Determining the correct valve opening and closing points

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In-Tech
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Re: Determining the correct valve opening and closing points

Post by In-Tech » Thu Apr 11, 2019 1:42 pm

Hello f'bird,
The "idea" of what David does is, it will put you in a ballpark. This can not be compared to 1d which can easily be made futile. I posted one exact engine with different timing events and produced EXACTLY what I wanted, same chassis dyno, same conditions. All I got in response was 128 wasn't for circle track.

I am not for, nor against, any software. They are tools just like the dyno. You can learn from both. One doesn't lie when you are changing parts.
Heat is energy, energy is horsepower...but you gotta control the heat.
-Carl

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Re: Determining the correct valve opening and closing points

Post by Krooser » Thu Apr 11, 2019 1:46 pm

Selecting the correct timing events and that determines your lsa...
Last place in the B-main is better than anyplace in the grandstands...

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Re: Determining the correct valve opening and closing points

Post by Sumtingwong » Thu Apr 11, 2019 2:16 pm

F-BIRD'88 wrote:
Thu Apr 11, 2019 1:25 pm
The problem with the Vizard 128 method is that NOBODY HAS PRODUCED ANY DYNO TEST DATA TO PROVE IT OR DIS PROVE IT... Lots of dynos. Lots of talk... No Testing. Anywhere to debunk it or validate it..
DV Doesn't have opinions he has a dyno//i'm sure he would display the dyno data to prove his principle if asked but may be busy building his winning engine for the dyno race contest he works very long days and is probably on his dyno as we are talking

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Re: Determining the correct valve opening and closing points

Post by SchmidtMotorWorks » Thu Apr 11, 2019 2:43 pm

Rules of thumb, simple formula and dyno testing don't provide any insight as to what is happening in your engine.
The companies with the best dyno facilities in the world use simulation to guide their dyno testing.
Throwing parts at an engine to see what it does to the power curve is as out of date as typewriters.

In fact AVL makes both high-end dynos and simulation systems.
http://www.schmidtmotorworks.com Aerospace Machine Work: Prototypes, Tooling, Molds.

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Re: Determining the correct valve opening and closing points

Post by F-BIRD'88 » Thu Apr 11, 2019 2:56 pm

No, David Vizard said he does have data but cannot present it easily because A. Its sitting in California and
B. It is propriatory and does not all belong to him, to publish in whole form.
But that was then, this is now.
I'd like to see this proven or debunked by other independant dyno test data.

New or archived dyno tests. Valid data is valid data, one way or the other.
It need not be 1000's of dyno pulls to see a trend for or against.
After all the whole purpose of his 128 method is for OTHER PEOPLE to gain from employing his method. I think it has merrit.
Yes, to get you in the ballpark.

My opinion is that it has some merrit.. Maybe a Lot of merrit.

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Re: Determining the correct valve opening and closing points

Post by In-Tech » Thu Apr 11, 2019 3:02 pm

SchmidtMotorWorks wrote:
Thu Apr 11, 2019 2:43 pm
Rules of thumb, simple formula and dyno testing don't provide any insight as to what is happening in your engine.
The companies with the best dyno facilities in the world use simulation to guide their dyno testing.
Throwing parts at an engine to see what it does to the power curve is as out of date as typewriters.

In fact AVL makes both high-end dynos and simulation systems.
Ed Zachery what I was saying. To guide.
Heat is energy, energy is horsepower...but you gotta control the heat.
-Carl

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Re: Determining the correct valve opening and closing points

Post by GARY C » Thu Apr 11, 2019 11:52 pm

Sumtingwong wrote:
Thu Apr 11, 2019 2:16 pm
F-BIRD'88 wrote:
Thu Apr 11, 2019 1:25 pm
The problem with the Vizard 128 method is that NOBODY HAS PRODUCED ANY DYNO TEST DATA TO PROVE IT OR DIS PROVE IT... Lots of dynos. Lots of talk... No Testing. Anywhere to debunk it or validate it..
DV Doesn't have opinions he has a dyno//i'm sure he would display the dyno data to prove his principle if asked but may be busy building his winning engine for the dyno race contest he works very long days and is probably on his dyno as we are talking
He has actually done it in reverse, he has been publishing his dyno test results for decades that lead him to come up with 128 so the average guy would not be at the mercy of the cam counter salesman.

