> On Mon, 18 Jul 1994, Patrick Golder wrote:
> > Boring the cylinders will give you *lower* compression, because you've
> > increased the volume in the cylinders. Milling the head will decrease
> > the volume, and therefore increase the compression.
And Chip Old <feold@umd5.umd.edu> said:
> No, boring the cylinders raises the compression ratio. Compression ratio
> is the ratio between the swept volume of the cylinder and the volume of
> the combustion chamber. When you increase the swept volume (by boring)
> you end up with more air being squeezed into the original combustion
> space. When you decrease the chamber volume (by milling), you end up with
> the original volume of air being squeezed into a smaller combustion space.
> In both cases, the compression ratio is raised.
To which I reply, with a puzzled expression, "Gosh, guys! It seems like,
given that boring the cylinder only increases the area of the circular surface,
and has no effect on the ratio of stroke to overall cylinder length, it would
increase the displacement, but the compression ratio should stay the same."
It seems like milling the heads will change the the ratio of swept volume
(which stays the same) to overall volume (which decreases), which would raise
the compression ratio. Clearly, I'm missing something.
Fade to a high school math class, several years ago. #2 daughter asks algebra
teacher for help trying to figure out why her homework answers don't match
those of other students. She sez something like "My Dad helped me last night,
but the answers don't match the answers on the board."
Teacher, examining offered paper sez (in an amazed voice), "This is wonderful!
What an imagination! I've never seen anything like this before!" Switches to
stern voice. "Don't _EVER_ let this person help you again!"
Commute car - "7T6 MGB"
Disclaimer: Any opinions are my own and have |
nothing to do with the official policy or the | -bill
management of L.B.L, who probably couldn't | wlbrown@lbl.gov
care less about employees who play with trains. |
|