CCing Cylinder for Compression Calculation

[Darren Blake]

Anyone here have any experience cc'ing the combustion chamber for compression calculation? I've done conventional cylinder heads, but never in a cylinder for obvious reasons. My pistons have no P/N's that I can identify for calculating compression ratio, so I have to figure it out myself.

 

[buildit]

You can use a deck bridge with dial indicator, and a degree wheel, to establish an exact TDC. Then fill the chamber with modeling clay and level the top of the clay even with the deck with a precision straight edge. (I do not force the clay between the piston/cylinder wall and top ring land. You can calculate this separately.) Then pull out the clay and put into a 250cc beaker and measure the amount of water needed to fill the beaker. This gives you your chamber volume. You get your cyl. head volume with a lexan plate and measuring burette in the standard way. For the gasket chamber volume, you have two half-circles with a small rectangle between them. With the compressed gasket thickness value, you calculate the gasket volume.

 

[Skip FIx]

I used the lexan /burrette and liquid on top of the cylinder/piston at TDC also.

 

[benchseat4speed]

Ditto^^

 

[MRHP]

I just guess!

 

[Darren Blake]

Ok so I'm not too crazy then! lol. I like the modeling clay idea also!

 

[Skip FIx]

My issue with modeling clay is the stuff sticks to the parts. You can spray WD 40 first but it can still stick. Like using it to check V-P when you cut it to check depth the always stretches as some part is stuck.

I do have here the numbers from my build block/piston and Edelbrock chamber in a post.

 

[Darren Blake]

Thank you Skip Flx. I have single valve relief Ross flat top pistons, however the only number on them is 437 which I assume is a forging number.

 

[Skip FIx]

On the bottom of the piston on the pin boss area Rosses generally have engraved a job # . they usually can look it up and give you specs.

 

[models916]

Play-doh instead of clay. No stick.

 

[Ishiftem]

And it tastes good.

 

[MRHP]

Which is better Dan, play-doh, crayons, or elmers glue?

 

[Ishiftem]

A slice of play doh + paste + 2 crackers = crazy delicious. Crayons? Only losers eat crayons.

 

[MRHP]

Good stuff right there Dan. I had to tell Mandy that one.

 

[303Radar]

And it tastes good.

Less filling!

 

[Ishiftem]

 

[MRHP]

Cant argue with that.

 

[Last 60]

When I was in grade school I always liked the taste of the white paste we used in Art class.

Lonnie

 

[scott hall]

Sorry fellers now you know the rest of the story. Makes me proud.

 

[63 dream'n]

Silly puddy.........