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This is the exact reason i have been trying , SO HARD, to find actual minimum squish #'s.
To increase my chanses of NOT having a knock.

I think i almost found out the HARD WAY.:woohoo:
when i took my 1327cc apart i remaeasured the squish. i had set it up at .047", but the gaskets sqeezed .011" more than i had antisipated. i ended up with .036" squish. Wow. that could have been costly.
is seems that the boring of the cases for the big sleeves leaves very little gasket at the base and less than normal at the head. so they squeezed more than usual.
a standard base gasket comes at .020" and will squeese to .018" but my 1327 base gasket ended up at .012". oop's.
Anyways. this was a great positive learning experiance.
I had LOw squish ,wich as u said = more compresion. but i had no ping. i do have 40* of overlap.

martijn, how much do u have? what cams?

mark1122 wrote:

This is the exact reason i have been trying , SO HARD, to find actual minimum squish #'s.
To increase my chanses of NOT having a knock.

I think i almost found out the HARD WAY.:woohoo:
when i took my 1327cc apart i remaeasured the squish. i had set it up at .047", but the gaskets sqeezed .011" more than i had antisipated. i ended up with .036" squish. Wow. that could have been costly.
is seems that the boring of the cases for the big sleeves leaves very little gasket at the base and less than normal at the head. so they squeezed more than usual.
a standard base gasket comes at .020" and will squeese to .018" but my 1327 base gasket ended up at .012". oop's.
Anyways. this was a great positive learning experiance.
I had LOw squish ,wich as u said = more compresion. but i had no ping. i do have 40* of overlap.

martijn, how much do u have? what cams?

I understand what you are saying. Good squish would set up a better burn pattern (better flame travel) We are just stuck with the gas we have (Thank You EPA) I think what saved you was the late opening point of your intake valve and the long duration of your cams. Your right, no knock but the power band just wasn't where you wanted it or needed it.

mark1122 wrote:

this is fun.
you are right, but you are also wrong.
why do we have squish?
To improve the flame travel and speed it up.
if u tighten the squish, u increase the presure. yes
but we will improve the flame and the pro's will over ride the cons.
This comes from Kevin Cameron.
U will get more detonation from a 9:1 with poor squish than a 10:1 with good squish clearance.

if u want to reduce the presure u are better served to change the cam timing. no cost involved . no risk.
the gasket just wont work.

Your first pictures that you posted showed what happens when you have the intake retarded. The motor will decide how it wants the intake timing. When I say change with the times, what about a 9:1 with good squish? That would give you performance and you could run on pump gas. There are so many guys that build motors that have never measured squish, a day in there lifes. Somehow they just seem to get by, without the engine knocking.

You double click on the photo to enlarge it.
I guess I blew it! I'll try again..........

double click.

Double click on photo.