Determining the correct valve opening and closing points

General engine tech -- Drag Racing to Circle Track

Moderator: Team

Post Reply
Boz-Race Engines
Pro
Pro
Posts: 326
Joined: Tue Feb 09, 2010 9:56 am
Location: PERTH AUSTRALIA

Re: Determining the correct valve opening and closing points

Post by Boz-Race Engines » Mon Apr 15, 2019 10:42 am

I agree with cjperformance it would be a great idea for every member to have proper contact details and identities on here, so many hide behind fake identities and made up names, just imagine all the fake builds and tests and other bull crap stories that are on here? lol, at least DV runs under his own name and actually puts some data up, and at least we all know who he is, which is more than I can say for a lot of members on here! its a great forum most days but some people just sh#t me to no end with their crap on here some days. always someone ready to shoot someone down, its very tiring sometimes. hence why I don't get on here a lot plus the fact im always quite busy doing what I do for a living.
Its hard to move forward if you have a closed mind,
http://www.davidvizardperformanceseminars.com/

paulzig
Pro
Pro
Posts: 477
Joined: Sun Aug 03, 2008 6:29 am
Location: Australia

Re: Determining the correct valve opening and closing points

Post by paulzig » Mon Apr 15, 2019 4:32 pm

The exclamation point in someones post is the report feature, you click on that and it will send a report to the admin team. If there still is an admin team maybe they should hand out bans?

User avatar
MadBill
Guru
Guru
Posts: 13882
Joined: Tue Nov 15, 2005 10:41 am
Location: The Great White North

Re: Determining the correct valve opening and closing points

Post by MadBill » Mon Apr 15, 2019 5:08 pm

paulzig wrote:
Mon Apr 15, 2019 4:32 pm
The exclamation point in someones post is the report feature, you click on that and it will send a report to the admin team. If there still is an admin team maybe they should hand out bans?
They did for sure on Don's watch, hopefully still will if necessary. Quite a number of contentious posters are no longer with us. (or perhaps have re-upped with better attitudes...)
Felix, qui potuit rerum cognscere causas.

Happy is he who can discover the cause of things.

GARY C
Guru
Guru
Posts: 5040
Joined: Tue May 14, 2013 10:58 pm

Re: Determining the correct valve opening and closing points

Post by GARY C » Mon Apr 15, 2019 6:31 pm

I find it interesting that you can't discuss a simple way to baseline valve events in a thread about valve events without some loosing their mind... It's like 128 is the MAGA Hat of engine building.

MEBSA... Make Engine Building Simple Again! :lol:
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!

digger
Guru
Guru
Posts: 1459
Joined: Sun Jan 27, 2008 6:39 am

Re: Determining the correct valve opening and closing points

Post by digger » Mon Apr 15, 2019 7:09 pm

GARY C wrote:
Mon Apr 15, 2019 6:31 pm
I find it interesting that you can't discuss a simple way to baseline valve events in a thread about valve events without some loosing their mind... It's like 128 is the MAGA Hat of engine building.

MEBSA... Make Engine Building Simple Again! :lol:
Gary the 128 method does not definitively allow determination of the 4 valve events. The overlap you choose to is very subjective.

GARY C
Guru
Guru
Posts: 5040
Joined: Tue May 14, 2013 10:58 pm

Re: Determining the correct valve opening and closing points

Post by GARY C » Mon Apr 15, 2019 7:57 pm

digger wrote:
Mon Apr 15, 2019 7:09 pm
GARY C wrote:
Mon Apr 15, 2019 6:31 pm
I find it interesting that you can't discuss a simple way to baseline valve events in a thread about valve events without some loosing their mind... It's like 128 is the MAGA Hat of engine building.

MEBSA... Make Engine Building Simple Again! :lol:
Gary the 128 method does not definitively allow determination of the 4 valve events. The overlap you choose to is very subjective.
True, The overlap part does take some searching on engines your not familiar with and would be my biggest complaint about it but i have found if you do a little searching it is not hard to find some corresponding builds to see whats needed for a given rpm.

Even just playing with a simple free program like the one here can help you dial in what you are trying to get to.
http://cochise.uia.net/pkelley2/DynamicCR.html
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!

novadude
Guru
Guru
Posts: 1340
Joined: Thu Oct 11, 2007 3:24 pm
Location: Shippensburg, PA

Re: Determining the correct valve opening and closing points

Post by novadude » Mon Apr 15, 2019 8:18 pm

digger wrote:
Mon Apr 15, 2019 7:09 pm
GARY C wrote:
Mon Apr 15, 2019 6:31 pm
I find it interesting that you can't discuss a simple way to baseline valve events in a thread about valve events without some loosing their mind... It's like 128 is the MAGA Hat of engine building.

