How to CC a combustion Chamber
 

How to CC a Combustion Chamber

The subject head is a Chevy LT1 Head

The first set up is used when the valves do not protrude above the gasket surface.
This is simple in procedure. Fill the CC burette with a fluid, I use water, some use a color alcohol, cover with the sealing plate, then flow the fluid through the hole in the seal plate till all air bubbles are out of the combustion chamber. Then read how much fluid has flowed from the burette.
This stock head measured 54cc
https://www.miataturbo.net/attachmen...ine=1332339322



The second set up is used when the valves do protrude above the gasket surface.
This is a little more difficult in its set up.
Since the valve heads protrude above the gasket surface, the seal plate can not be used, I use my dial indicator with a point, The indicator must be zeroed, with no pre load to the deck surface. Once that is done it is a matter of leveling the head and filling the combustion chamber just till the fluid touches the indicator point. Then read the burette.
This LT1 head measures 49cc
https://www.miataturbo.net/attachmen...ine=1332339322

Alcohol would have given a more accurate reading with this method, since alcohol does not “dome” like water.

You could also think about using a distance ring with the bore id together with the seal plate. Then you include the protruding valves in the volume (good/bad/ugly?).

Nik.. that would work too as long as you knew the given volume of the ring