cylinder head,porting,& blending questions - Chevelle Tech
Chevelle Tech join team chevelle as a supporting member  
Chevelle Parts at SS396.com      
GROUND UP & SS396.com         
Official Sponsor of Team Chevelle
     

Auto Insurance

Chevelles.com is the premier Chevrolet Chevelle Forum on the internet. Registered Users do not see the above ads.
Performance Our High Performance area

Reply
 
Thread Tools Search this Thread Display Modes
  #1  
Old Jan 5th, 10, 10:02 PM
cheveezies cheveezies is offline
Team Member
tommy
 
Join Date: Mar 2008
Location: ont can
Posts: 274
Default cylinder head,porting,& blending questions

i'm looking at porting , bowl blending & checking combustion chamber volumes . i have bought two video's , an air die grinder , carbide tips , stones & sandpaper rolls , & a flask/buret to check combustion chamber volumes , from summit , with '' no '' instructions . rookie questions . 1. do you put the valves in , then add oil or water ? . i realize the plexi plate has to go on first . 2. do you do the bowl blending before checking volumes . 3. i've read on one post a fellow offering services on porting & blending . he asks the customer what c.c volume are the heads now . what is the compression rated at . what pistons , & other questions ? . this seems to be important info needed to decide on what route to go about the particular heads . my question is : once you have this info , how do you decide what needs to be done ? . it would be a good thing to know , if you done your own heads properly , you could tackle your buddy's or show him how . the tapes i have do not show or explain these procedures . only porting , polishing & bowl blending . any info back much appreciated
__________________
Tommy's Toys
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2  
Old Jan 5th, 10, 10:10 PM
lun40119 lun40119 is offline
Senior Tech Team
Jake
 
Join Date: Jan 2010
Location: Appleton, WI
Posts: 1,451
Default Re: cylinder head,porting,& blending questions

I would practice on his
__________________
Jake
Reply With Quote Quick reply to this message
  #3  
Old Jan 5th, 10, 10:24 PM
Ben Lurkin Ben Lurkin is offline
Tech Team
 
Join Date: Sep 2009
Location: Oquirrh Mountains
Posts: 94
Default Re: cylinder head,porting,& blending questions

Not sure what you mean by porting, but I would definately recommend you do no more than blend the bowls, clean up the castings in the runners, perhaps match the intake gaskets and a short-side radius on the exhaust ports. If you're not sure how to do this then don't.

Unless you have a stack of castings to experiment on and a flowbench to measure your results, you will likely end up with heads that flow worse than what you have now.

Good Luck.
Reply With Quote Quick reply to this message
  #4  
Old Jan 5th, 10, 11:40 PM
cheveezies cheveezies is offline
Team Member
tommy
 
Join Date: Mar 2008
Location: ont can
Posts: 274
Default Re: cylinder head,porting,& blending questions

thanks for the info guys . i am determined to learn this part of the trade & to do it properly . the first set of heads i am working on are b.b mopar heads that has one of the heads already ported in the intake runners . i am going to match the other head up to it . i also have the videos of porting & polishing the intake runners , & bowl blending showing just to clean them up , deburring & a bit of polishing . - not grinding the hang out of them , showing you what to do & not to do . the reason i bought the buret was i cant find any info , neither can the rep , on the c.c volume since he needed the info before ordering pistons - 383 mopar . i don't think i'll mess em up . second set is g.m 290 heads . after that it's new arp's for the beauvelle . - which i definetly wont be messing with . as i menthioned in my earlier post , it shure would be nice to know how to go about checking the cc's with the new buret i bought , & also so as i can tell the rep what they are , to buy pistons for this engine . any info back appreciated
__________________
Tommy's Toys
Reply With Quote Quick reply to this message
  #5  
Old Jan 5th, 10, 11:53 PM
RB69SS396Conv RB69SS396Conv is offline
Senior Tech Team
 
Join Date: Apr 2003
Location: SW OH
Posts: 3,352
Default Re: cylinder head,porting,& blending questions

To check the cc's, put the valves in; smear some grease on the seat; smear some grease on the deck, and stick a CD to it (an old "free AOL" one is about perfect, or one of those clear spacers you get when you buy a spindle of recordable ones); fill the buret up with anti-freeze/water mix, so the color helps you see what you're doing; and fill the head out of the buret. What it held when it started, minus what's left after you fill the chamber, = the cc's.

About 70% of the gain that a home porter can achieve without screwing up a head, is in "bowl blending". That consists of smoothing out all the wierd angles where the factory jammed the seat cutters into the cast throats. The next 20% or so is in smoothing out the roof of the intake port around the valve guide; smoothing, not "opening up". The goal is to smooth and guide the air as it rushes in and hits that spot and gets redirected downwards toward the valve. Another 5% or so is in smoothing the "short side" radius, especially the exhaust, WITHOUT lowering the port floor. The other 5% is in EVERYTHING ELSE. "Gasket matching" is mostly monkey-spank, mostly done to impress people who don't know what they're looking at, with some "eye candy" in a conspicuously visible place. Personally I can't be bothered with that, too much work with no payoff.

