CC Combustion Chamber Tips and Questions

[Indycars]

I stopped by the local "Regal Plastics" on a whim since I needed a plate to CC the combustion
chambers. I had no idea if they even dealt with the public, but it's usually not fatal
to try. They had a door labeled "Customer Entrance".....Hum looks good I'll try there first. They had
some example of some of the products they can make on site, they are not just materials but also fabrication.
He took me to the shop area to look thru the scrap pieces, there was plenty of the sizes in the range that
I needed.

Tip #1: Take cash for small purchases. They had a $10 minimum, but since I had cash, it only cost
$ 4.35 for what you see in the picture. Roughly 12 x 5.5 x 3/8.

Question: Once I got it home, I began to wonder if I should even cut it. Maybe it would be easier
if I CC'ed two chambers together. I know on a the scale of 1-10 of important questions, this rates
about a 2. Makes me wonder if you couldn't do all four cylinders, but you would need a different
plate for each type of head this way.

Oh well enough rambling, anyone try doing multiple chambers with one plate ???

Regal Plastic has multiple locations in the US.
http://www.regal-plastics.com/index.html

Tip #2: Get some old valves junk from your machine shop to protect the valve seats if you are going
to work on the combustion chambers, I plan on CC ing and polishing them. Since the 1.94" Intakes and 1.60 Exhausts
are very plentiful he gave a couple of each to see what I thought. It looks like these might
be helpful, but you can see how they don't quite cover the the 45 degree seat surface. I used
a Sharpie to identify the 45 degree cut. It's hard to see with all the shine.

Carter's Automotive Machine, where I took my pieces, said if I could wait a few days he probably had some junk
2.02 intakes and 1.60 exhaust or he could get some new cheap one for about $5 each. Looks like I
need some.

I will need to get really close the the seats to smooth out the sharp machine surfaces that will have a negative effect on flow and increase the chance of detonation.

 

[grumpyvette]

small block Chevy heads have a 4.40" bore center line, BIG block Chevy engines have a 4.840 bore center-line, so a section of that clear plastic about 6"-8" wide , and about 24" long with 4 holes drilled on a 4.6" bore center-line should work to cc either heads, or even better, you can drill two different lines of holes for each head center-line spacing in the clear cover plastic,along different edges, one set about 1" from either edge, and just use the edge that matches the bore spacing , your dealing with at the time as a 6"-8" wide section of clear plastic will have more than enough overlap, as it won,t make much difference when cc-ing heads

When you CC heads, BE sure the glass or lexan is not allowing some of the measuring liquid to seep out of the combustion chamber, under the glass or lexan , or the sealant between the glass is not being displaced into the combustion chamber, thus giving you a false volume.
(getting some sealant squeezed into the combustion chambers, or fluid leakage is (VERY EASY TO DO)
ID suggest looking carefully at both potential reasons for the variation in measured combustion chamber volume
so Id use a tiny bit of sealant grease (a bit of Valvoline works if you use colored water, with a drop of dawn dish was liquid to destroy surface tension) you'll obviously want to open up the smaller combustion chambers a bit, and un-shroud the valves and try to match the largest chamber size

BTW YOUR DOING FANTASTIC PHOTO/POSTING WORK!

viewtopic.php?f=50&t=4618&p=13240#p13240


BTW HERES SOME REWORKED BIG BLOCK HEAD COMBUSTION CHAMBERS

STOCK

SIGNIFICANTLY IMPROVED FLOW

 

[Indycars]

I knew it sounded good in theory, but you know how that goes some times. Reality says that
you might have trouble getting a good seal on all chambers at one time. I'll just leave my plate
uncut and do two cylinders at once.

Thanks for the dimensions that should make placing the holes a little easier!