Rob Dizzle

I am trying to figure out if displacement would change if someone either put a thinner headgasket or thinner headgasket. Same thing would apply if they milled the head.

The piston is still travelling the same amount, but there could be more or less area under the valves.

anyone know?

turbochic

when i figured my displacement out on my car with the 2mm head gasket it changed but only a tiny amt
example before: 1590.5858
example after gasket: 1590.6099

JimBlake

NO

Displacement is defined as the volume swept by the piston between TDC & BDC. It's not even corrected for the non-flatness of the piston or the head. It's just like this:

disp = pi/4 * bore^2 * stroke

Compression ratio is what changes with your headgasket.

Rob Dizzle

okay, so displacement is changed. at least in terms of how displacement is defined.

but, the volume in the cylinder changes.

would this effect power in any way?

MikeMAN

no.

the displacement is the minimum volume of the combustion chamber subtracted from the maximum volume of the combustion chamber. sure your max volume has gone up, but so has your minimum

very interesting to think about..i drew it out and it makes perfect sense

example:

<U>No Headgasket:</U>

Max Volume is 10
Minimum is 5
-------------------
Difference = 5

<U>1mm Headgasket *hypothetical:</U>

Max Volume has increased to 11
But minimum has ALSO increased to 6
-------------------------------------------
Difference = 5


hope that helps

mike

simple4012

bore and stroke are the only things that determine displacement

MikeMAN

thats what i was trying to explain in a round about way

that the area the piston is displacing is still the same...

i apologize if it was confusing! :D

hehe,
mike

WundedSaint

Your compression ratio can be changed with the headgasket though.