He has posted a cpl of builds here with cams that could have been selected using it, if you reduce valve diameter accordingly it seems to put you in the same range as some steep seat builds I have seen. :)
Please Note!
THE ABOVE POST IN NO WAY REFLECTS THE VIEWS OF SPEED TALK OR IT'S MEMBER AND SHOULD BE VIEWED AS ENTERTAINMENT ONLY...Thanks, The Management!

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Re: Determining the correct valve opening and closing points

Post by Orr89rocz » Fri Apr 12, 2019 7:09 am

F-BIRD'88 wrote:
Thu Apr 11, 2019 2:56 pm
No, David Vizard said he does have data but cannot present it easily because A. Its sitting in California and
B. It is propriatory and does not all belong to him, to publish in whole form.
But that was then, this is now.
I'd like to see this proven or debunked by other independant dyno test data.

New or archived dyno tests. Valid data is valid data, one way or the other.
It need not be 1000's of dyno pulls to see a trend for or against.
After all the whole purpose of his 128 method is for OTHER PEOPLE to gain from employing his method. I think it has merrit.
Yes, to get you in the ballpark.

My opinion is that it has some merrit.. Maybe a Lot of merrit.
Did the book have data?

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Re: Determining the correct valve opening and closing points

Post by EDC » Fri Apr 12, 2019 7:46 am

After reading all this drivel, an old proverb told to me nearly five decades ago still applies...

"There are absolutely no absolutes."

Carry on... :mrgreen:
"Quality" is like buying oats. You can pay a fair price for it and get some good quality oats,
or you can get it a hell of a lot cheaper, when it's already been through the horse.

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Re: Determining the correct valve opening and closing points

Post by GARY C » Fri Apr 12, 2019 3:13 pm

EDC wrote:
Fri Apr 12, 2019 7:46 am
After reading all this drivel, an old proverb told to me nearly five decades ago still applies...

"There are absolutely no absolutes."

Carry on... :mrgreen:
Isn't that whats known as a self defeating statement?

When I here that I think of the laws that govern the universe, how to handle money and death. :)
Please Note!
THE ABOVE POST IN NO WAY REFLECTS THE VIEWS OF SPEED TALK OR IT'S MEMBER AND SHOULD BE VIEWED AS ENTERTAINMENT ONLY...Thanks, The Management!

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Re: Determining the correct valve opening and closing points

Post by BigBro74 » Fri Apr 12, 2019 8:55 pm

Orr89rocz wrote:
Fri Apr 12, 2019 7:09 am
F-BIRD'88 wrote:
Thu Apr 11, 2019 2:56 pm
No, David Vizard said he does have data but cannot present it easily because A. Its sitting in California and
B. It is propriatory and does not all belong to him, to publish in whole form.
But that was then, this is now.
I'd like to see this proven or debunked by other independant dyno test data.

New or archived dyno tests. Valid data is valid data, one way or the other.
It need not be 1000's of dyno pulls to see a trend for or against.
After all the whole purpose of his 128 method is for OTHER PEOPLE to gain from employing his method. I think it has merrit.
Yes, to get you in the ballpark.

My opinion is that it has some merrit.. Maybe a Lot of merrit.
Did the book have data?
I have to say-- if you had read the book, you would know ir the book had data :)
The problem is, most people that comment didn't ever read any of the books ..............

I like to read books several times-----slowly.
There are a lot of little important details in books, and they show up when you do that.

