is it possible to bump up your compressioon to,,,,285,285,285,285, just by doing head work?,,,,,one more thing what is the difference between compression reading,,,,,,285 and reading it like this 11/9 ?

 

"JUST" head work could mean lots of things. Shaving the head can raise it, but generally an agressive camshaft can lower it.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 7speed &raquo;</TD></TR><TR><TD CLASS="quote">... reading it like this 11/9 ?</TD></TR></TABLE>That sounds like you're talking about compression ratio. But it's expressed like 11.9:1 or 'eleven point nine to one'. That's only sorta related to compression pressure. Compression ratio is only related to the volumes of the cylinder and combustion chamber.

Say 2 engines with the same compression RATIO, but different camshafts. One camshaft has more overlap; that engine will probably have lower compression PRESSURE.

 

you are talking about 2 totally different things. compression readings you get from doing a compression test on each cylinder means absolutely nothing by themselves. it can be manipulated to read more or less depending on the tester used and the method used.

the compression ratio however can be bumped up with certain head work and other methods.