gostopturn
gostopturn New Reader
3/1/09 5:15 p.m.

sitting here watching vegas race. they show a head to illistrate what happens when a valve spring breaks (nothing good, big suprise). what i found interesting was the way the combustion chambers had colored. they were carboned black in the area between the in and ex valves. however the rest of the combustion chamber ( the squish area?) was clean. no deposits, no color. i have no experence with high $ race engines, only modified street engines. on them the whole chamber will color. what am i seeing? only things i can think of is 1. the engine didn't live long enough to fully color 2. the squish areas get really close to the piston head or 3. intake and cyl head turbulence control have somthing to do with it. any other ideas?

Monkeywrench
Monkeywrench Reader
3/1/09 7:04 p.m.

It's a combination of several things..

Header design

Piston design

Intake ports/combustion chambers are designed for swirl to concentrate the air/fuel mixture at the right place.

Fantastic fuel atomization from the carburetors and a spot on tune.

Cam timing

Basically what you're looking at is $100's of millions worth of R&D to get to what you see. People say that porting a cylinder head is a "black art", well it's not. These guys are using dry and wet flowbenches, cfd software, clear cylinder heads, and some of the sharpest people you'll ever meet to get where they are.

IMO, www.speedtalk.com is the best cylinder head forum out there. A lot of the REALLY BIG names have left the site as it has gotten more popular, but dig through it and you'll find some engine building/porting gold.

Monkeywrench
Monkeywrench Reader
3/1/09 7:34 p.m.

Here are photos of the R07 cylinder head as taken out of the box.

http://www.darinmorgan.com/R07.htm

Here is the older design (which is still used by the Nationwide cars) http://www.darinmorgan.com/sb2.htm

DirtyBird222
DirtyBird222 HalfDork
3/1/09 7:49 p.m.

yea saw that too, how about those freakin' valve springs? No wonder those things can rev to 10k+

gostopturn
gostopturn New Reader
3/2/09 12:48 a.m.

monkeywrench. i've never seen semi finished heads before. do you now do initial port and chambers shapes from your best guess from previous heads or from something you've developed for theseheads from software?

Monkeywrench
Monkeywrench Reader
3/2/09 8:59 a.m.
gostopturn wrote: monkeywrench. i've never seen semi finished heads before. do you now do initial port and chambers shapes from your best guess from previous heads or from something you've developed for theseheads from software?

A little bit of both at first. Generally they are first designed by hand. As they start collecting ported heads, They'll make a CNC program and continue to develop them using CFD software and by hand.

When they actually make the heads they are using, they rough them out with a CNC machine and finish them by hand.

Here's a link of interest (though doesn't really tell a lot) http://www.dscohn.com/pdf/cgwcars.pdf

Monkeywrench
Monkeywrench Reader
3/2/09 9:37 a.m.

Here are some more SB2.2 photos (R07 photos are impossible to find) from a motor claimed to have run at Daytona in 2006.

1

2

3

Finally found something... here

Look at the finished exhaust ports vs. the as cast ports from my first post.

And for the technical changes in the R07 head vs the old, then look

here

And here is very interesting article comparing Nascar & F1 engines

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