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Re: Determining the correct valve opening and closing points

Post by GARY C » Fri Apr 12, 2019 10:05 pm

BigBro74 wrote:
Fri Apr 12, 2019 8:55 pm
Orr89rocz wrote:
Fri Apr 12, 2019 7:09 am
F-BIRD'88 wrote:
Thu Apr 11, 2019 2:56 pm
No, David Vizard said he does have data but cannot present it easily because A. Its sitting in California and
B. It is propriatory and does not all belong to him, to publish in whole form.
But that was then, this is now.
I'd like to see this proven or debunked by other independant dyno test data.

New or archived dyno tests. Valid data is valid data, one way or the other.
It need not be 1000's of dyno pulls to see a trend for or against.
After all the whole purpose of his 128 method is for OTHER PEOPLE to gain from employing his method. I think it has merrit.
Yes, to get you in the ballpark.

My opinion is that it has some merrit.. Maybe a Lot of merrit.
Did the book have data?
I have to say-- if you had read the book, you would know ir the book had data :)
The problem is, most people that comment didn't ever read any of the books ..............

I like to read books several times-----slowly.
There are a lot of little important details in books, and they show up when you do that.
This is something our fast food world has forgotten, new technology comes from old data, I think you stand to learn and progress more by going back to the basics from time to time.

Keeping track of how we got to where we are also helps to understand where we are going and keeps you from getting stuck on where we are at.
Please Note!
THE ABOVE POST IN NO WAY REFLECTS THE VIEWS OF SPEED TALK OR IT'S MEMBER AND SHOULD BE VIEWED AS ENTERTAINMENT ONLY...Thanks, The Management!

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Re: Determining the correct valve opening and closing points

Post by Olds455 » Sat Apr 13, 2019 9:01 am

F-BIRD'88 wrote:
Thu Apr 11, 2019 1:25 pm
The problem with the Vizard 128 method is that NOBODY HAS PRODUCED ANY DYNO TEST DATA TO PROVE IT OR DIS PROVE IT... Lots of dynos. Lots of talk... No Testing. Anywhere to debunk it or validate it..
I have 2 very different CID sbc motors (a 305 and a 406 cid sbc) and 3 pairs of cylinder heads with different valves, chambers and airflow and compression ratio
Results by swaping them around. Have a independent dyno facility available (no skin in this game) but its not free. Lack time and money
My testing would be relative simple on these 2 simple but relavent engines.
I include David Vizard himself as well as all you big shot race shop owners w engine dynos, in this critiism.
No Data...

I did find a dyno data set comparo of thumpr hed cams vs Extreme hyd cams (107- vs 110 lsa) on a 350 sbc that DOES SUPPORT THE CLAIMS OF THE DV 128 method,.

One note on this cam lsa test set is that the 110 lsa cam was never retested on any other installed intake c/l besides default to see if and how much more that simple tuning change could have improved the overall tirque curve...

I ALLWAYS tell people with these off the shelf catalog 110 lsa cams to play with the installed Intake Centerline
To find the best spot for YOUR car. Move that cam around a bit to find the sweet spot even if it is not the perfect cam. The default 106/114 phasing is not always optimum at all, on these popular cams.

You can use some of the 128 method and a bit of the intake valve lift at TDC method math combined and a bit of horse sense to guide you . testing will verify.

On a sbc, if you've got some different ratio rockers on hand you can fine tune the intake side overlap -lift at tdc a bit
To help make your cam act as a better match the called for 128 cam.

You say this but you're not taking everything into consideration, it seems. First, is your data skewed? Remember that David didn't initially collect the data looking for changes between cams that didn't match a pattern. He took thousands of dyno runs, compiled the data with no determined point that he was trying to prove nor disprove, observed patterns, and came up with his 128 deal as far as I know. And I don't claim to know much of anything about him.