Removing sharp edges in the chamber is highly worthwhile. That reduces any tendency toward detonation (something that's already a problem with those heads). Especially, smooth the sharp edge where the chamber walls meet the deck, all the way around.
Reply With Quote Quick reply to this message
  #6  
Old Jan 6th, 10, 12:04 AM
Highway Star Highway Star is offline
Team Member
Jake
 
Join Date: Nov 2007
Location: Louisiana
Posts: 7,229
Default Re: cylinder head,porting,& blending questions

monkey-spank
__________________
1972 Malibu Sport Coupe
Holley Edelbrock GMPP Howards Melling Accel Taylor B&M Hedman Thrush Cragar

I do all my own stunts.
Reply With Quote Quick reply to this message
  #7  
Old Jan 6th, 10, 12:36 AM
cheveezies cheveezies is offline
Team Member
tommy
 
Join Date: Mar 2008
Location: ont can
Posts: 274
Default Re: cylinder head,porting,& blending questions

man ! that's what i needed . thank's alot RB69SS396CONV . great info
__________________
Tommy's Toys
Reply With Quote Quick reply to this message
  #8  
Old Jan 6th, 10, 12:39 AM
kirkwoodken kirkwoodken is offline
Senior Tech Team
Ken
 
Join Date: Sep 2005
Location: Missouri
Posts: 2,530
Default Re: cylinder head,porting,& blending questions

Dave Vizard's book can be found here:

http://www.alibris.com/booksearch?qw...*listing*title

It is slightly out of date, but will cover the rudiments of pocket porting, back cutting, throat percentages, and the like.

One of the most important things, I think, is to get some aluminum sheet stock that you can use for making templates so you can make all shapes the same. You want to make some patterns that have a "finger" that you can stick into the valve guide, and cut the template so it conforms to the inside, outside, and long side of the bowls. Make those for the intake and exhaust. Make some more patterns to fit over the outsides of the exhaust ports so you can make the short side floors all the same. Same with the long sides. Same for the port floors and roofs. You want templates for the ski hump on the short side.

If at all possible, try to find a well worked head, and make templates from those.

Write or call one of the flow bench companies and have them send some literature on using their products. Find out what tools you need to start out cheaply.

Dwyer instruments makes a lot of airflow checking tools. Can be found here:
http://www.dwyer-inst.com/

I would see if you could get one of their catalogs and some of their reference manuals.

Some of the gauges you need can be made from plastic aquarium hose and filled with colored water. Some of the measurements you will be making do not need absolute values, only need to tell if airflow is faster or slower in one area of the port.

Some people use a small, like 1/4", Styrofoam ball with a piece of thread through it attached to small wood dowel to see how air is flowing faster or where there is turbulence in the port.

The idea is to just play with all that stuff for a while, and you will see how adding some putty to a spot will change flow, add or remove turbulence. The goal is to get the air to flow through in a straight line without being turbulent.

Next thing is to hang out over on SpeedTalk and look through the archives about head porting. There is a ton of math on that site pertaining to airflow. You must know that to be successful at porting.

Just remember that all the porting is done by human beings. They live and learn, and that is what you must be willing to do. We can all do the same stuff if we are willing to prepare ourselves for the task.
__________________
kirkwoodken
406 SB, Original Bill Thomas '63 Rochester FI
AFR 210, Lunati 501C2LUN, 255/263@.050", .628"
10:1, TH400, 3.31's, 4400 SS

"Life is too short to not run a solid roller cam."
"Nothing is impossible; if you don't know what you're talking about."
Kirkwoodken
Reply With Quote Quick reply to this message
  #9  
Old Jan 6th, 10, 12:40 AM
Camaro_fever68 Camaro_fever68 is offline
Senior Tech Team
Ray
 
Join Date: Nov 2005
Location: Baton Rouge, La
Posts: 2,039
Default Re: cylinder head,porting,& blending questions

Quote:
Originally Posted by RB69SS396Conv View Post
To check the cc's, put the valves in; smear some grease on the seat; smear some grease on the deck, and stick a CD to it (an old "free AOL" one is about perfect, or one of those clear spacers you get when you buy a spindle of recordable ones); fill the buret up with anti-freeze/water mix, so the color helps you see what you're doing; and fill the head out of the buret. What it held when it started, minus what's left after you fill the chamber, = the cc's.

About 70% of the gain that a home porter can achieve without screwing up a head, is in "bowl blending". That consists of smoothing out all the wierd angles where the factory jammed the seat cutters into the cast throats. The next 20% or so is in smoothing out the roof of the intake port around the valve guide; smoothing, not "opening up". The goal is to smooth and guide the air as it rushes in and hits that spot and gets redirected downwards toward the valve. Another 5% or so is in smoothing the "short side" radius, especially the exhaust, WITHOUT lowering the port floor. The other 5% is in EVERYTHING ELSE. "Gasket matching" is mostly monkey-spank, mostly done to impress people who don't know what they're looking at, with some "eye candy" in a conspicuously visible place. Personally I can't be bothered with that, too much work with no payoff.

