i want to figure the compression change with a few factors of a motor.. and i have the formula, i just dont have some of the numbers to plug into the formula...

all the numbers i need are from the L03 305 TBI motor, what i need is the stock deck height, stock head gasket thickness, stock dome height on the pistons (negative number i think? -6cc or -8cc... not sure, thats why im asking hehe), and the bore of the pistons. is it 3.74" or 3.75"?

thanks

 

nm...

 

pistons ought to be .025 or so in the hole, gasket is around .040, damn i ought to know deck height but i can't think of it right now, 9.23 maybe? bore is 3.735, i think the dish is 6cc but again i'm not sure. sorry i couldn't be of more help i'm getting old and it's hard to remember my own phone number sometimes.

 

lol its ok, thanks for the numbers though, its a good starting point

 

this is making me p/o now lol i think i have the compression formula wrong..i got it on the boards here in a search i think, now i cant find it, some knowledgable person posted it... this is what i have, itd be great if someone can fix it if its wrong or tell me what im doing wrong? im just trying to get the compression right for a stock L03, so i know that im doing it right. i should be getting around 9.2/9.3:1, but im getting more like 10.8:1 and 11's and even a 1.46:1 im doing something wrong.


cylinder volume: bore x bore x stroke x .7854

(something with the deck? i think it was deck height, this might be where im wrong): bore x bore x .7854 x deck height

head gasket thickness: bore x bore x .7854 x gasket thickness

head volume: volume cc x .061

dome height: volume cc x .061



once you figured that, you plug it into this:

(cylinder volume + deck height + head gasket thick + head volume + dome volume) divided by (deck height + head gasket thick + head volume + dome volume)

i think i have the formula wrong? i cant find the post and ive been searching lol