That's a lot different that doing each and every dyno run with the intent of trying to prove or disprove that the results from 1, 2,.or even 10 tests match the patten he determined from thousands of dyno runs. There's no comparison, imo. And any attempt without years of testing and data compilation is in vain.

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Re: Determining the correct valve opening and closing points

Post by RevTheory » Sat Apr 13, 2019 9:59 am

Olds455 wrote:
Sat Apr 13, 2019 9:01 am

You say this but you're not taking everything into consideration, it seems. First, is your data skewed? Remember that David didn't initially collect the data looking for changes between cams that didn't match a pattern. He took thousands of dyno runs, compiled the data with no determined point that he was trying to prove nor disprove, observed patterns, and came up with his 128 deal as far as I know. And I don't claim to know much of anything about him.

That's a lot different that doing each and every dyno run with the intent of trying to prove or disprove that the results from 1, 2,.or even 10 tests match the patten he determined from thousands of dyno runs. There's no comparison, imo. And any attempt without years of testing and data compilation is in vain.
People should actually be commended for simply following the data. How many of the guys who constantly bash DV secretly wish that a major cam company had contacted them for a 4-year, fully-funded R&D project?

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Re: Determining the correct valve opening and closing points

Post by Stan Weiss » Sat Apr 13, 2019 10:04 am

Olds455 wrote:
Sat Apr 13, 2019 9:01 am
F-BIRD'88 wrote:
Thu Apr 11, 2019 1:25 pm
The problem with the Vizard 128 method is that NOBODY HAS PRODUCED ANY DYNO TEST DATA TO PROVE IT OR DIS PROVE IT... Lots of dynos. Lots of talk... No Testing. Anywhere to debunk it or validate it..
I have 2 very different CID sbc motors (a 305 and a 406 cid sbc) and 3 pairs of cylinder heads with different valves, chambers and airflow and compression ratio
Results by swaping them around. Have a independent dyno facility available (no skin in this game) but its not free. Lack time and money
My testing would be relative simple on these 2 simple but relavent engines.
I include David Vizard himself as well as all you big shot race shop owners w engine dynos, in this critiism.
No Data...

I did find a dyno data set comparo of thumpr hed cams vs Extreme hyd cams (107- vs 110 lsa) on a 350 sbc that DOES SUPPORT THE CLAIMS OF THE DV 128 method,.

One note on this cam lsa test set is that the 110 lsa cam was never retested on any other installed intake c/l besides default to see if and how much more that simple tuning change could have improved the overall tirque curve...

I ALLWAYS tell people with these off the shelf catalog 110 lsa cams to play with the installed Intake Centerline
To find the best spot for YOUR car. Move that cam around a bit to find the sweet spot even if it is not the perfect cam. The default 106/114 phasing is not always optimum at all, on these popular cams.

You can use some of the 128 method and a bit of the intake valve lift at TDC method math combined and a bit of horse sense to guide you . testing will verify.

On a sbc, if you've got some different ratio rockers on hand you can fine tune the intake side overlap -lift at tdc a bit
To help make your cam act as a better match the called for 128 cam.

You say this but you're not taking everything into consideration, it seems. First, is your data skewed? Remember that David didn't initially collect the data looking for changes between cams that didn't match a pattern. He took thousands of dyno runs, compiled the data with no determined point that he was trying to prove nor disprove, observed patterns, and came up with his 128 deal as far as I know. And I don't claim to know much of anything about him.

That's a lot different that doing each and every dyno run with the intent of trying to prove or disprove that the results from 1, 2,.or even 10 tests match the patten he determined from thousands of dyno runs. There's no comparison, imo. And any attempt without years of testing and data compilation is in vain.
I believe the bases for David's COS CAM program which he boiled down to the 128 one liner, was 1000's of dyno tests he did with / for Harvey Crane.

Stan
Stan Weiss / World Wide Enterprises
Offering Performance Software Since 1987
Do you use engine simulation software that uses cylinder head flow files?
We have a package of more than 3000 DFW or FLW Files

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