Shon Herron

This would be a better starting point. Oh well.....
On a side note, went to the track to watch last night, the LT1s out there are a disgrace, slaw as ****, cammed LT1 car running 85MPH and even had the benefit of spinning off the line.....

Javier97Z28

lol... there's so many garbage LT1 cars out there it's not surprising we get a bad name.

So many high 14 second cars now owned by dumb kids...

airflowdevelop

Gary,
You are correct in the theory that some areas in the port are less critical than others. What specifically are you looking for? What areas that are critical to keep to these tolerances? How I measure to verify this?

You don't really have to beat around the bush with me...ask exactly what you are thinking...and I will do my best to answer honestly. I don't believe in keeping "secrets" from the customer.

I will provide a brief overview of what happens on the average head that comes into the shop.

1. Guide centers on one port are located and measured

2. Valve job is roughed in, withing .020 thou of finished height

3. Top of throat angle is cut to pre-calculated size. Form tool is set with micrometer fixture, and reverfied after cut, with either an inside mic, or dial calipers.

4. Intake port location is indexed to bolt centers of intake.

5. Now comes the hard part. After a look at the core, and some math, I come up with a first shot gameplan including the sized that I want particular ports to be. I setup some snap guages to .020 smaller than those sizes, and start cutting. Back and forth of the bench, watching airspeed, at this point I have a good idea of what it should flow, just making sure to keep the port smooth as far as airspeed is concerned.

6. Once the port is about where it should be, then it becomes time to "tune it up". This is done with 60 grit cartridge rolls. I will mow off the .020 I left in the port, starting with the less critical areas. You can setup some snaps, as go no-go guages. I like a couple thou spread, and work areas like the fast wall to keep them as flat as possible..no low spots. Obviously, critical areas get more care, and we will go back to the flowbench as necessary to tune up the SSR's and throat, or an area of choke, if it exist.

7. Finish valve job. Last time on the bench.

8. Port gets digitized, and then duplicated.

So up to this point, I guess everything makes sense...right. Number 8, is a comfort option...Some heads do not go through this number 8. They go through many hours of 5,6,and7 repeated 7 more times...or how ever many ports we are dealing with. I guess your main concern is how trustful you can be that your porter will do 5,6,7 again and again...not get tired...lazy...or want to screw you over by giving you one great port, and 7 turds.

9. All cylinders are verified to be equal within a pre-determined amount of flow / airspeed.


...so here we are...cylinder to cylinder...very accurate heads, port to port.

I hope I answered your question?

airflowdevelop

But do we want all ports to be exactly the same? ...that is the real question? Who cares if we have 8 exact copies of each other...Do we NEED 8 exact copies....riddle me that?

Dennis

Z-RATED94

My guess would be no. But then again I would think what type of intake manifold your running would play a part in this. And if you don't mind me asking (I know it has been mentioned) which cylinders are the ones that run lean, and are there any that run a little fat with a factory intake. Also, what might a porter do to help compensate for this? Thanks Dennis, Rick.

IllusionalTA

Must have been the humidity... and probably installed the cam upside down.. not to mention majority of these kid's are misguided..

OldSStroker

Not if we treat the engine as eight single cylinder engines running on a common crank. Most of that kind of thinking is probably at the higher end stuff. Cup comes to mind.

airflowdevelop

exactly...when you are that far into it...especially with certain manifold designs (centrally located inlet, and lateraly located inlet), it becomes imparitive that you treat the motor more like 8 briggs instead of 1 v8.

Dennis

airflowdevelop

Gary,
I don't know what cylinder head guys you hang out with...but .015 is a football field. Also, do not confuse street car heads with race car heads. I am going to spend a couple hundred hours on a manifold or set of heads for the average street guy that has a grand to spend...NO. But in the industry, do people spend this much time making everything perfect...YES! Infact, a number of people have started doing portwork with and only with a torque plate installed!

Also, all master ports are digitized. I can tell you the location of any point in the head you want to know...and cylinder to cylinder.

Dennis

airflowdevelop

Also, as much as you have been around this stuff...have you seen any of Foltz's handy work? Thats super human grinder skills...

Dennis

Dan Parker '96

I vote for "Best Pissing Match Ever".

Who has the biggest bladder?

nosfed

I just skimmed all 19 pages of this thread and I have to say that Bret and Joe O really need to take their childish bickering to PMs so the rest of us can have a civil discussion and maybe learn a thing or two. After seeing you two trash this thread I can't imagine I'd ever buy anything from either of you. Neither of you seems to care that some of us are here to learn, and your pissing contest will stop that from happening when the thread is locked.

On the other hand I really appreciate Dennis stopping by this board to share his knowledge. It's a real treat to learn from guys that really know their stuff. I've been a gearhead since I was a kid, so guys like Dennis are celebrities. Also, thanks to the other level headed machinists that contributed in a productive way.

I've had some work done by Lloyd (SB2 intake and SBC heads) and his work is as good as the average person can get, and the price and service are unbeatable.

There should be a back to back test of AI and LE head cam and intake packages. How hard could it be to put a package from each company on a flat top 355 and strap it to a dyno? Just be sure both packages were designed for that setup and that the builder didn't know the package would be used for this test. I have a brand new 355 short block I'd offer, but it has -26cc pistons.

airflowdevelop

Gary,
What is your background? To be frank....it is pretty obvious that you have little knowledge of what goes on in the real world. As I sometimes need to say to "new" HP customers...."DISCONNECT YOUR COMPUTER, AND PUT THE MAGAZINES DOWN NOW"!

Serdi's are great machines for production shops. It is possible with the right equipment, to cut a fairly true seat with a form tool cutter. But for serious HP stuff, It is almost ALWAYS a benefit, to cut your seats .005 short of there destination, and sharpen them up with a stone.

Even in industrial machining, there is no such thing as a "precision cutting" machine...but I am sure you have heard of "precision grinders" before. If you have a properly prepped stone, and the correct skill, you can polish the fur on a fly's ***.

I am not sure why you find it necessary to question everything that anyone says, if the reason is because you would like to learn something...then stop typing, and starting listening. As the old saying goes, you can never learn anything with your mouth open.

SStrokerAce

Wow, you still cease to amaze me with your BS Gary. I'm gonna have to look up a dummy smilely for you.

Bret

SStrokerAce

Gary, you never know till you see it obviously. I doubt you ever will.

have a good weekend.

Bret