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I measured the two heads I have in use.
the 12:1 compression head measures 3.18" and the 11.5:1 head measures =
about 3.23. Both heads are installed so perfect measurements are tough =
to get. nonetheless, if your head was milled that much you would have =
numerous openings into the water passages.
Two solutions - find another head or two and test them before any work =
is done to see if you can find a better casting, or consider pop-up =
pistons.
I just checked piston to valve clearance on my new engine with modeling =
clay and there is certainly room to do this, though it may create other =
problems. I'm running a cam with 0.554" of valve lift and there was =
easily 0.080" of clearance at the closest condition based on the =
modeling clay.
On Apr 10, 2015, at 9:07 PM, damys--- via Fot wrote:
So we just got the head back from the sonic test, picture attached. Our =
numbers are quite a bit less than Chuck's. Do you guys think we will be =
OK at .065? Our compression, according to our calculations, is 9.76:1. =
This seems low to us. Our combustion chambers are 34.5 cc's. The =
total thickness of our head is 3.283, and we're bored .010 over.
Does the compression seem right for this thin of a head? Are we OK with =
only .065" of material to the water jacket?
Thanks,
Dave and Alex
<IMAG1545.jpg>_______________________________________________
fot@autox.team.net
http://www.fot-racing.com
Archive: http://www.team.net/archive
http://autox.team.net/mailman/options/fot/sjanzen@me.com
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<html><head></head><body style=3D"word-wrap: break-word; =
-webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">I =
measured the two heads I have in use.<div>the 12:1 compression head =
measures 3.18" and the 11.5:1 head measures about 3.23. Both heads =
are installed so perfect measurements are tough to get. =
nonetheless, if your head was milled that much you would have =
numerous openings into the water passages.</div><div>Two solutions - =
find another head or two and test them before any work is done to see if =
you can find a better casting, or consider pop-up pistons.</div><div>I =
just checked piston to valve clearance on my new engine with modeling =
clay and there is certainly room to do this, though it may create other =
problems. I'm running a cam with 0.554" of valve lift and there =
was easily 0.080" of clearance at the closest condition based on the =
modeling clay.</div><div><br></div><div><br></div><div><div><div>On Apr =
10, 2015, at 9:07 PM, damys--- via Fot wrote:</div><br =
class=3D"Apple-interchange-newline"><div align=3D"LEFT"><font =
face=3D"Verdana" size=3D"2" color=3D"#000000" letterspacing=3D"0" =
kerning=3D"0">So we just got the head back from the sonic test, picture =
attached. Our numbers are quite a bit less than Chuck's. Do =
you guys think we will be OK at .065? Our compression, =
according to our calculations, is 9.76:1. This seems low to =
us. Our combustion chambers are 34.5 cc's. The total =
thickness of our head is 3.283, and we're bored .010 =
over.</font></div><font face=3D"Verdana" size=3D"2" color=3D"#000000" =
letterspacing=3D"0" kerning=3D"0"><br></font><div align=3D"LEFT"><font =
face=3D"Verdana" size=3D"2" color=3D"#000000" letterspacing=3D"0" =
kerning=3D"0">Does the compression seem right for this thin of a =
head? Are we OK with only .065" of material to the water =
jacket?</font></div><font face=3D"Verdana" size=3D"2" color=3D"#000000" =
letterspacing=3D"0" kerning=3D"0"><br></font><div align=3D"LEFT"><font =
face=3D"Verdana" size=3D"2" color=3D"#000000" letterspacing=3D"0" =
kerning=3D"0">Thanks,</font></div><font face=3D"Verdana" size=3D"2" =
color=3D"#000000" letterspacing=3D"0" kerning=3D"0"><br></font><div =
align=3D"LEFT"><font face=3D"Verdana" size=3D"2" color=3D"#000000" =
letterspacing=3D"0" kerning=3D"0">Dave and =
Alex</font></div><span><IMAG1545.jpg></span>________________________=
_______________________<br><a =
href=3D"mailto:fot@autox.team.net";>fot@autox.team.net</a><br><br>http://ww=
w.fot-racing.com<br><br>Donate: =
http://www.team.net/forums<br>Unsubscribe/Manage: =
http://autox.team.net/mailman/options/fot/sjanzen@me.com<br><br><br></div>=
<br></div></body></html>=
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_______________________________________________
fot@autox.team.net
http://www.fot-racing.com
Archive: http://www.team.net/archive
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