down with a customer with hand porting you can shape the port to work for different builds. Play with a head on the flowbench that was prepped for a stock class car and you will be amazed.
1970 Duster
Edelbrock headed 408
5.984@112.52
422 Indy headed small block
5.982@112.56 mph
9.42@138.27
Livin and lovin life one day at a time
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Re: CNC'd ported vs hand ported heads: Discussion, long post
[Re: jcc]
#1876388
07/23/15 02:22 AM
07/23/15 02:22 AM
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Joined: Sep 2014
Posts: 4,457
Washington
madscientist
master
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master
Joined: Sep 2014
Posts: 4,457
Washington
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Not sure what to make of this thread. Is the art of porting mainly based on some individual personal theories, with a prodigious amount of try and error on a flow bench? What happens when flow changes go down instead of up? If the art is slowly dying off, because of time and CNC, seems like the time for a well researched jointly written book, with chapters by each of the prominent willing head porters. Seems like the book would be able to be well priced if the secrets are shared by those in the twilight of their profession. The attraction to me would be reading all the different views, one, not so much. I can tell you there is more to head work than flow numbers. The shape of the curve, how the head responds to pressure changes, how the port does in direction changes......just to name a few. I have done heads that flowed LESS when I was done that went faster. The port had issues. But because the original head guy was into big flow numbers he missed an important detail. I also love to kill "low" lift flow. If you think about it for a bit it will make sense. I'd write a book, but would you pay to read it??????????????
Just because you think it won't make it true. Horsepower is KING. To dispute this is stupid. C. Alston
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Re: CNC'd ported vs hand ported heads: Discussion, long post
[Re: pittsburghracer]
#1876389
07/23/15 02:23 AM
07/23/15 02:23 AM
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Joined: Sep 2014
Posts: 4,457
Washington
madscientist
master
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master
Joined: Sep 2014
Posts: 4,457
Washington
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[quote=pittsburghracer]Head porting will never be a fits all for each build like a cnc head forces on you. When sitting down with a customer with hand porting you can shape the port to work for different builds. Play with a head on the flowbench that was prepped for a stock class car and you will be amazed. [/quot
^^^^^^^^^^^^^^^^THIS^^^^^^^^^^^^^^^^^^^^^
Just because you think it won't make it true. Horsepower is KING. To dispute this is stupid. C. Alston
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Re: CNC'd ported vs hand ported heads: Discussion, long post
[Re: CDoering]
#1876421
07/23/15 04:58 AM
07/23/15 04:58 AM
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Joined: Jan 2003
Posts: 6,139
Melbourne , Australia
LA360
master
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master
Joined: Jan 2003
Posts: 6,139
Melbourne , Australia
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Good CNC shops can size the shape of the port based on engine design in the modeling software.
Check out Curtis Boggs Race Flow Developments web site or Facebook. I'm usually at his shop a few times a weeks and see this all the time. Curtis will usually CNC port one off heads as well
Alan Jones
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Re: CNC'd ported vs hand ported heads: Discussion, long post
[Re: LA360]
#1876423
07/23/15 06:25 AM
07/23/15 06:25 AM
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Joined: Jan 2003
Posts: 27,421
Balt. Md
383man
Too Many Posts
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Too Many Posts
Joined: Jan 2003
Posts: 27,421
Balt. Md
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I have always felt any CNC port job should always be finalized with hand porting as to me the CNC gets the basic job but will never be as good as when finished with a pro's final hand porting. Now I thought if a good head porter has a CNC machine and can put his good port prgram in it then it would save the porter alot of work by doing most of the work and then the porter can finish them up to be just right. It would save the porter alot of time and work so he only has to finish the job up and put the final touches on it.
I bought my heads from Dwayne Porter and he did some porting on them but not a ton of work and I was happy to have him port them as I feel he is one of if not the best out there. But if he had a CNC machine and had it do most of the work where he just did the final touches I would not blame a person who does porting for a living to use the CNC machine as it would save them alot of time and as long as its there program and they finish the job to there specs then I can see why they would use it. Ron
Last edited by 383man; 07/23/15 06:25 AM.
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Re: CNC'd ported vs hand ported heads: Discussion, long post
[Re: EchoSixMike]
#1876461
07/23/15 10:47 AM
07/23/15 10:47 AM
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Joined: Feb 2005
Posts: 20,174
PA.
pittsburghracer
OP
"Little"John
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OP
"Little"John
Joined: Feb 2005
Posts: 20,174
PA.
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CNC can do 95+% of the work in less than 5% of the time, allowing humans to do that last little bit(if it's worth it) and focus on important things like improving the entire system.
Do people actually enjoy the numb hands, sore backs, picking shards out of skin and hours and hours spent grinding out the bulk metal before you even get to the part that requires brainpower?
It's not one or the other; it's both focusing on what they're better suited to. S/F....Ken M
I just can't see paying twice to get it right. I could see if you got a GOOD cnc product but I've tested lots and they just aren't doing a very good job. They sure look pretty. A good Friend of mine challenged me to race my small tire car with his 20,000 dollar small block Ford with the pretty cnc heads and he can't even out-run my Edelbrock headed small block. LOL. He hasn't been quite so mouthy lately but I have a hard time keeping a straight face around him.
