Lost CC

Here is my question, where am I loosing the CC. I ordered new pistons gave the manufacturer my motor information, 4.465 bore, 4.25 stroke, chamber 117.5, gasket 4.520x .063. i wanted 11.5 comp ratio. their program told them a dome of 34 cc. when i got the pistons, the dome looks about the same as other manufactures i have for the same compression ratio, I ironically i have a probelm with that motor where it appears the compression is too high. I cc the dome came up with 28 cc, they said they did also and come up with something like 33cc, so i will use their numbers
My computations

Head chamber 117 cc
Piston dome less 34
sub total 83

Gasket volume Plus 16.3

sub total 99.3

Piston in bore volume .020 5.1

computed volume 104.4
this is close to what it should be.
I assembled the pieces, then rolled the motor over and filled the chamber to check the compression. It held 91 CC, which is 13.5 compression ratio, filled the cylinder MANY times and came up with the same 91cc. I figured I must be doing something wrong, so I called another shop to have them check it. I took the motor to Oddy's Automotive, Billy Leverentz was out standing, he stayed late waiting for me then we filled the chamber while i was there at 9:30 PM! He came up with the same 91 cc.

So where is the extra volume difference between the computed 104.4 and the actual 91cc?

 

in the hole

ooops .020

i screwed with it with the programs on line. I am not even thinking of the compression ratio at this point, i am just trying to figure where the CC went!!

the end result is I am concerned with the compression ratio.

 

grease

i was thinking at the time i was using a lot of grease, and i was thinking i allowed for that, but i will do another cylinder and actually measure it. thank you

 

What about not using grease and putting a o-ring in the ring groove instead ? .

 

still lost

used the grease filled either side of the spark plug where it looked like it might catch air.
I used a used gasket that measures .084, so i am thinking it is a compressed .093.
CC=98 or 12.12:1

Called Hassel in PA they can make me thicker gaskets for $130 each or $260 a pair and 2-3 weeks.
need to have it running the 30th