Milwaukee Midget

[251ENG]

Hello all

Glad to be of help

Fordboy , would be interested to see how the valve sizes compare to port throat sizes and what secondary angles/radi have been cut either side of the valve seats .

Have you ever used CNC ported heads ?

[fordboy628]

Hello all

Glad to be of help

Fordboy , would be interested to see how the valve sizes compare to port throat sizes and what secondary angles/radi have been cut either side of the valve seats .   I am accumulating that info now and will post it after it is tabulated.    In general though, head pockets ported all the way to the base of the 45 degree seat, (both in & ex) flow poorly.   Heads with seats with a 'bottoming' angle or radius flow better.   People porting these heads need to read a book on airflow dynamics . . . . .

Have you ever used CNC ported heads ?    I would if I could get one!!    Have inquired to CNCheads.co.uk MANY times about price & availability of their LISTED heads for 'A' & 'B' series.     To date, NO RESPONSE.

 
Fordboy

[fordboy628]

Another mad scientist . . . . . . .[/size][/i][/b]

http://russellengineering.com.au/performance-cylinder-heads/

Thought you'd like Graham (Russells) Stuff F/Boy / Igor / ?

Yes.    What I especially like is:

A/   He is thorough,
2/   His conclusions fit in with commonly accepted liquid/air flow science,
d/   He is willing to share his knowledge on the internet.

I'm sure that he & I could come to a consensus on beverage choice . . . . . . .
 
Fordboy

[fordboy628]

Midget, et all,

Think you can "out engineer" these guys?

http://www.ricwood.com/facilities.html

Spend some time on the cnc & gasflow sections . . . . . . .

 
Fordboy

[jacksoni]

You have to remember (and I know FB knows this) that there is nothing really magic about CNC. You have to design, hand grind, flow, try again, fix, test, check velocities, grind more, put in engine, dyno it, test more etc etc until you go Eureka! this is it!!!. Then you digitize it and make the CNC machine make all the ports the same and make your fortune selling this CNC head to someone. You make a junk port and CNC it you have equally matched junk ports. Just because someone is selling a "CNC head" does not mean it will work better than someone else's hand ported or out of the box or whatever. And bigger, unlike in other things, is not always better. 

[Milwaukee Midget]

Spot on, Jack.

Mark called this morning - we talked about that.  What CNC does is provide a degree of repeatability to a production process that can't be effectively matched by your head grinding guy in the shop.  But given the inconsistencies and shortcomings of production castings, one's ability to repeat a process on a used head is wildly diminished.

Starting with a controlled, fresh casting, maximized for competition, built to your specs on a limited production run, eliminates a lot of wasted man hours getting a head just about ready, and then finding a water jacket.

This surprised be, but I figured a 5 port head done by hand would take about a day.  Fordboy told me I was nuts, and that he used to estimate three full man-hour days for an A-series head.  If a shop charges $100.00/hour, that's $2400.00 in labor alone, and if the casting is junk, well, let's start the process over.

At 2750 Sterling - 4500 American Dollars, you get a head that has been maximized without the compromises that a stock casting brings to the table.

I'm in too far already, but if I were to start this project over from scratch, I'd spend the money.  I have never regretted buying "good guy" parts.

 

[Jack Gifford]

Chris- looking forward to an essay on your cam analyzer session. Who makes the machine? Is it computerized?

[Ron Gibson]

I remember seeing an interview with Rusty Wallace when he drove for Penske. He said they spent $5,000,000 on cylinder head research in one year.

Ron

[Peter Jack]

I absolutely agree with Fordboy on his time estimate. I've ported a few cast iron heads over the years using a rather conservative approach and with access to a flow bench. Cast iron doesn't port very quickly and is really dirty. You need to wear full protective equipment for your eyes and breathing, use a vacuum system to get rid of most of the dust and provide lots of light. It's not a fun job so it should be charged out at higher than normal rates.

Pete

[fordboy628]

midget,

Cam in hand.

Portable cauldron packed.

Heads loaded.

Be in Beerhaven around 9 AM Saturday?

Luncheon @ ?

Now where might we find a friendly brewpub?   Hmmm . . . . . . . . . ?

 
Myrddin Emrys Flowmonkey, er, Cammonkey, er, babboona$$  

[fordboy628]

I remember seeing an interview with Rusty Wallace when he drove for Penske. He said they spent $5,000,000 on cylinder head research in one year.

Ron

You would be SHOCKED to know how many R&D dollars are spent by professional teams every year.    It's about gaining an advantage, regardless of how small the advantage might be . . . . . . . .

Did anybody notice Hendrick cars finished 1,2,3 @ Daytona?   Yes, they were lucky.   You have to be.   But you also need to be in a position to be ABLE to win.     Hendrick Motorsports has the BEST restrictor plate engine development program.    It has been that way for years . . . . . .
 
Fordboy

[jacksoni]

Don't remember where but some report they had given up looking for 1-2HP. Now they are looking for 0.5HP. 

[Milwaukee Midget]

"Great men, become great because they have been able to master luck. What the vulgar call luck is a characteristic of genius."
 - Napoleon Bonaparte

[fordboy628]

Fordboy , would be interested to see how the valve sizes compare to port throat sizes and what secondary angles/radi have been cut either side of the valve seats .

Initial results are:

Poor flowing heads:   88.7% to 91.6%   Usually ported to the bottom of the 45 degree seat.
Better flowing heads:  87.0% or LESS.   Typically have a bottom angle/radius below the actual valve seat.

There is not a lot of difference here, BUT, the difference is truly SIGNIFICANT.

The approach slope angle of the long side (upper/top of the port) radius is also VERY important.   Heavily ground ports with a reversed slope (very common) typically flow poorly . . . . .

To anybody who wants to port their own head(s)/block/etc:

A/   Read a book on fluid dynamics first.   (Yes, air is a fluid for our purposes.   It's just much less dense than say, BEER!!)   
2/   Fabricate or purchase some flow bench adaptors.    Just like the ones pictured a few pages back in the build diary, to suit your parts.
d/   Arrange for some flow bench time.    You will learn a lot.
z/   Start by flow testing un-modified parts first.    You will then be able to quantify any "improvement".    Don't be surprised by "negative improvement", 'cause it happens!
      There is a graph of a prime example, just a few pages back . . . . . . . 

If your tricked out head(s) don't flow what your engine demands, you need to bite the bullet and farm out the job.
 
Flowmonkey

[fordboy628]

More porting porn!!!!

So ya wanna port cylinder heads, eh!!

Making port core samples of a good cylinder head.



     What a mess!!   Sure hope the mold release works . . . . . . .                  Gee, what else would this be good for?
 
Foamyboy