1970 Duster
Edelbrock headed 408
5.984@112.52
422 Indy headed small block
5.982@112.56 mph
9.42@138.27
Livin and lovin life one day at a time
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Re: CNC'd ported vs hand ported heads: Discussion, long post
[Re: pittsburghracer]
#1876495
07/23/15 11:56 AM
07/23/15 11:56 AM
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Joined: Feb 2005
Posts: 20,174
PA.
pittsburghracer
OP
"Little"John
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OP
"Little"John
Joined: Feb 2005
Posts: 20,174
PA.
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Thanks Jim. It gets kinda stale around here sometimes so I thought this would kinda be different. I was hoping Brett would stop in and give some input. He does some beautiful work and I would like to hear how his cnc program on W8, W9's stack up against ones he has hand ported. Track tested results are always my favorite.
1970 Duster
Edelbrock headed 408
5.984@112.52
422 Indy headed small block
5.982@112.56 mph
9.42@138.27
Livin and lovin life one day at a time
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Re: CNC'd ported vs hand ported heads: Discussion, long post
[Re: madscientist]
#1876516
07/23/15 12:28 PM
07/23/15 12:28 PM
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Joined: Dec 2003
Posts: 22,696
Bitopia
jcc
If you can't dazzle em with diamonds..
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If you can't dazzle em with diamonds..
Joined: Dec 2003
Posts: 22,696
Bitopia
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"I'd write a book, but would you pay to read it??????????????"
Absolutely, if there at least say 3? well known experienced proven porters contributing, anywhere from $100-250 a book. I also think different viewpoints are critical for the reader. Not sure if egos would allow a combined effort. That would be cheap info with the years of experience shared. Needs to be as textbook as possible, not a quick private library reading material read 3 pages at a time. However, I'm leery that the trial and error technique does not lend itself to printed page.
Reality check, that half the population is smarter then 50% of the people and it's a constantly contested fact.
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Re: CNC'd ported vs hand ported heads: Discussion, long post
[Re: EchoSixMike]
#1876522
07/23/15 12:32 PM
07/23/15 12:32 PM
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Joined: Sep 2014
Posts: 4,457
Washington
madscientist
master
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master
Joined: Sep 2014
Posts: 4,457
Washington
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CNC can do 95+% of the work in less than 5% of the time, allowing humans to do that last little bit(if it's worth it) and focus on important things like improving the entire system.
Do people actually enjoy the numb hands, sore backs, picking shards out of skin and hours and hours spent grinding out the bulk metal before you even get to the part that requires brainpower?
It's not one or the other; it's both focusing on what they're better suited to. S/F....Ken M
And here is the issue. You pay a 100% price for the CNC work and it's 95% (most time LESS than that). What Pittsburgh is seeing is exactly what I see. Hell yes, if I could afford a CNC I would use it in a nanosecond. But I would FINISH the heads BEFORE they left me and not lie to the customer and tell him not to touch the ports. I did read the interview with Larry Meaux (link is posted somewhere in the thread) and I have had 2 phone calls with him on surface finish. He said in the interview he has not done an A-B-A test on his finish. IIRC the interview is about 5 years old ands since then he has done SOME testing, but, IMHO, if he does not port at least 9 intakes to test, you really can't A-B-A them correctly. I have tried to simulate (as close as possible) his finish and don't get the results he is seeing. Probably 5-6 reasons for that. That's why you should find a head guy you can get along with, and do what he says. CNC machines are nothing but computerized RE-production machines. As long as you understand a CNC finished head is still not finished, you'll be ok. You have a set of heads that have not reached their potential, but, by gar, they are CNC'd.
Just because you think it won't make it true. Horsepower is KING. To dispute this is stupid. C. Alston
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Re: CNC'd ported vs hand ported heads: Discussion, long post
[Re: pittsburghracer]
#1876707
07/23/15 06:23 PM
07/23/15 06:23 PM
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Joined: Jun 2003
Posts: 52,972
Romeo MI
MR_P_BODY
Master
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Master
Joined: Jun 2003
Posts: 52,972
Romeo MI
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I'm no pro but I did learn from 2 of the best.. the first guy did all of the Mopar pro stock stuff back in the 70s.. he did all the heads for the Woodward garage guys which was the hot rod shop for Chrysler.. the other guy that I learned from... he taught.. this guy and me hired the same day at Chrysler and became good friends and I asked a ton of questions just to see if things had changed... he was the one who designed the swirl chamber.... I still like playing with it but I'll never do it for a living 
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Re: CNC'd ported vs hand ported heads: Discussion, long post
[Re: pittsburghracer]
#1876759
07/23/15 07:44 PM
07/23/15 07:44 PM
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Joined: Dec 2006
Posts: 3,395
Pa
Hot 340
master
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master
Joined: Dec 2006
Posts: 3,395
Pa
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Head porting will never be a fits all for each build like a cnc head forces on you. When sitting down with a customer with hand porting you can shape the port to work for different builds. Play with a head on the flowbench that was prepped for a stock class car and you will be amazed. Here's what im not understanding from this conversation... why does a cnc have to be one size fits all? Why are cnc porters only using one specific port program on one particular head? I wrote over a dozen cnc programs just today. Are these guys lazy? I would have a whole list of different programs for each application if that was my bread and butter.
