Squish range?

[BLEEDRED]

What is the best squish for me to run in my 440? I ended up with a warped jug and had to deck .010" off. Looking to get this thing set up soon. I don't run with a rev box and am only running about 10.9:1 CR. I was thinking the squish should be around .040" but it looks like I could be at .036"-.038. Thanks in advance.

[BLEEDRED]

I think most agree that .040" is about right. I might be close to .036-.038", think that's ok?

[2muchquad]

that sounds like your in the ball park:)

[BLEEDRED]

that sounds like your in the ball park

Wow, thanks.

So nobody's up on squish?

[insaneracin2003]

Originally posted by BLEEDRED
Wow, thanks.

So nobody's up on squish?
im not quite sure what squish means :confused: im not a motor person but i am willing to learn since im goimg to be building me a motor soon

[BLEEDRED]

The Squish Band or "Quench" is defined as that area between
the flat of the piston and the flat of the cylinder head at
top dead center (TDC). On the compression stroke, as the
piston approaches TDC, the compressed mixture of fuel and air
is "squished" to the remaining space of the combustion
chamber where the spark plug and valves reside.
The "squeezing" of the mixture creates turbulence and is
expected to promote a better and more complete combustion.

This also might help.

Deck Height: The distance between the flat "quench" surface
of the piston and the top of the bare cylinder (no head
gasket). Typically an engine is set to zero deck height with
the head gasket (compressed value) defining the "squish band"
value. If the value is negative this indicates the piston's "quench" surface extends above the top of the bare cylinder.

[insaneracin2003]

oh,makes sense now,i just never heard it pronounced that way.......sweet.thanks

[Cody_300ex]

I think when I rebuilt my 300ex it was in the mid .030's with a 11:1 weisco.

[BLEEDRED]

I think when I rebuilt my 300ex it was in the mid .030's with a 11:1 weisco.

Think is a key word. I assume you had no problems?

[wilkin250r]

There is no "perfect" number. If you can rebuild your engine to exact specs within a thousands of an inch, I applaud you. I can't get that percise.

0.035 to 0.045 is pretty good. Just as an added measure of safety, I would double-check the piston-valve clearance.

[dork]

i set up one motor with .028-.030" and it has been fine. it also had a tight rod with new piston and pin with good valve clearance. the reason there is a range of clearance is because of piston rock at tdc. it seems the best way to measure it is with solder on the piston and then measure with a micrometer. but .035-.040 will keep things safe.

[Cody_300ex]

Originally posted by BLEEDRED
Think is a key word. I assume you had no problems?

I'm giving 440ex's a run for there money so yea its holding up damn good.

[BLEEDRED]

Checked it out last night with a piece of solder. It's about .038". I'm fine with that.

[MIKE400EX]

Measure the squish on the left or right sides of the piston (above the pin ends) that way you'll eliminate rock due to piston/cyl. clearance.

[BLEEDRED]

Yup, I always measure it over the wrist pin on either side. Thanks.