MEBSA... Make Engine Building Simple Again! :lol:
Gary the 128 method does not definitively allow determination of the 4 valve events. The overlap you choose to is very subjective.
Selecting the right overlap is one area where I would like to see DV give some more specific advice / guidance. What is written in his books is a little vague. I'm thinking the same 50 deg of overlap (for example) might perform different in a 400 SBC with 2.02/1.60 valves vs a 402 ci BBC with 2.19/1.88 valves.

I know '128' is not well accepted here, but I believe it is a really good attempt at guiding home amateur schmucks like me in the right direction. I believe it can get the home builder a lot closer to the "right" cam than a call to the comp tech line.

novadude
Guru
Guru
Posts: 1340
Joined: Thu Oct 11, 2007 3:24 pm
Location: Shippensburg, PA

Re: Determining the correct valve opening and closing points

Post by novadude » Mon Apr 15, 2019 8:24 pm

CamKing wrote:
Sat Apr 13, 2019 2:16 pm
Many "Performance" companies spend all their money making their product look good, instead of making it good.
My personal opinion is that Comp has perfected this art.
David is good at what he does, but what he does, is not what I do. He gets paid to help the below average engine builder become an above average engine builder. That's great, and very helpful to the industry, by education more people, to understand how an engine works, and how it's not "Black Magic.
Very well said. DV has helped guys like me that don't do this stuff for a living. I cannot think of any other publications released in the last 30 years for the home builder that have provided the depth of knowledge that is in some of DV's many books. Some good stuff in the old Grumpy books, Smokey books, etc, but most of everything else being published today is just fluff.

RevTheory
Guru
Guru
Posts: 5105
Joined: Thu Sep 04, 2014 6:45 am

Re: Determining the correct valve opening and closing points

Post by RevTheory » Mon Apr 15, 2019 9:02 pm

Even DV's overlap charts, that I agree could probably use some better clarification, will get you well within the "squabbling over a couple of degrees" range of person opinion.

At least 128 gets you an LSA that would take dyno testing to improve upon, assuming it's used where it's supposed to be used. In a normal world, something like that would be welcomed.

digger
Guru
Guru
Posts: 1459
Joined: Sun Jan 27, 2008 6:39 am

Re: Determining the correct valve opening and closing points

Post by digger » Mon Apr 15, 2019 9:20 pm

RevTheory wrote:
Mon Apr 15, 2019 9:02 pm
Even DV's overlap charts, that I agree could probably use some better clarification, will get you well within the "squabbling over a couple of degrees" range of person opinion.

At least 128 gets you an LSA that would take dyno testing to improve upon, assuming it's used where it's supposed to be used. In a normal world, something like that would be welcomed.
Drip feeding info does not help.
Normally one post everything in the one spot so the equation and the assumptions or limitations with its use are known. Some of the early stuff presented made it sound like it could be used for anything and everything but now the horse has bolted.....

GARY C
Guru
Guru
Posts: 5040
Joined: Tue May 14, 2013 10:58 pm

Re: Determining the correct valve opening and closing points

Post by GARY C » Mon Apr 15, 2019 9:20 pm

novadude wrote:
Mon Apr 15, 2019 8:18 pm
digger wrote:
Mon Apr 15, 2019 7:09 pm
GARY C wrote:
Mon Apr 15, 2019 6:31 pm
I find it interesting that you can't discuss a simple way to baseline valve events in a thread about valve events without some loosing their mind... It's like 128 is the MAGA Hat of engine building.

MEBSA... Make Engine Building Simple Again! :lol:
Gary the 128 method does not definitively allow determination of the 4 valve events. The overlap you choose to is very subjective.
Selecting the right overlap is one area where I would like to see DV give some more specific advice / guidance. What is written in his books is a little vague. I'm thinking the same 50 deg of overlap (for example) might perform different in a 400 SBC with 2.02/1.60 valves vs a 402 ci BBC with 2.19/1.88 valves.

I know '128' is not well accepted here, but I believe it is a really good attempt at guiding home amateur schmucks like me in the right direction. I believe it can get the home builder a lot closer to the "right" cam than a call to the comp tech line.
Yes the overlap is dependent on engine and size to some extent as is 128, the overlap chart in his BBC book would be different than that in the SBC book as well as a BBC would use 132 not 128.

