How do they cc cylinder heads

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Dan the man

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I was thinking about how a machine shop cc's cylinder heads? Would milling the heads work?
 
Dan the man said:
I was thinking about how a machine shop cc's cylinder heads? Would milling the heads work?
Click to expand...
Do all the seat work, pick valves etc.. then measure and mill. Only sometimes do you end up milling 1st and that is because the seats are cut proud in the chamber 'not very deep' and so you would end up cutting into them some at say.. the 30 angle.
 
Cc'ing, in most references I've seen it, is measuring the combustion chamber volume, in cc's, and performing needed machining to reach a specified volume.Milling is one way to reduce that volume.
 
Dan the man said:
How can the combustion chamber sizes be equalized, say 2 chambers are 64cc and the others are 62cc how would you get them all to 62cc's? Can this be done?
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You gain in areas such as the parameter of the chamber 'tracing to the bore' or pushing the chamber edge out to the bore size...or you can skim the chamber around or on the plug side .
easy.
 
Dan the man said:
How can the combustion chamber sizes be equalized, say 2 chambers are 64cc and the others are 62cc how would you get them all to 62cc's? Can this be done?
Click to expand...
Yes, you open the chambers that are a little small, till they are all 64cc, then mill the head till they are all 62cc's, or whatever is desired.
 
MOPAROFFICIAL said:
You gain in areas such as the parameter of the chamber 'tracing to the bore' or pushing the chamber edge out to the bore size...or you can skim the chamber around or on the plug side .
easy.
Click to expand...
Thanks for explaining that to me. I may ask the machine shop what the cost is for this. I'm most likely going to buy bare cylinder heads that way I can have the guides done, valve job and spring height done
 
Cubic Centimeters of liquid. So 50/50 of ATF and mineral spirts and a graduated beaker is how they are measured…
 
Scody21 said:
Cubic Centimeters of liquid. So 50/50 of ATF and mineral spirts and a graduated beaker is how they are measured…
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I'm pretty sure that a friend of mine has one of those, I know that he would let me borrow it. He's into all the "small " details of engine building. He likes to get what free / cheap horsepower he can. Back in the day he couldn't afford to buy a stall converter for his turbo 350 so he used a converter from a powerglide.
 
Mostly, the final step in attaining the desire chamber volume/cc...is the grinding part.
More often than not you can mill after opening them.. and find they're out of whack again/variances. It's not a perfect circle or coffee can. When not completely uniform..they can and will be different sizes when you're done milling.
 
The more people/shops I speak with...the more and more I'm finding people dont aim for perfection. 1cc out means maybe .2 hp if that..its not something many builders worry about. Many dont fret over up to 10lbs variance in spring pressures...they dont care about 15 cfm spreads... or bringing the quench in equally across all 8 etc and so on. In the end "the power diff is only chased by championship teams" ...etc
They only care about it not coming back. Good enough to stay together is moto...I guess. I tell them I dial this and that within a Knats *** crack..and they smile and say... "that's a lot of work for very little gain"
 
This is how I did it at home. It was inexpensive and easy! After measuring each chamber you can simply remove a little material on the combustion chambers that are too small (lower ccs) until they match the largest ones..

 
You can use a a cd case with the edge cut off to lay flat and some grease to seal it...and water. Just do the conversion from cup/oz to cc
 
My daughter-in-law is a nurse........everyone knows a nurse, I had her bring me a large syringe. That worked perfectly!!! I piece of plexiglass, some grease, clean surfaces and you're good to go!! It's actually very, very easy.
 
I think you have your answer on how they CC heads.
The head needs to have the correct valves and the valve seats finished.
There are formulas for milling heads to reduce CC by a approximate amount.
The time to CC each chamber is what eats up the clock.
And then after to you have your numbers, going back and grinding to equalize.
Getting close to calculate compression ratio is good enough for most engines.

Now racing engines is another story.
 
Dan the man said:
How can the combustion chamber sizes be equalized, say 2 chambers are 64cc and the others are 62cc how would you get them all to 62cc's? Can this be done?
Click to expand...

First, start with clean heads with valves seats ground, and with the intake and exhaust valve you will be using. With the head slightly off level, use grease to seal a flat plexiglass plate with a hole at the top where the last air bubbles will try to escape. Use a syringe or burette and measure all the chambers. Write down your the volume of each chamber volume. Calculate how much material you need to remove to get to your desired chamber volume. Mill heads that amount, and I mill the intake side of the head the calculated amount to keep everything in the right relationship. To equalize the chambers, I simply polish the chambers till they are equal or within .1 of a cc.
 
Not hard.... I even did it. I went down to TSC in the horse aisle and got me a 60cc syringe for like $8 (had to buy a 2 pack) and a piece of plexi, I already had vaseline here for the grease "seal" between the plexi and the head, and I used what I had here, "purple power" windshield washer fluid/ though on my /6 the 60cc was a bit over the capacity I needed..... for a V8 you might need a bigger syringe. you dont want to have to refill halfway thru a chamber. mine came out 48-49cc. again this was a 225 cid /6. but the process is the same.
 
Treblig said:
This is how I did it at home. It was inexpensive and easy! After measuring each chamber you can simply remove a little material on the combustion chambers that are too small (lower ccs) until they match the largest ones..

Click to expand...

You beat me to it. CCing heads is simply making all the combustion chambers equal in volume. Find the largest one and make all the rest the exact same volume with grinding or polishing. I would think you'd have to be pretty darn careful how you did your material removal.
 
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