Removing sharp edges in the chamber is highly worthwhile. That reduces any tendency toward detonation (something that's already a problem with those heads). Especially, smooth the sharp edge where the chamber walls meet the deck, all the way around.

Good Post
__________________
Ray
Reply With Quote Quick reply to this message
  #10  
Old Jan 6th, 10, 2:12 AM
oxliver oxliver is offline
Tech Team
jason
 
Join Date: Jan 2008
Location: australia
Posts: 173
Default Re: cylinder head,porting,& blending questions

theres a dvd on ebay for 11 bucks . port and polishing it also has valve seeting on it aswell . not sure of the quality of it . would be a start
Reply With Quote Quick reply to this message
  #11  
Old Jan 6th, 10, 7:47 AM
tt 383 tt 383 is offline
Tech Team
 
Join Date: Oct 2008
Location: usa
Posts: 329
Default Re: cylinder head,porting,& blending questions

"Gasket matching is mostly monkey spank", I will agree for the most part, but some heads like the production Magnum head respond very well to a gasket match on both I/E ports. Not all heads are the same and respond differently to certain porting steps. Pushrod pinch usually not worth the time either, but also something that on certain heads can be a dramatic improvement. I only mention this because it sounds like OP will be doing multiple types of heads.
Reply With Quote Quick reply to this message
  #12  
Old Jan 6th, 10, 10:04 PM
cheveezies cheveezies is offline
Team Member
tommy
 
Join Date: Mar 2008
Location: ont can
Posts: 274
Default Re: cylinder head,porting,& blending questions

thank's alot for the info guy's . much appreciated . jason ; i've bought two videos through e - bay , the one is garbage . the guy's lighting is terrible . the second one is much better , but what they basically show is the work end of it , not the tech info like rb69ss396, ken & tt 383 have explained .
__________________
Tommy's Toys
Reply With Quote Quick reply to this message
  #13  
Old Jan 6th, 10, 10:37 PM
Busted Knuckles Busted Knuckles is offline
Senior Tech Team
 
Join Date: Dec 1998
Location: Lubbock, TX
Posts: 3,459
Default Re: cylinder head,porting,& blending questions

There is often a ridge around the valve seats that needs to be removed. It adds a lot of turbulence, particularly at low lifts. My engine guy uses a cutter that smoothes this ridge at the same time as the valve job.
__________________
Gary Adrian
FCS Harmony Racing

'Cause if they catch you in the back seat trying to pick her locks,
They're gonna send you back to mother in a cardboard box...
You better run!
Reply With Quote Quick reply to this message
  #14  
Old Jan 6th, 10, 10:40 PM
Highway Star Highway Star is offline
Team Member
Jake
 
Join Date: Nov 2007
Location: Louisiana
Posts: 7,229
Default Re: cylinder head,porting,& blending questions

This thread might help because there are all KINDS of progress pictures and opinions. Great read...but in order to see the pics, you may have to register.

http://www.thirdgen.org/techboard/te...-pictures.html
__________________
1972 Malibu Sport Coupe
Holley Edelbrock GMPP Howards Melling Accel Taylor B&M Hedman Thrush Cragar

I do all my own stunts.
Reply With Quote Quick reply to this message
  #15  
Old Jan 6th, 10, 11:45 PM
OutCast OutCast is offline
Senior Tech Team
John
 
Join Date: Mar 2006
Location: Vancouver Island, Canada
Posts: 4,126
Default Re: cylinder head,porting,& blending questions

I worked over my 781 heads for the first time attempt. I used an olive style carbide bit in my air grinder, with the air turned down to about 40 psi, so I could hold it wide open, and not rev too high.

Working one head at a time, I would spend similar time in each port, getting the entire head ported progressively at the same pace. I found it easier to concentrate on several small steps, rather than trying to start and finish one port at a time.

DrJperformance is a member here, and has a great website and can provide you with additional excellent advice and the carbide bits. His name is Bryce.

Practice on a junk head to just get a feel for the way the carbides bite. Once confident, move on to the real deal. I spent about 8 hours on each head. Probably take me 2/3 the time on the next set.

Make sure you wear good eye, ear and breathing protection. That stuff gets everywhere. Little iron bits in the eye can blind you, and in your lungs will make you feel sick.

It's a very rewarding experience to do. Just take your time and have some fun.
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
Reply
Chevelle Tech > General Tech Area > Performance      Current Topic: cylinder head,porting,& blending questions
Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Chevelle Tech forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address. Note, you will be sent a confirmation request to this address.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.



Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -4. The time now is 5:34 PM.


Is there a site like this for?    El Caminos Camaros Novas Impalas GTO Chevy Punch All Chevys

2009 Team Chevelle - AutoForums