cylinder head machining

[64clubwagon]

I have a question on how to tell how much material has been machined off a head?
I have a '66 170 in my club wagon and want to swap on a fairly fresh '77 head
that I did some horse trading for. I also know that with the new head gaskets
and a '77 head that my compression ratio can drop nearly 1 point. I know that
the head has been milled but no idea of how much. Does anybody know if there is
a point on the head that is for reference that I can measure with a micrometer
to tell home much material has been removed.

Thanks,

Ken

wayward in Hayward, CA

 

[JackFish]

Yah it's called cc'ing the head. "cc" stands for Cubic Centimeters.
You will measure with a liquid of some sort.
Some folks us ATF or clear oil, or whatever oily stuff suits your fancy.
You have to get a piece of plexiglass to cover the cylinder with, and drill small hole into which you'll put the liquid. Some folks use a fancy burette, but I found graduated syringes from the drug store work OK, just not as finely accurate.
So after the glass is secured on the head you'll measure the liquid as you put it into the cylinder through the hole. The head must be level, of course.
Chamber volumes of 200 cubic inches = 3.3l divided by 6 = 55cc range or less if it's been shaved.
Roughly....

There are some utube videos and websites with photos and explanations far better than mine.

 

[64clubwagon]

JackFish,

Thank you for the reply but I am aware of cc'ing. I was hoping that there was a method/reference point that I could use a micrometer on ( I have several in my toolbox ) and knowing what the thickness should be verses what I measure I'd know the actual material removed.

ken in Hayward, CA

 

[chad]

JackFish,
Thank you for the reply but I am aware of cc'ing. I was hoping that there was a method/reference point that I could use a micrometer on ( I have several in my toolbox ) and knowing what the thickness should be verses what I measure I'd know the actual material removed.
ken in Hayward, CA

Hi Ken,
the method U suggested would not work accuratly due to changes in the 'bowls' beyond just a 'shave'. It wouldn't reference as well as a direct measurement I don't believe. With an unknown Y not get acurate? pretty easy...how bout a lill window glass that is just big enuff for a cylinder? pour some in, eye ball it, when close (to avoid 'surface tension' effects) slap the glass on??? May B try the vid jackfish may B able to cite 4 U...
Good luck, stick w/us = no longer wayward in hayward

 

[MPGmustang]

the 77 head had roughly 67cc chambers, you'll have to cc your head to figure out much has been removed, a VERY rough rule of thumb would be 1cc= .0067 inch, but like others have mentioned, the shapes of the chambers differ at diffrent levels, and you'll get very diffrent volumes the more you take off.

I recomend only removing .020 at a time, if using a felpro gasket you'll want 50-52 cc chambers for a 9.1 CR, use http://www.falcon6handbook.com/compcalculator.asp and play with the numbers with your specs to figure out what size you need.

if you cut too far, you can unshroud some of the valve from the side wall of the chamber, and if it's extremely too far, start polishing, but first CC the chambers, not every chamber will be equal, most cases the 1 and 6 are a little bigger than 3 and 4, so you have to cc every chamber one at a time. take you time, do it right once and then never worry about it agian.

Good luck and if you have more questions just ask, it's better to have more questions than a skinnier wallet

 

[chad]

",,,77 head had roughly 67cc chambers..."
& that's for the '77 170?