I just did the CC for my head and bore and need
to have it checked to see if I'm right(getting
old sucks)
bore= 4.040
stroke= 3.79
I did the 1/2" down method and came up with 0cc
gasket dia= 4.170
gasket thickness= .044
true bore dia= 4.063
head CC= 65cc
zero deck with dome but came up to 0cc total
after the dishes
I came up with 11.78 compression


I use to run this engine with W-2 heads but I
will be running W-5s now.. looking for the comp
ratio
thanks

mike perfect volume for a 4.063 bore at 1/2" down is 106.23

What did the measured vol. come to? the difference will give you the dish vol.

I came up with 101cc(thats with the dished and the dome)
so I can add a bit more to my numbers

so you have 5.23 cc dishes.

head = 65
gask = 9.8
dish = 5.23

total = 11.06:1 is what I got after I adjusted the gask vol.

I came up with 11.10 on the comp with the new
numbers... I will be running this on pump fuel
and I dont want to pull a ton of timing.. this
is with injection

I'm sorry Mike my gask vol was wrong! I changed my post to 11.06:1.
We got about the same thing.
Been a while since I did it also. I cheated I went and got the engines book.

Don

Its all good... thanks for the check.. guess I
will have to deal with it

Guys, maybe I read to quickly but, If perfect vol. is 106.something and you poured 101 to fill You need to subtract that difference from the vol. numbers. You are taking up chamber space.

I agree. Mike, sounds like a 5.23cc DOME, not a dish. If there was a dish, you would measure more than 106cc with the piston down .5". You are measuring 101cc with the piston down .5", right?

I get about 12.57:1 CR using the dome number:

Head: 65cc
Gasket: 9.85cc
Dome: -5.23cc
Total Chamber (TDC): 69.62cc
Cylinder Displacement: 805.21cc
Total Volume (BDC): 874.83
Static Compression Ratio: 874.83 / 69.62

Damn.. and I just put the heads on.. I guess when I get
back from vacation I will mill the domes off and do a
balance.. damn.. but thanks guys.. I want this to run on
pump crap

P what about milling the domes & ordering some custom heavy piston pins to make up the weight? At least the eng could stay put.

This is no big deal.. its on the stand.. the
Rampage had the W-2 in it now... I could even
change the program to E-85 but its not that
easy to find(its just not at every station
but it is around the area)

If you are running aluminum heads you should not have any problem running super unleaded gas at that compression. I have never ran anything but pump gas in my motor at 10.9 comp. I have not had any issues for 5 years.

Right now I'm at 12.5... thats to much

OOPS

I did a little checking.. the dome is .075 tall
and IF I mill that off I would have to re-balance
the crank.. to mill it 2.8 cc per gram(I dont know
how many grams .075 is worth) but was gonna weigh
it then mill and weigh it again... OR leave the
pistons as is and look at thicker head gaskets to
get it down to 11 to one.. that way I dont have to
re-balance.. but either way would cost about the same
EDIT
Nope.. wont work in my head.. I would have to add
more intake gaskets due to the head gasket change..
so I'm back to milling the domes off and do a balance
job