Just looking at a few different engines I have cam master sheets on that I have built over the last several years a 9.5 331 with a 276 on a 110, a 10.1 357 with a 274 on a 109, a 9.5 412 with 268 on a 106 all at 54 to 55 overlap and a 10.1 355 with a 262 on a 109 with 43 overlap.

Just a rough idea of a few I have done along those lines because I do not like more than 55 OL for a street cam, these had right around 195 to a little over 200 (43 overlap cam) cranking psi.

In comparison for a 496 with an oval port AFR head and a 2.300 valve for a street engine 10.1 and around 6300/6500 range you would have something in the 290 on a 107 with a 76 overlap.
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!

GARY C
Guru
Guru
Posts: 5040
Joined: Tue May 14, 2013 10:58 pm

Re: Determining the correct valve opening and closing points

Post by GARY C » Mon Apr 15, 2019 9:37 pm

digger wrote:
Mon Apr 15, 2019 9:20 pm
RevTheory wrote:
Mon Apr 15, 2019 9:02 pm
Even DV's overlap charts, that I agree could probably use some better clarification, will get you well within the "squabbling over a couple of degrees" range of person opinion.

At least 128 gets you an LSA that would take dyno testing to improve upon, assuming it's used where it's supposed to be used. In a normal world, something like that would be welcomed.
Drip feeding info does not help.
Normally one post everything in the one spot so the equation and the assumptions or limitations with its use are known. Some of the early stuff presented made it sound like it could be used for anything and everything but now the horse has bolted.....
I will take you serious on that when you say the same to Jon and others that post little to nothing in this context.
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!

digger
Guru
Guru
Posts: 1459
Joined: Sun Jan 27, 2008 6:39 am

Re: Determining the correct valve opening and closing points

Post by digger » Mon Apr 15, 2019 9:47 pm

GARY C wrote:
Mon Apr 15, 2019 9:37 pm
digger wrote:
Mon Apr 15, 2019 9:20 pm
RevTheory wrote:
Mon Apr 15, 2019 9:02 pm
Even DV's overlap charts, that I agree could probably use some better clarification, will get you well within the "squabbling over a couple of degrees" range of person opinion.

At least 128 gets you an LSA that would take dyno testing to improve upon, assuming it's used where it's supposed to be used. In a normal world, something like that would be welcomed.
Drip feeding info does not help.
Normally one post everything in the one spot so the equation and the assumptions or limitations with its use are known. Some of the early stuff presented made it sound like it could be used for anything and everything but now the horse has bolted.....
I will take you serious on that when you say the same to Jon and others that post little to nothing in this context.
do you have an example where they have done the same ?

GARY C
Guru
Guru
Posts: 5040
Joined: Tue May 14, 2013 10:58 pm

Re: Determining the correct valve opening and closing points

Post by GARY C » Mon Apr 15, 2019 9:51 pm

digger wrote:
Mon Apr 15, 2019 9:47 pm
GARY C wrote:
Mon Apr 15, 2019 9:37 pm
digger wrote:
Mon Apr 15, 2019 9:20 pm


Drip feeding info does not help.
Normally one post everything in the one spot so the equation and the assumptions or limitations with its use are known. Some of the early stuff presented made it sound like it could be used for anything and everything but now the horse has bolted.....
I will take you serious on that when you say the same to Jon and others that post little to nothing in this context.
do you have an example where they have done the same ?
1D... read the thread!

EDIT>>> Page 5 would be a good start. On the flip side do you have evidence of him ever giving any useful info to this subject?
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!

digger
Guru
Guru
Posts: 1459
Joined: Sun Jan 27, 2008 6:39 am

Re: Determining the correct valve opening and closing points

Post by digger » Mon Apr 15, 2019 10:45 pm

GARY C wrote:
Mon Apr 15, 2019 9:51 pm
digger wrote:
Mon Apr 15, 2019 9:47 pm
GARY C wrote:
Mon Apr 15, 2019 9:37 pm

I will take you serious on that when you say the same to Jon and others that post little to nothing in this context.
do you have an example where they have done the same ?
1D... read the thread!

EDIT>>> Page 5 would be a good start. On the flip side do you have evidence of him ever giving any useful info to this subject?
I use 1D myself. It's totally different scenario to what I was talking about.

Post Reply