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Re: CNC'd ported vs hand ported heads: Discussion, long post
[Re: madscientist]
#1876770
07/23/15 08:01 PM
07/23/15 08:01 PM
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Joined: Jan 2004
Posts: 8,257
fredericksburg,va
cudaman1969
master
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master
Joined: Jan 2004
Posts: 8,257
fredericksburg,va
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CNC can do 95+% of the work in less than 5% of the time, allowing humans to do that last little bit(if it's worth it) and focus on important things like improving the entire system.
Do people actually enjoy the numb hands, sore backs, picking shards out of skin and hours and hours spent grinding out the bulk metal before you even get to the part that requires brainpower?
It's not one or the other; it's both focusing on what they're better suited to. S/F....Ken M
And here is the issue. You pay a 100% price for the CNC work and it's 95% (most time LESS than that). What Pittsburgh is seeing is exactly what I see. Hell yes, if I could afford a CNC I would use it in a nanosecond. But I would FINISH the heads BEFORE they left me and not lie to the customer and tell him not to touch the ports. I did read the interview with Larry Meaux (link is posted somewhere in the thread) and I have had 2 phone calls with him on surface finish. He said in the interview he has not done an A-B-A test on his finish. IIRC the interview is about 5 years old ands since then he has done SOME testing, but, IMHO, if he does not port at least 9 intakes to test, you really can't A-B-A them correctly. I have tried to simulate (as close as possible) his finish and don't get the results he is seeing. Probably 5-6 reasons for that. That's why you should find a head guy you can get along with, and do what he says. CNC machines are nothing but computerized RE-production machines. As long as you understand a CNC finished head is still not finished, you'll be ok. You have a set of heads that have not reached their potential, but, by gar, they are CNC'd. What's is the price difference between CNC and hand porting same head? As long as someone understands the difference with the end result before buying i don't see an issue. Now if you're worried if someone has reinvented the wheel, that has been around since day one, like I said before we all have to educate our customers so they understand what we have to offer. The CNC machine is nothing but a better tool thats quicker and offers repeatability which means lees money, not more, to charge the customer. Honestly I can't see how all eight ports could be the same with hand porting verses CNC( think of the surface area of the complete port,20-40 sq in). Now the final blending by hand is a no brainier, has to be done. Can you imagine making an engine, by hand, without using all the machines it takes
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Re: CNC'd ported vs hand ported heads: Discussion, long post
[Re: Hot 340]
#1876790
07/23/15 08:36 PM
07/23/15 08:36 PM
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Joined: Jan 2003
Posts: 15,439
Val-haul-ass... eventually
BradH
Taking time off to work on my car
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Taking time off to work on my car
Joined: Jan 2003
Posts: 15,439
Val-haul-ass... eventually
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... why does a cnc have to be one size fits all? Why are cnc porters only using one specific port program on one particular head? It doesn't, and in some cases you'll find people who will offer different programs for the same casting, or different castings w/ application-specific programs to offer some options. But those guys are working w/ either highly specialized racing applications and raw castings intended for custom porting... or deal in a part of the performance industry where there are far more people to offer a variety of heads to (SBC & SBF).
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Re: CNC'd ported vs hand ported heads: Discussion, long post
[Re: cudaman1969]
#1876797
07/23/15 08:43 PM
07/23/15 08:43 PM
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Joined: Jan 2003
Posts: 15,439
Val-haul-ass... eventually
BradH
Taking time off to work on my car
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Taking time off to work on my car
Joined: Jan 2003
Posts: 15,439
Val-haul-ass... eventually
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... Honestly I can't see how all eight ports could be the same with hand porting verses CNC( think of the surface area of the complete port,20-40 sq in). Now the final blending by hand is a no brainier, has to be done... Even my CNC'd Victors don't all flow the same (I've tested every intake port), simply because they're production castings w/ a certain level of core shift and have places where the CNC program doesn't touch each head exactly the same way. The only way I'd expect a CNC'd head to flow exactly the same (give or take some small %) is if it starts w/ a raw undersized casting where the tooling touches basically every port & chamber identically. Any dropout means inconsistency, and applying a CNC program to any head already cast intended for use "as is" means that's a likely result. Even then, I recall a porter who was doing a lot of CNC stuff w/ production based heads saying the final CNC'd version was a success if it flowed w/in some particular # of CFM of the hand-ported prototype which was digitized for the program. He didn't expect his own CNC'd heads to equal his hand-ported results, but it was a helluva lot faster to reproduce the basic port for mass consumption.
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